張媛媛, 陳靜雯, 盧 丹, 鮑宗必, 楊啟煒, 楊亦文, 張治國(guó)

硝基芳烴選擇性加氫催化劑的研究進(jìn)展

張媛媛1,2, 陳靜雯1,2, 盧 丹1,2, 鮑宗必1,2, 楊啟煒1,2, 楊亦文1,2, 張治國(guó)1,2

（1. 生物質(zhì)化工教育部重點(diǎn)實(shí)驗(yàn)室, 浙江大學(xué) 化學(xué)工程與生物工程學(xué)院, 浙江 杭州 310027;2. 浙江大學(xué)衢州研究院, 浙江 衢州 324000）

苯胺類衍生物是一類重要的精細(xì)化工中間體，工業(yè)上主要通過(guò)硝基芳烴的催化加氫反應(yīng)制備得到。然而，當(dāng)硝基芳烴底物分子中存在鹵素基團(tuán)或其他可還原性基團(tuán)時(shí)，極易發(fā)生過(guò)度加氫。針對(duì)此問(wèn)題，高效和高選擇性加氫催化劑的開(kāi)發(fā)已成為研究的焦點(diǎn)內(nèi)容。文章綜述了近年來(lái)硝基芳烴選擇性加氫催化劑的研究進(jìn)展，重點(diǎn)介紹了不同種類的非均相催化劑及其改性策略，主要包括貴金屬催化劑、非貴金屬催化劑和無(wú)金屬炭催化劑，同時(shí)總結(jié)了部分催化劑對(duì)不同類型硝基芳烴的選擇性加氫性能。最后對(duì)該領(lǐng)域的研究情況進(jìn)行了總結(jié)與展望。

硝基芳烴；苯胺類衍生物；選擇性催化加氫；氫氣

1 前言

苯胺類衍生物是一類重要的精細(xì)化工中間體，作為原料廣泛應(yīng)用于醫(yī)藥、農(nóng)藥、橡膠和染料等化學(xué)品的生產(chǎn)中[1-2]。工業(yè)上常通過(guò)硝基芳烴的還原制備苯胺類化合物，一般包括鐵粉還原法，硫化堿還原法，電化學(xué)還原法，轉(zhuǎn)移氫化法和催化加氫法等。其中，催化加氫法以氫氣為還原劑，具有優(yōu)異的經(jīng)濟(jì)性和綠色環(huán)保性，是工業(yè)上制備苯胺的常用手段。但是，當(dāng)?shù)孜锓肿又写嬖谄渌舾行曰鶊F(tuán)時(shí)，催化加氫過(guò)程中極易發(fā)生過(guò)度加氫生成副產(chǎn)物[3-4]，這不僅降低了反應(yīng)收率，而且增加了后續(xù)的分離純化難度。因此，如何實(shí)現(xiàn)硝基芳烴的高效選擇性催化加氫已經(jīng)成為研究的焦點(diǎn)。

根據(jù)底物分子上取代基類型的不同，硝基芳烴選擇性催化加氫反應(yīng)主要可分為2類：一是鹵代硝基芳烴的選擇性加氫；二是含有其他不飽和官能團(tuán)的硝基芳烴的選擇性加氫。對(duì)于前者而言，一方面硝基和鹵素原子會(huì)在加氫活性位點(diǎn)發(fā)生競(jìng)爭(zhēng)性吸附，另一方面還原產(chǎn)物中的氨基通過(guò)誘導(dǎo)電子轉(zhuǎn)移增強(qiáng)鹵素原子上的電子云密度，從而削弱碳-鹵鍵強(qiáng)度，使鹵素在反應(yīng)過(guò)程中極易脫落。一般來(lái)說(shuō)，隨著取代基F、Cl、Br、I的電負(fù)性依次減弱，碳-鹵鍵也越容易斷裂[5]。除鹵素外，當(dāng)?shù)孜镏泻刑?碳不飽和鍵(如─C═C、─C≡C)或碳-雜原子不飽和鍵(如─C≡N、─C═O)時(shí)，加氫極易發(fā)生在該類不飽和鍵上，其中含有─C═C和─C≡C的硝基芳烴是具有挑戰(zhàn)性的底物。一些復(fù)雜的底物分子同時(shí)含有多個(gè)敏感基團(tuán)，進(jìn)一步增大了選擇性還原硝基的難度。為解決該類底物低選擇性轉(zhuǎn)化的問(wèn)題，各類高效選擇性加氫催化劑被廣泛報(bào)道，本綜述較系統(tǒng)地介紹了近年來(lái)硝基芳烴選擇性加氫催化劑(非均相)的研究進(jìn)展。

2 貴金屬催化劑

鈀(Pb)、鉑(Pt)、釕(Ru)等貴金屬催化劑具有較高的加氫活性，已經(jīng)廣泛用于硝基芳烴催化加氫反應(yīng)中。然而，簡(jiǎn)單的負(fù)載型貴金屬催化體系普遍存在選擇性較低的問(wèn)題，限制了其在硝基芳烴還原中的進(jìn)一步應(yīng)用。針對(duì)貴金屬催化體系選擇性低的難題，近年來(lái)研究者們提出了多種調(diào)節(jié)及改性策略，主要包括調(diào)變載體種類及性質(zhì)、雙金屬協(xié)同催化、單原子催化、金屬界面效應(yīng)和空間限域效應(yīng)等等。

2.1 調(diào)變載體種類及性質(zhì)

對(duì)于負(fù)載型催化劑而言，載體的種類及性質(zhì)對(duì)催化活性與選擇性具有關(guān)鍵影響。金屬氧化物是最常用的載體，金屬/氧化物選擇性催化加氫體系已有大量報(bào)道，比如Pt/Fe2O3[6]、Au/SiO2[5]、Au/Fe2O3[7]、Pt/ZnO[8-9]，Pd/ZnO[10]、Au/Al2O3[11]、Ag/Al2O3[12]、Pd/CeO2[13]等等。其中，Boronat等[14]和Corma等[7,15-16]的研究表明，還原性載體TiO2可以通過(guò)金屬-載體的強(qiáng)相互作用(strong metal-support interaction，SMSI)及對(duì)硝基的優(yōu)先吸附，有效提升催化活性與選擇性。當(dāng)?shù)孜锷嫌幸蚁┗⑷┗?、氰基和碘等取代基時(shí)，Au/TiO2、Pt/TiO2、Ru/TiO2和Ni/TiO2在保持高轉(zhuǎn)化率的同時(shí)能夠?qū)崿F(xiàn)85%～100% 的選擇性(見(jiàn)圖1)。

基于Corma等的工作，一系列以TiO2為載體的貴金屬催化劑被開(kāi)發(fā)并應(yīng)用到了硝基芳烴選擇性加氫反應(yīng)中，如Au/TiO2[17]、Au/TiO2/UVM-7[18]、Au-MTA[19]、Pt/TiO2[20]、Pd/TiO2[10]、PtTW[21]等等。2019年，Macino等[22]指出Pt/TiO2界面處的外圍位點(diǎn)可能是硝基芳烴選擇性加氫的活性位點(diǎn)。在還原的條件下，Pt負(fù)載質(zhì)量分?jǐn)?shù)為0.2% 和0.5% 的催化劑會(huì)產(chǎn)生SMSI效應(yīng)，使得TiO覆蓋在活性Pt位點(diǎn)表面，從而降低了催化活性與選擇性，可以通過(guò)對(duì)催化劑的預(yù)煅燒防止這一現(xiàn)象發(fā)生。最近，Zhang等[23]進(jìn)一步研究了不同晶型TiO2對(duì)催化活性的影響，發(fā)現(xiàn)Ru/TiO2(金紅石)主要促進(jìn)偶聯(lián)過(guò)程，而Ru/TiO2(銳鈦礦)則可以高選擇性得到各類取代芳胺(轉(zhuǎn)化率和選擇性均大于99.9%)。

圖1 Au/TiO2催化硝基芳烴選擇性加氫反應(yīng)[15]

對(duì)氧化物進(jìn)行改性，可以進(jìn)一步提升其與金屬或底物的相互作用，已報(bào)道的體系如PtTW[21]、Fe3O4-NH2-Pd[24]、Fe3O4@PPy-Pt[25]等等。2017年，Tamura等[26]用金屬氧化物(MoO、WO和ReO)對(duì)Ru/SiO2進(jìn)行改性，發(fā)現(xiàn)Ru-MoO/SiO2(Mo、Ru物質(zhì)的量比為1:2)對(duì)各類還原性官能團(tuán)取代的芳硝基底物都具有高活性與選擇性(均大于90%)。研究表明，Ru與MoO的界面處會(huì)形成活性位點(diǎn)，在該位點(diǎn)上，MoO對(duì)底物有強(qiáng)吸附作用，而Ru上則形成了活性氫化物，從而顯著提升了活性和選擇性。2018年，Wang等[27]在TiO2載體上引入單位點(diǎn)的Sn，Sn─O─Ti鍵有利于TiO2上氧空位的形成，促進(jìn)硝基脫氧生成亞硝基，而貴金屬則為亞硝基加氫提供了活性位點(diǎn)。以Sn-TiO2為載體，Au、Pt、Ru、Ni對(duì)各類硝基底物的催化活性和選擇性均得到顯著提升。

除氧化物載體之外，一些表面含有雜原子摻雜的炭材料也可以充當(dāng)硝基的吸附位點(diǎn)，相應(yīng)的體系如Pd-Ph2S/C[28]、Au/C(En)[29]、Ru/CN[30]、Ir/MWCNTs[31]、Pt/N-CMK-3[32]、Ru/CNTs[33]、Pd-P-C[34]等等。2018年，Wu等[35]通過(guò)硝酸和磷摻雜對(duì)活性炭進(jìn)行了前處理，制備了一種可轉(zhuǎn)換產(chǎn)物選擇性的Pt/C催化劑。結(jié)果表明，經(jīng)過(guò)硝酸處理后，活性炭表面的酸性含氧官能團(tuán)數(shù)量顯著增加，而炭載體表面官能團(tuán)和雜原子磷對(duì)催化過(guò)程產(chǎn)生關(guān)鍵影響(見(jiàn)圖2)。在低溫還原的催化劑中，靠近Pt納米顆粒的酸性基團(tuán)通過(guò)氫鍵與底物的硝基相互作用，使乙烯基更靠近活性金屬中心，選擇性加氫生成1-乙基-3-硝基苯(轉(zhuǎn)化率95%，選擇性93%)；而在催化劑被高溫還原的過(guò)程中，P與Pt通過(guò)相互作用形成Pt-PO復(fù)合物，這種復(fù)合物更傾向于吸引極性硝基，從而選擇性生成對(duì)氨基苯乙烯(轉(zhuǎn)化率91%，選擇性96%)。

圖2 Pt/ACH-150和Pt/ACH-450催化劑上3-硝基苯乙烯選擇性加氫示意圖[35]

2.2 雙金屬協(xié)同催化

構(gòu)建雙金屬催化劑是調(diào)變活性與選擇性的有效策略。通常來(lái)說(shuō)，一種金屬組分(往往是貴金屬)具有較高的催化活性，另一種則主要起到調(diào)節(jié)結(jié)構(gòu)或電性的作用，二者協(xié)同提升活性與選擇性。近年來(lái)報(bào)道的雙金屬催化體系有PtSn/H-MoO[36]、Ru3Ni1[37]、Ni-Au/C[38]、NHC@AuPd/TiO2[39]、PdCo@SiO2[40]、RhIn/SiO2[41]、Cu/C-Pt[42]、Co/Pt/PAC[43]、Pt-Zn/SiO2[44]等等。2017年，Mao等[45]將一定量的Co原子摻入Ru中使其產(chǎn)生晶格應(yīng)變，并通過(guò)高分辨透射電鏡和X射線吸收精細(xì)結(jié)構(gòu)研究證實(shí)Ru晶格的壓縮現(xiàn)象，Ru─Ru鍵的收縮程度隨Co含量升高而增大。實(shí)驗(yàn)結(jié)果表明，當(dāng)Ru存在3% 的晶格應(yīng)變時(shí)，其對(duì)4-硝基苯乙烯的加氫選擇性從66% 提高到99%。密度泛函理論(density functional theory，DFT)結(jié)果表明，優(yōu)化的橫向壓縮應(yīng)變?cè)谧璧K乙烯基的氫化的同時(shí)促進(jìn)了硝基的氫化。

同年，Pei等[46]合成了一系列金屬間化合物PtM-和Pt3M-型催化劑(M = Sn, Pb, Zn)。相較于Pt和Pt3M-型，PtM-型金屬間化合物在3-硝基苯乙烯催化加氫中展現(xiàn)了優(yōu)異的選擇性(> 99%)，其中PtSn@mSiO2的轉(zhuǎn)化率為99%。研究表明，PtSn的表面結(jié)構(gòu)不僅改變了加氫途徑，而且促進(jìn)了硝基的優(yōu)先吸附。2019年，Han等[47]通過(guò)犧牲模板法在氮摻雜碳納米管上制備了一種PtZn金屬間化合物(見(jiàn)圖3)，在該催化劑中，Pt原子比Zn原子具有更高的電子密度，Zn原子促進(jìn)了硝基的吸附與氫原子的擴(kuò)散。該催化劑在對(duì)硝基苯乙炔選擇性加氫中的轉(zhuǎn)化率與選擇性均超過(guò)99%，優(yōu)于Pt單原子催化劑。

圖3 中空氮摻雜碳納米管負(fù)載PtZn金屬間化合物納米顆粒[47]

2.3 單原子催化劑

單原子催化劑(single atom catalyst，SAC)是Qiao等[48]于2011年提出的概念，他們利用FeO表面的缺陷錨定Pt原子，發(fā)現(xiàn)當(dāng)Pt負(fù)載質(zhì)量分?jǐn)?shù)為0.08%，且還原溫度為200 ℃時(shí)，Pt表現(xiàn)出類似孤立原子的結(jié)構(gòu)，通過(guò)同步輻射證明了質(zhì)量分?jǐn)?shù)為0.08% 的Pt/FeO中不存在強(qiáng)Pt─Pt金屬鍵。2014年，Wei等[3]將該類催化劑首次應(yīng)用到硝基芳烴的選擇性加氫反應(yīng)中，在40 ℃，0.3 MPa H2下對(duì)于各種官能化的底物都具有極高的活性(> 90%)和選擇性(> 98%)，轉(zhuǎn)換頻率(turnover frequency，TOF)高達(dá)1 500 h-1。作者將優(yōu)異的催化性能歸因于孤立的活性位點(diǎn)，SMSI效應(yīng)以及硝基的優(yōu)先吸附。2017年，Wei等[49]進(jìn)一步提高了Pt的負(fù)載量，并探討了堿金屬(Li+，Na+，K+等)對(duì)質(zhì)量分?jǐn)?shù)為2.16% 的Pt/FeO催化性能的影響。他們發(fā)現(xiàn)，一定量Na+的加入可以在保持3-硝基苯乙烯高轉(zhuǎn)化率的情況下，將選擇性從66.4% 提高到97.4%。研究表明，Na+與Pt/FeO催化劑通過(guò)相互作用形成了Pt-O-Na-O-Fe物種，這不僅防止了Pt原子的聚集，而且促進(jìn)了硝基基團(tuán)的優(yōu)先吸附。

基于Shi等[50]的開(kāi)創(chuàng)性工作，一系列單原子催化劑被開(kāi)發(fā)并應(yīng)用于硝基芳烴的選擇性催化加氫中。2018年，Peng等[51]在Ni納米晶體表面摻入Pt單原子，構(gòu)建了底物均勻吸附的催化劑構(gòu)型(見(jiàn)圖4)。在溫和條件下，該催化劑對(duì)硝基苯乙烯的TOF值可達(dá)1 800 h-1，選擇性大于99%，且對(duì)于各種官能團(tuán)取代的底物都表現(xiàn)出了適用性。研究表明，H2會(huì)在Pt和Ni原子上自發(fā)解離，生成的H原子在催化劑表面極易擴(kuò)散，為加氫過(guò)程提供了充足的氫。此外，Pt單原子和周圍的Ni原子協(xié)同誘導(dǎo)了3-硝基苯乙烯的吸附構(gòu)型，促進(jìn)了硝基的優(yōu)先活化。2019年，Lin等[52]制備了一種原子分散的Pt/α-MoC催化劑，該催化劑即使在5 000′10-6CO的存在下，也能實(shí)現(xiàn)對(duì)3-硝基苯乙烯催化加氫100% 的轉(zhuǎn)化率和99.9% 的選擇性。研究表明，Pt原子與α-MoC之間的相互作用削弱了CO在Pt上的吸附，獨(dú)特的界面結(jié)構(gòu)降低了硝基的加氫能壘。此外，水的加入不僅促進(jìn)了加氫過(guò)程，還增強(qiáng)了抗CO毒化性能。

圖4 Pt單原子摻雜的Ni納米晶體示意圖[51]

2.4 其他改性策略

除了上述策略，近年來(lái)也報(bào)道了一些新型的催化劑改性方法。比如，Chen等[53]提出可以通過(guò)界面效應(yīng)提高催化加氫選擇性。2020年[54]，他們發(fā)現(xiàn)在Pt納米粒子(nanoparticles，NPs)上沉積Fe(OH)可以有效促進(jìn)硝基的選擇性氫化，選擇性達(dá)到90% 以上。作者指出，選擇性的提高得益于Fe(III)-OH-Pt的界面，H2容易在暴露的Pt原子上分解為H原子，然后遷移到界面與OH反應(yīng)生成H2O和Fe2+，H2O的釋放導(dǎo)致Fe2+附近形成空位，F(xiàn)e2+的親氧性使其可以選擇性捕獲并還原硝基(見(jiàn)圖5)。此外，利用分子篩的空間限域效應(yīng)促進(jìn)硝基的選擇性吸附也是一種新策略[55-56]。如2017年，Zhang等[57]采用晶種定向合成方法將Pd NPs包封固定在Beta沸石中，得到的Pd@Beta催化劑對(duì)4-氯苯胺和4-氨基苯甲醛具有超過(guò)99% 的選擇性，而負(fù)載型催化劑(Pd/C，Pd/TiO2，Pd/Al2O3，Pd/SiO2)對(duì)4-氯苯胺的選擇性范圍僅為70.9%～89.6%。研究表明，沸石微孔改變了底物分子與Pd位點(diǎn)的吸附空間排列，使4-氯硝基苯通過(guò)硝基與Pd位點(diǎn)作用。利用該策略制備得到的Pd@MOR(MOR為絲光沸石)，Ru@Beta和Pt@Beta均展現(xiàn)了優(yōu)異的活性與選擇性。

圖5 硝基苯在Fe(OH)x/Pt表面催化脫氧機(jī)理[54]

3 非貴金屬催化劑

近年來(lái)，儲(chǔ)量豐富、價(jià)格低廉、環(huán)境友好的非貴金屬如Fe、Co、Ni、Cu作為硝基芳烴選擇性加氫催化劑也取得了一定進(jìn)展[58]。其中，Co基和Ni基催化劑得到了廣泛研究，F(xiàn)e基和Cu基催化劑也有少量報(bào)道。

3.1 鈷基催化劑

在非貴金屬選擇性加氫催化劑中，以鈷基催化劑的研究最為廣泛。2013年，Westerhaus等[59]報(bào)道了一種鈷-含氮配合物煅燒策略，研究發(fā)現(xiàn)，不同有機(jī)配體制備的催化劑在加氫活性上有顯著差異，其中由1,10-菲羅啉制備而成的Co-N-C復(fù)合催化劑具有最高的催化活性(見(jiàn)圖6)，對(duì)各類官能團(tuán)取代的硝基芳烴都表現(xiàn)出優(yōu)異的活性與選擇性，該策略也被用于制備鎳基[60]與鐵基催化劑[61]。2017年，F(xiàn)ormenti等[62]更換配體為α-二亞胺類分子，采用同樣的方法制備了新型Co催化劑，但催化活性相對(duì)1,10-菲羅啉并沒(méi)有明顯的提升，通過(guò)X射線光電子能譜(X-ray photoelectron spectroscopy，XPS)和動(dòng)力學(xué)實(shí)驗(yàn)推測(cè)未配位的吡啶二氮原子在催化活性中起著關(guān)鍵作用。同年，Sahoo等[63]又使用殼聚糖作為載體，利用殼聚糖上的氨基和羥基與鈷配位，制備了類似的材料，但催化能力較前2種催化劑反而有所下降。

圖6 Co-菲羅啉絡(luò)合物高溫?zé)峤庵苽銫o-N-C復(fù)合催化劑[59]

基于上述工作，大量Co/NC型催化材料被陸續(xù)報(bào)道[64-68]，其中金屬有機(jī)框架材料(metal organic frameworks，MOFs)因其高度有序的空間結(jié)構(gòu)和可調(diào)的配體，被認(rèn)為是理想的犧牲模板[69-73]。2020年，Wang等[74]以Zn/Co雙金屬ZIF骨架為前體，采用高溫?zé)峤庹舭l(fā)Zn原子的策略制備得到了負(fù)載在氮摻雜炭上的Co單原子催化劑(Co SAs/NC)。該催化劑中Co的質(zhì)量分?jǐn)?shù)為1.33%，且1個(gè)Co原子與4個(gè)氮原子配位，以單原子的形式存在。Co SACs/NC對(duì)各種取代的硝基底物都展現(xiàn)了優(yōu)異的活性與選擇性(均大于97%)。此外，作者對(duì)反應(yīng)的溶劑效應(yīng)進(jìn)行了研究，發(fā)現(xiàn)在溶劑乙醇中加入適量水有利于硝基苯的吸附和苯胺的解吸，從而提升反應(yīng)活性與選擇性。除了單一MOFs熱解外，還可以結(jié)合SiO2模板法進(jìn)一步調(diào)節(jié)催化劑結(jié)構(gòu)[75]。2018年，Sun等[76]通過(guò)將原硅酸四甲酯(TMOS)在Zn/Co雙金屬ZIF中水解，合成了具有介孔結(jié)構(gòu)和原子分散位點(diǎn)的Co@mesoNC催化劑(見(jiàn)圖7)。ZIF前體結(jié)構(gòu)中大量Zn和N的存在以及孔隙中SiO2可以有效阻止Co原子聚集。該催化劑在還原性官能團(tuán)取代的硝基底物催化加氫中展現(xiàn)出優(yōu)異的選擇性(> 93%)。

通常，熱解得到的Co/NC催化劑在組成上較為復(fù)雜，具有多種可能存在的加氫活性位點(diǎn)，比如金屬/氧化物納米顆粒、Co-N物種或載體表面摻雜的氮氧基團(tuán)，而活性物種的歸屬問(wèn)題長(zhǎng)期也存在爭(zhēng)議。2021年，Li等[77]系統(tǒng)考察4種文獻(xiàn)報(bào)道的Co/NC催化劑(見(jiàn)圖8)，其在3-硝基苯乙烯選擇性加氫反應(yīng)中均表現(xiàn)出優(yōu)異的活性與選擇性。溶劑效應(yīng)表明，4種催化劑均在質(zhì)子型溶劑中具有較高的活性，說(shuō)明活性中心與質(zhì)子型溶劑間可能存在由單原子Co-N結(jié)構(gòu)(類似于均相催化劑)所介導(dǎo)的質(zhì)子穿梭效應(yīng)。此外，研究者還通過(guò)毒化實(shí)驗(yàn)、酸洗實(shí)驗(yàn)和催化劑再生實(shí)驗(yàn)揭示了單原子物種Co-N物種是反應(yīng)的活性位點(diǎn)。

圖7 Co@mesoNC催化劑制備方法[76]

除了氮摻雜之外，其他雜原子摻雜的Co基催化劑也有報(bào)道[70-71,78]。2020年，Zhang等[79]利用牛血清白蛋白上的S原子固定Zn2+和Co2+，形成了蛋白質(zhì)-金屬離子網(wǎng)絡(luò)，熱解過(guò)程中金屬離子被還原，通過(guò)進(jìn)一步的酸處理形成了Co、N摻雜的多孔炭結(jié)構(gòu)。表征結(jié)果表明，Zn2+的引入有利于Co分散和多孔結(jié)構(gòu)的形成，酸處理可以去除大的Co納米顆粒，從而促進(jìn)活性位點(diǎn)的暴露。此外，催化劑中部分Co以CoZnS的形式存在，另一部分則形成了Co-N。該催化劑不僅對(duì)于各類硝基芳烴底物有著優(yōu)異的催化活性(轉(zhuǎn)化率100%，選擇性均大于98%)，還可以抵抗CO或H2S的毒化。

圖8 4種典型Co-N-C催化劑的合成方法[69]

3.2 鎳基催化劑

雷尼鎳是常見(jiàn)的工業(yè)鎳基催化劑，常用于有機(jī)化合物的加氫還原，但是與貴金屬一樣，它也具有較低的催化加氫選擇性。通過(guò)對(duì)雷尼鎳的改性可以有效提高其選擇性，如2012年，Lu等[80]發(fā)現(xiàn)雙氰胺改性過(guò)的雷尼鎳能將鄰氯硝基苯的反應(yīng)時(shí)間縮短3/4以上，選擇性接近100%。作者通過(guò)實(shí)驗(yàn)指出，雷尼鎳與雙氰胺分子中的氮原子之間存在很強(qiáng)的相互作用，可以覆蓋電子缺陷的Lewis酸位點(diǎn)Ni-H，從而切斷Cl…H-Ni中間態(tài)的形成，使脫氯受到抑制。2015年，Liu等[81]研究了金屬氟化物對(duì)雷尼鎳的影響，發(fā)現(xiàn)不同的金屬氟化物都能提升反應(yīng)活性與選擇性，其中CaF2> NaF ≈ KF > MgF2> 無(wú)氟化物。作者推測(cè)，添加的氟化物會(huì)沉積在催化劑表面，從而改變了雷尼鎳的電子性質(zhì)，但文中并沒(méi)有給出相應(yīng)的證明。

開(kāi)發(fā)新型鎳基催化劑是另一種可行的思路[82-85]，比如通過(guò)對(duì)載體的改性提升催化活性與選擇性[86]。2016年，Li等[87]制備出具有豐富表面缺陷的鎳納米催化劑層狀雙金屬氫氧化物NiTi-LDH(見(jiàn)圖9)。研究表明，金屬與載體之間具有強(qiáng)相互作用，且載體上形成了大量的氧空位和Ti3+物種。作者推測(cè)，表面氧空位會(huì)作為電子給體吸引氮原子，引發(fā)N─O鍵的活化，而Ti3+陽(yáng)離子可能會(huì)與硝基中帶負(fù)電的氧原子結(jié)合，從而定向誘導(dǎo)硝基的吸附。反應(yīng)動(dòng)力學(xué)也證實(shí)表面缺陷對(duì)鄰氯硝基苯的氫化起到促進(jìn)作用。2017年，Ren等[88]先用硝酸處理活性炭，再通過(guò)負(fù)載質(zhì)量分?jǐn)?shù)為5% 鎳還原得到一種改性催化劑Ni/ACox。載體表面生成的氧基團(tuán)有助于穩(wěn)定Ni NPs，使之具有更均勻的分布和更小的尺寸((5.5±0.8) nm和(8.3±2.3) nm)。研究表明，Ni/ACox能在非常溫和的條件下(40 ℃，0.3 MPa H2)，對(duì)3-硝基苯乙烯的氫化反應(yīng)實(shí)現(xiàn)98% 的轉(zhuǎn)化率和97% 的選擇性，此外，該催化劑對(duì)其他還原性基團(tuán)也有很好的耐受性。最近，Huang等[89]制備的TiO2@OAC載體結(jié)合了NiTi-LDH和ACox2種載體的優(yōu)勢(shì)，在負(fù)載金屬鎳后，對(duì)氯代硝基苯氫化具有優(yōu)異的催化性能。

圖9 NiTi-x可能的加氫機(jī)理示意圖[87]

與Co/NC結(jié)構(gòu)相似，以氮摻雜炭為載體的鎳催化劑也展現(xiàn)了出色的催化性能[90-92]。2016年，Hahn等[84]報(bào)道了一種復(fù)合材料Ni@SiCN，以聚苯乙烯作為軟模板，引進(jìn)氮配位的鎳絡(luò)合物和聚硅氮烷，再通過(guò)交聯(lián)、熱解、模板脫除和還原的步驟獲得介孔結(jié)構(gòu)的催化劑。研究表明，Ni NPs分布均勻，平均粒徑為5.5 nm。該催化劑對(duì)各種取代基都具有優(yōu)異的耐受性。2020年，Advani等[93]以生物質(zhì)殼聚糖為前體，通過(guò)浸漬-炭化法合成了一種Ni NPs負(fù)載的氮摻雜炭納米管Ni@NCNT，Ni NPs均勻分布，尺寸在10～15 nm。該催化劑在0.5 MPa H2和50 ℃下成功實(shí)現(xiàn)各類硝基芳烴的高效選擇性加氫。作者將催化劑的高活性和穩(wěn)定性歸因于鎳和氮摻雜炭之間形成的異質(zhì)結(jié)，具有較高費(fèi)米能級(jí)的鎳能自發(fā)地將電子提供給載體，從而在金屬和載體的界面上建立一個(gè)負(fù)責(zé)選擇性氫化的電荷區(qū)，促進(jìn)了加氫的進(jìn)行。

2018年，Ryabchuk等[94]以1,10-菲羅啉為配體制備一系列負(fù)載于無(wú)機(jī)載體上的氮摻雜鎳基納米催化劑，有趣的是，當(dāng)以SiO2為載體時(shí)，在1 000 ℃下熱解后會(huì)形成金屬間硅化鎳材料(見(jiàn)圖10)。實(shí)驗(yàn)結(jié)果表明，熱解溫度對(duì)于硅化鎳的形成至關(guān)重要，在800 ℃下，SiO2會(huì)發(fā)生還原，形成含量較低的Ni17Si3相；當(dāng)溫度升至1 000 ℃時(shí)，表面的硅原子進(jìn)一步分布到鎳晶格中，得到Ni31Si12/Ni2Si的混合物。將材料暴露于空氣后，Ni-Si納米顆粒的表面被氧化，形成NiO/SiO2殼。該催化劑具有很高的活性和選擇性，能在溫和條件下(60 ℃，1 MPa H2)實(shí)現(xiàn)各類硝基芳烴的高效選擇性轉(zhuǎn)化。

圖10 硅化鎳納米粒子的形成示意圖[94]

3.3 其他非貴金屬催化劑

除Co、Ni之外，鐵基[95-98]、銅基及雙金屬?gòu)?fù)合催化劑也有報(bào)道。Jagadeesh等[61,99]報(bào)道了以H2為還原劑的鐵基非均相催化體系，他們通過(guò)熱解鐵/菲羅啉配合物得到了一種具有氮摻雜石墨烯層包覆的活性Fe2O3NPs。對(duì)于還原性官能團(tuán)取代的硝基芳烴，該催化劑能以大于88% 的收率獲得相應(yīng)產(chǎn)物。2016年，Shi等[100]通過(guò)可再生生物質(zhì)(葡萄糖、木糖醇和蔗糖)與三聚氰胺的直接熱解，合成了嵌在碳納米管中的Fe3C，且納米顆粒被氮摻雜石墨烯層包裹。該催化劑在40 ℃下能實(shí)現(xiàn)各類鹵素取代的硝基芳烴的高效選擇性加氫。

Fe2P和FeS2[101-102]也被證明是有效的加氫活性位點(diǎn)。2018年，Zhu等[103]以Fe-MIL-88B-NH2為前體，進(jìn)一步反應(yīng)形成含P、S、N元素的聚合物外殼，最后一同熱解制備了摻雜在碳基體中的磷化鐵納米材料。該Fe2P@C催化劑能高選擇性地催化還原各種官能團(tuán)取代的硝基芳烴，其活性是商用Fe2P粉末的5倍。2019年，Duan等[104]在N、S摻雜的多孔炭上負(fù)載FeS2納米顆粒，得到一種具有高比表面積，高孔隙體積和分級(jí)孔道的新型催化劑FeS2/NSC。該催化劑能實(shí)現(xiàn)各種取代的芳硝基底物選擇性加氫，催化性能優(yōu)于其他文獻(xiàn)報(bào)道的FeS2和FeO類催化劑。實(shí)驗(yàn)和DFT計(jì)算表明，F(xiàn)eS2NPs與氮和硫摻雜的載體具有較強(qiáng)的相互作用，電負(fù)性較強(qiáng)的N原子和S原子使FeS2NPs帶有正電，有利于對(duì)硝基的優(yōu)先吸附。

有關(guān)銅基催化劑在H2氣氛下還原硝基芳烴的報(bào)道相對(duì)較少[105]，2016年，Kour等[106]報(bào)道了一種銅納米顆粒修飾的氮摻雜炭納米管。與前文的一些工作相似，作者用硫酸改性炭納米管，使之表面產(chǎn)生含氧官能團(tuán)，以碳酸胍作為摻雜用的氮源。在進(jìn)行硝基芳烴的還原實(shí)驗(yàn)時(shí)，發(fā)現(xiàn)當(dāng)在溶劑中加入乙酸，可以有效提高轉(zhuǎn)化率(95%)，且對(duì)于還原性基團(tuán)取代的底物具有高度選擇性。

此外，多種非貴金屬?gòu)?fù)合形成的催化劑有時(shí)具有協(xié)同效應(yīng)，展現(xiàn)優(yōu)于單一金屬的催化活性[107-108]。如2017年，Liu等[109]制備了具有薄碳涂層保護(hù)的Co@C、Ni@C、CoNi@C 3種催化劑。通過(guò)XPS等表征發(fā)現(xiàn)，Co@C表面由于空氣的氧化作用覆蓋著CoO物種，而Ni的引入可以對(duì)金屬Co起到穩(wěn)定作用，同時(shí)增強(qiáng)了H2的解離作用。在對(duì)3-硝基苯乙烯的還原實(shí)驗(yàn)中，就催化活性而言，Ni@C > Co-Ni@C > Co@C，但是Ni@C催化劑的選擇性僅為80%。相比之下，Co-Ni@C在保持一定的加氫活性的同時(shí)也顯示了高選擇性(> 97%)。

4 無(wú)金屬炭催化劑

相較于金屬催化劑，無(wú)金屬炭材料性質(zhì)穩(wěn)定、價(jià)格低廉和綠色環(huán)保，具有不可比擬的優(yōu)勢(shì)。早在1985年，Han等[110]以石墨烯為催化劑，水合肼為還原劑，實(shí)現(xiàn)了硝基芳烴的還原。但受限于炭材料自身的催化活性較低，對(duì)H2和硝基的吸附較弱，且H2在其表面無(wú)法解離，一直以來(lái)，使用該類材料促進(jìn)催化加氫過(guò)程的作用非常有限[111-112]。

圖11 無(wú)金屬雜原子改性的炭基材料[113]

為了提升炭材料的氫化活性，在碳基質(zhì)中摻雜無(wú)金屬雜原子(如N、P、S、B等)是一種常見(jiàn)的改性手段(見(jiàn)圖11)。摻雜的雜原子既可能充當(dāng)路易斯酸或堿中心，又會(huì)改變炭材料的物理化學(xué)性質(zhì)和氧化還原特性，比如引起電荷離域現(xiàn)象，使得炭材料呈現(xiàn)出類金屬結(jié)構(gòu)，有助于提升對(duì)H2的活化能力。此外，由于摻雜物和碳原子之間的配位鍵長(zhǎng)和原子大小均不相同，雜原子周圍通常會(huì)產(chǎn)生新的缺陷，缺陷位置的局部電荷富集，可以將更多的載流子轉(zhuǎn)移到吸附的H2和硝基上，從而促進(jìn)加氫過(guò)程的發(fā)生[113]。在已報(bào)道的材料中，石墨烯、富勒烯、Lewis酸-堿對(duì)固定炭材料、晶格缺陷碳和改性碳納米管等材料都被嘗試用于H2活化，與之相關(guān)的催化機(jī)理也紛紛被提出[114-115]。

2017年，Gao等[116]利用理論計(jì)算建立了4種模型，用于評(píng)估了磷摻雜和晶格缺陷對(duì)碳電子結(jié)構(gòu)的影響。計(jì)算結(jié)果表明，電子會(huì)傾向于聚集在磷摻雜物和缺陷附近的碳原子上，電子離域使能帶結(jié)構(gòu)呈現(xiàn)類金屬狀態(tài)，其中，PV-C的費(fèi)米能級(jí)像金屬一樣完全位于導(dǎo)帶內(nèi)。同時(shí)，也通過(guò)計(jì)算證實(shí)了磷摻雜及其引起的缺陷能有效激活H2分子和硝基。研究者基于計(jì)算結(jié)果合成了PV-C，發(fā)現(xiàn)其晶格缺陷濃度(DG)與P摻雜濃度呈線性關(guān)系。在硝基芳烴的選擇性加氫實(shí)驗(yàn)中，PV-C在2 MPa H2，120 ℃下，能夠以優(yōu)異的收率和選擇性(> 90%)還原多種芳硝基底物(包含不飽和官能團(tuán)取代的底物)。值得注意的是，反應(yīng)的TOF值也線性依賴于磷摻雜濃度和DG。

研究表明，對(duì)碳納米管進(jìn)行雜原子摻雜可以提升其氫化能力。如2020年，Chen等[112]對(duì)碳納米管分別進(jìn)行磷元素和氮元素?fù)诫s，制備得到了P-CNT和N-CNT。與原始CNT相比，P-CNT和N-CNT都具有更大的比表面積和更多的晶格缺陷，且通過(guò)加入K2CO3添加劑可以進(jìn)一步增加其表面缺陷程度。結(jié)果顯示，P-CNT900具有最優(yōu)異的催化性能，不僅能夠?qū)崿F(xiàn)相對(duì)溫和條件下硝基苯的高效還原，而且對(duì)于含有敏感基團(tuán)的硝基底物，也顯示出優(yōu)異的轉(zhuǎn)化率與選擇性。此外，該催化劑在循環(huán)8次后也沒(méi)有明顯的活性和選擇性損失。文章指出摻雜到CNT基體中的磷原子可能會(huì)誘導(dǎo)表面電荷定位，促進(jìn)CNT表面獨(dú)立的受阻路易斯酸-堿對(duì)(frustrated Lewis pairs，F(xiàn)LP)的生成。這些FLP在反應(yīng)過(guò)程中充當(dāng)活性位點(diǎn)，通過(guò)H2極化和分裂，同時(shí)形成H-型和H+型位點(diǎn)來(lái)促進(jìn)H2活化(見(jiàn)圖12)。

在無(wú)金屬炭催化劑的研究中，也有學(xué)者提出了質(zhì)疑：在炭材料的合成過(guò)程中，盡管進(jìn)行了酸或堿的處理，但是仍然不可避免地會(huì)有痕量金屬殘留，一些研究工作忽略了殘留金屬的影響，對(duì)催化中心的判斷起到了誤導(dǎo)作用[117-118]。典型的例子是，2009年，Li等[119]報(bào)道稱利用富勒烯成功活化了分子氫。在紫外光輻射下(300 W高壓Hg燈或350 W Xe燈)，C60或C70的混合催化劑在室溫和常壓H2下就能實(shí)現(xiàn)硝基芳烴的高效催化加氫。在黑暗條件下，加氫過(guò)程在5 MPa H2，160 ℃的條件下也能順利進(jìn)行。但是次年，Pacosova等[120]就駁斥了這一發(fā)現(xiàn)，他們指出，在C60的合成過(guò)程中會(huì)使用鎳，可能是殘留的鎳發(fā)揮了催化作用。對(duì)照實(shí)驗(yàn)表明，用鎳還原法制備得到的C60會(huì)吸附溶液中的鎳，而當(dāng)用鈉代替鎳合成的C60是沒(méi)有催化活性的。

總體來(lái)說(shuō)，目前報(bào)道的無(wú)金屬炭材料催化加氫體系普遍存在催化劑用量高、反應(yīng)選擇性低、反應(yīng)條件苛刻、反應(yīng)時(shí)間長(zhǎng)等問(wèn)題，且催化機(jī)理并不明晰。雖然無(wú)金屬炭材料仍存在許多需要解決的問(wèn)題，距離工業(yè)化尚遠(yuǎn)，但不可否認(rèn)的是，它仍然是新型加氫催化劑研發(fā)的潛在方向。

5 催化劑的底物適用類型

硝基芳烴分子中取代基的類型決定了其選擇性加氫的難易程度，不同種類加氫催化劑往往具有不同的底物適用性。將前文重點(diǎn)介紹的各類代表性催化劑的底物適用類型統(tǒng)計(jì)于表1中，結(jié)果表明，經(jīng)過(guò)催化劑的設(shè)計(jì)與改性，無(wú)論是貴金屬催化劑、非貴金屬催化劑還是無(wú)金屬炭催化劑，都可能在優(yōu)化條件下實(shí)現(xiàn)各類硝基芳烴的高效選擇性加氫。

表1 部分催化劑對(duì)不同類型硝基芳烴的選擇性加氫性能

Note:= conversion,= selectivity,= yield

6 結(jié)論

綜上所述，針對(duì)硝基芳烴選擇性催化加氫反應(yīng)已經(jīng)開(kāi)發(fā)了多種貴金屬、非貴金屬、無(wú)金屬催化劑類型，且具有廣泛的底物適用性。貴金屬催化劑設(shè)計(jì)的難點(diǎn)在于控制選擇性，可以通過(guò)調(diào)節(jié)金屬相的組成和分散度、載體的表面性質(zhì)與空間結(jié)構(gòu)等手段改變催化劑與氫氣或底物的作用方式，從而實(shí)現(xiàn)對(duì)硝基的優(yōu)先活化。非貴金屬催化劑的設(shè)計(jì)重點(diǎn)在于提高加氫活性，利用雜原子(N、S、P等)摻雜調(diào)變金屬的電子性質(zhì)與穩(wěn)定性是目前最廣泛使用的策略，但是大多數(shù)非貴金屬催化劑仍存在反應(yīng)條件較為苛刻的問(wèn)題，如何實(shí)現(xiàn)溫和條件下的高效加氫仍是目前的一大挑戰(zhàn)。無(wú)金屬炭催化劑廉價(jià)綠色，但其發(fā)展仍處于初步階段，無(wú)論是反應(yīng)活性還是催化機(jī)理均有較大的探索空間。總體來(lái)說(shuō)，目前所報(bào)道的大多數(shù)催化劑雖然已經(jīng)實(shí)現(xiàn)了較高的選擇性催化加氫活性，但是其合成及應(yīng)用大多停留在實(shí)驗(yàn)室階段，且有的催化劑使用的前體昂貴，制備方法繁瑣，穩(wěn)定性較差，不適于進(jìn)一步的工業(yè)應(yīng)用，如何制備一種適用于工業(yè)生產(chǎn)的高效、高選擇性、綠色、經(jīng)濟(jì)的催化劑仍是未來(lái)的研究方向。

[1] DOWNING R S, KUNKELER P J, VANBEKKUM H. Catalytic syntheses of aromatic amines [J]. Catalysis Today, 1997, 37(2): 121-136.

[2] BLASER H U, MALAN C, PUGIN B,. Selective hydrogenation for fine chemicals: Recent trends and new developments [J]. Advanced Synthesis & Catalysis, 2003, 345(1/2): 103-151.

[3] WEI H, LIU X, WANG A,. FeO-supported platinum single-atom and pseudo-single-atom catalysts for chemoselective hydrogenation of functionalized nitroarenes [J]. Nature Communications, 2014, 5: 5634.

[4] SONG J, HUANG Z F, PAN L,. Review on selective hydrogenation of nitroarene by catalytic, photocatalytic and electrocatalytic reactions [J]. Applied Catalysis B-Environmental, 2018, 227: 386-408.

[5] FORMENTI D, FERRETTI F, SCHARNAGL F K,. Reduction of nitro compounds using 3d-non-noble metal catalysts [J]. Chemical Reviews, 2019, 119(4): 2611-2680.

[6] EVANGELISTI C, ARONICA L A, BOTAVINA M,. Chemoselective hydrogenation of halonitroaromatics over gamma-Fe2O3-supported platinum nanoparticles: The role of the support on their catalytic activity and selectivity [J]. Journal of Molecular Catalysis A-Chemical, 2013, 366: 288-293.

[7] CORMA A, SERNA P. Chemoselective hydrogenation of nitro compounds with supported gold catalysts [J]. Science, 2006, 313(5785): 332-334.

[8] BERGUERAND C, YARULIN A, CARDENAS-LIZANA F,. Chemoselective liquid phase hydrogenation of 3-nitrostyrene over Pt nanoparticles: Synergy with ZnO support [J]. Industrial & Engineering Chemistry Research, 2015, 54(35): 8659-8669.

[9] GAO T T, SHI W, ZHANG Y,. Finely controlled platinum nanoparticles over ZnO nanorods for selective hydrogenation of 3-nitrostyrene to 3-vinylaniline [J]. Chemistry-A European Journal, 2020, 26(41): 8990-8996.

[10] SUPRIYA P, SRINIVAS B T V, CHOWDESWARI K,. Biomimetic synthesis of gum acacia mediated Pd-ZnO and Pd-TiO2-promising nanocatalysts for selective hydrogenation of nitroarenes [J]. Materials Chemistry and Physics, 2018, 204: 27-36.

[11] SHIMIZU K I, MIYAMOTO Y, KAWASAKI T,. Chemoselective hydrogenation of nitroaromatics by supported gold catalysts: Mechanistic reasons of size- and support-dependent activity and selectivity [J]. Journal of Physical Chemistry C, 2009, 113(41): 17803-17810.

[12] SHIMIZU K I, MIYAMOTO Y, SATSUMA A. Size- and support-dependent silver cluster catalysis for chemoselective hydrogenation of nitroaromatics [J]. Journal of Catalysis, 2010, 270(1): 86-94.

[13] ZHANG S, CHANG C R, HUANG Z Q,. High catalytic activity and chemoselectivity of sub-nanometric Pd clusters on porous nanorods of CeO2for hydrogenation of nitroarenes [J]. Journal of the American Chemical Society, 2016, 138(8): 2629-2637.

[14] BORONAT M, CONCEPCION P, CORMA A,. A molecular mechanism for the chemoselective hydrogenation of substituted nitroaromatics with nanoparticles of gold on TiO2catalysts: A cooperative effect between gold and the support [J]. Journal of the American Chemical Society, 2007, 129(51): 16230-16237.

[15] CORMA A, CONCEPCION P, SERNA P. A different reaction pathway for the reduction of aromatic nitro compounds on gold catalysts [J]. Angewandte Chemie-International Edition, 2007, 46(38): 7266-7269.

[16] CORMA A, SERNA P, CONCEPCION P,. Transforming nonselective into chemoselective metal catalysts for the hydrogenation of substituted nitroaromatics [J]. Journal of the American Chemical Society, 2008, 130(27): 8748-8753.

[17] TORRES C, CAMPOS C, FIERRO J L G,. Nitrobenzene hydrogenation on Au/TiO2and Au/SiO2catalyst: Synthesis, characterization and catalytic activity [J]. Catalysis Letters, 2013, 143(8): 763-771.

[18] TRANDAFIR M M, MORAGUES A, AMOROS P,. Selective hydrogenation of nitroderivatives over Au/TiO2/UVM-7 composite catalyst [J]. Catalysis Today, 2020, 355: 893-902.

[19] TAMIOLAKIS I, FOUNTOULAKI S, VORDOS N,. Mesoporous Au-TiO2nanoparticle assemblies as efficient catalysts for the chemoselective reduction of nitro compounds [J]. Journal of Materials Chemistry A, 2013, 1(45): 14311-14319.

[20] YOSHIDA H, IGARASHI N, FUJITA S I,. Influence of crystallite size of TiO2supports on the activity of dispersed Pt catalysts in liquid-phase selective hydrogenation of 3-nitrostyrene, nitrobenzene, and styrene [J]. Catalysis Letters, 2015, 145(2): 606-611.

[21] CARRUS M, FANTAUZZI M, RIBONI F,. Increased conversion and selectivity of 4-nitrostyrene hydrogenation to 4-aminostyrene on Pt nanoparticles supported on titanium-tungsten mixed oxides [J]. Applied Catalysis A-General, 2016, 519: 130-138.

[22] MACINO M, BARNES A J, QU R Y,. Tuning of catalytic sites in Pt/TiO2catalysts for the chemoselective hydrogenation of 3-nitrostyrene [J]. Nature Catalysis, 2019, 2(10): 873-881.

[23] ZHANG J, PEI L J, WANG J,. Differences in the selective reduction mechanism of 4-nitroacetophenone catalysed by rutile- and anatase-supported ruthenium catalysts [J]. Catalysis Science & Technology, 2020, 10(5): 1518-1528.

[24] ZHANG F W, JIN J, ZHONG X,. Pd immobilized on amine-functionalized magnetite nanoparticles: A novel and highly active catalyst for hydrogenation and heck reactions [J]. Green Chemistry, 2011, 13(5): 1238-1243.

[25] LONG Y, YUAN B, NIU J R,. Distinctive size effects of Pt nanoparticles immobilized on Fe3O4@ppy used as an efficient recyclable catalyst for benzylic alcohol aerobic oxidation and hydrogenation reduction of nitroaromatics [J]. New Journal of Chemistry, 2015, 39(2): 1179-1185.

[26] TAMURA M, YUASA N, NAKAGAWA Y,. Selective hydrogenation of nitroarenes to aminoarenes using a MoO-modified Ru/SiO2catalyst under mild conditions [J]. Chemical Communications, 2017, 53(23): 3377-3380.

[27] WANG L, GUAN E J, ZHANG J,. Single-site catalyst promoters accelerate metal-catalyzed nitroarene hydrogenation [J]. Nature Communications, 2018, 9: 1362.

[28] ZHANG Q F, SU C, CEN J,. The modification of diphenyl sulfide to Pd/C catalyst and its application in selective hydrogenation of-chloronitrobenzene [J]. Chinese Journal of Chemical Engineering, 2014, 22(10): 1111-1116.

[29] BONDARENKO G N, BELETSKAYA I P. Activated carbon as an efficient support for gold nanoparticles that catalyze the hydrogenation of nitro compounds with molecular hydrogen [J]. Mendeleev Communications, 2015, 25(6): 443-445.

[30] YUE S N, WANG X G, LI S T,. Highly selective hydrogenation of halogenated nitroarenes over Ru/CN nanocomposites by in situ pyrolysis [J]. New Journal of Chemistry, 2020, 44(27): 11861-11869.

[31] LI H B, LIU L, MA X Y. Effective hydrogenation of haloaromatic nitro compounds catalysed by iridium nanoparticles deposited on multiwall carbon nanotubes [J]. Synthesis and Reactivity in Inorganic Metal-Organic and Nano-Metal Chemistry, 2016, 46(10): 1499-1505.

[32] SHENG Y, LIN X R, WANG X G,. Highly dispersed Pt nanoparticles on N-doped ordered mesoporous carbon as effective catalysts for selective hydrogenation of nitroarenes [J]. Catalysts, 2020, 10(4): 374.

[33] ANTONETTI C, OUBENALI M, GALLETTI A M R,. Novel microwave synthesis of ruthenium nanoparticles supported on carbon nanotubes active in the selective hydrogenation of-chloronitrobenzene to-chloroaniline [J]. Applied Catalysis A-General, 2012, 421: 99-107.

[34] LU C S, WANG M J, FENG Z L,. A phosphorus-carbon framework over activated carbon supported palladium nanoparticles for the chemoselective hydrogenation of-hloronitrobenzene [J]. Catalysis Science & Technology, 2017, 7(7): 1581-1589.

[35] WU Q F, ZHANG B, ZHANG C,. Significance of surface oxygen-containing groups and heteroatom P species in switching the selectivity of Pt/C catalyst in hydrogenation of 3-nitrostyrene [J]. Journal of Catalysis, 2018, 364: 297-307.

[36] SHU Y J, CHAN H C, XIE L F,. Bimetallic platinum-tin nanoparticles on hydrogenated molybdenum oxide for the selective hydrogenation of functionalized nitroarenes [J]. ChemCatChem, 2017, 9(22): 4199-4205.

[37] CAI S F, DUAN H H, RONG H P,. Highly active and selective catalysis of bimetallic Rh3Ni1nanoparticles in the hydrogenation of nitroarenes [J]. ACS Catalysis, 2013, 3(4): 608-612.

[38] LANG L M, PAN Z R, YAN J. Ni-Au alloy nanoparticles as a high performance heterogeneous catalyst for hydrogenation of aromatic nitro compounds [J]. Journal of Alloys and Compounds, 2019, 792: 286-290.

[39] TEGEDER P, FREITAG M, CHEPIGA K M,. N-heterocyclic carbene-modified Au-Pd alloy nanoparticles and their application as biomimetic and heterogeneous catalysts [J]. Chemistry-A European Journal, 2018, 24(70): 18682-18688.

[40] BUSTAMANTE T M, CAMPOS C H, FRAGA M A,. Promotional effect of palladium in Co-SiO2core@shell nanocatalysts for selective liquid phase hydrogenation of chloronitroarenes [J]. Journal of Catalysis, 2020, 385: 224-237.

[41] FURUKAWA S, TAKAHASHI K, KOMATSU T. Well-structured bimetallic surface capable of molecular recognition for chemoselective nitroarene hydrogenation [J]. Chemical Science, 2016, 7(7): 4476-4484.

[42] LI X, WANG Y, LI L Q,. Deficient copper decorated platinum nanoparticles for selective hydrogenation of chloronitrobenzene [J]. Journal of Materials Chemistry A, 2017, 5(22): 11294-11300.

[43] WU Q F, ZHANG C, LIN W W,. Selective hydrogenation of 3-nitrostyrene over a Co-promoted Pt catalyst supported on P-containing activated charcoal [J]. Catalysts, 2019, 9(5): 428.

[44] IIHAMA S, FURUKAWA S, KOMATSU T. Efficient catalytic system for chemoselective hydrogenation of halonitrobenzene to haloaniline using PtZn intermetallic compound [J]. ACS Catalysis, 2016, 6(2): 742-746.

[45] MAO J J, CHEN W X, SUN W M,. Rational control of the selectivity of a ruthenium catalyst for hydrogenation of 4-nitrostyrene by strain regulation [J]. Angewandte Chemie-International Edition, 2017, 56(39): 11971-11975.

[46] PEI Y C, QI Z Y, GOH T W,. Intermetallic structures with atomic precision for selective hydrogenation of nitroarenes [J]. Journal of Catalysis, 2017, 356: 307-314.

[47] HAN A J, ZHANG J, SUN W M,. Isolating contiguous Pt atoms and forming Pt-Zn intermetallic nanoparticles to regulate selectivity in 4-nitrophenylacetylene hydrogenation [J]. Nature Communications, 2019, 10: 3787.

[48] QIAO B T, WANG A Q, YANG X F,. Single-atom catalysis of Co oxidation using Pt-1/FeO[J]. Nature Chemistry, 2011, 3(8): 634-641.

[49] WEI H S, REN Y J, WANG A Q,. Remarkable effect of alkalis on the chemoselective hydrogenation of functionalized nitroarenes over high-loading P/FeOcatalysts [J]. Chemical Science, 2017, 8(7): 5126-5131.

[50] SHI X X, WANG X G, SHANG X F,. High performance and active sites of a ceria-supported palladium catalyst for solvent-free chemoselective hydrogenation of nitroarenes [J]. ChemCatChem, 2017, 9(19): 3743-3751.

[51] PENG Y H, GENG Z G, ZHAO S T,. Pt single atoms embedded in the surface of Ni nanocrystals as highly active catalysts for selective hydrogenation of nitro compounds [J]. Nano Letters, 2018, 18(6): 3785-3791.

[52] LIN L L, YAO S Y, GAO R,. A highly CO-tolerant atomically dispersed Pt catalyst for chemoselective hydrogenation [J]. Nature Nanotechnology, 2019, 14(4): 354-361.

[53] CHEN G X, XU C F, HUANG X Q,. Interfacial electronic effects control the reaction selectivity of platinum catalysts [J]. Nature Materials, 2016, 15(5): 564-569.

[54] WANG Y, QIN R X, WANG Y K,. Chemoselective hydrogenation of nitroaromatics at the nanoscale iron(III)-OH-platinum interface [J]. Angewandte Chemie-International Edition, 2020, 59(31): 12736-12740.

[55] GU J, ZHANG Z Y, HU P,. Platinum nanoparticles encapsulated in MFI zeolite crystals by a two-step dry gel conversion method as a highly selective hydrogenation catalyst [J]. ACS Catalysis, 2015, 5(11): 6893-6901.

[56] CHEN Q, WANG M Y, ZHANG C X,. Selectivity control on hydrogenation of substituted nitroarenes through end-on adsorption of reactants in zeolite-encapsulated platinum nanoparticles [J]. Chemistry-An Asian Journal, 2018, 13(16): 2077-2084.

[57] ZHANG J, WANG L, SHAO Y,. A Pd@zeolite catalyst for nitroarene hydrogenation with high product selectivity by sterically controlled adsorption in the zeolite micropores [J]. Angewandte Chemie-International Edition, 2017, 56(33): 9747-9751.

[58] YAN X R, CHEN L L, SONG H X,. Metal–organic framework (MOF)-derived catalysts for chemoselective hydrogenation of nitroarenes [J]. New Journal of Chemistry, 2021, 45(39):18268-18276.

[59] WESTERHAUS F A, JAGADEESH R V, WIENHOEFER G,. Heterogenized cobalt oxide catalysts for nitroarene reduction by pyrolysis of molecularly defined complexes [J]. Nature Chemistry, 2013, 5(6): 537-543.

[60] PISIEWICZ S, FORMENTI D, SURKUS A E,. Synthesis of nickel nanoparticles with N-doped graphene shells for catalytic reduction reactions [J]. ChemCatChem, 2016, 8(1): 129-134.

[61] JAGADEESH R V, SURKUS A E, JUNGE H,. Nanoscale Fe2O3-based catalysts for selective hydrogenation of nitroarenes to anilines [J]. Science, 2013, 342(6162): 1073-1076.

[62] FORMENTI D, FERRETTI F, TOPF C,. Co-based heterogeneous catalysts from well-defined alpha-diimine complexes: Discussing the role of nitrogen [J]. Journal of Catalysis, 2017, 351: 79-89.

[63] SAHOO B, FORMENTI D, TOPF C,. Biomass-derived catalysts for selective hydrogenation of nitroarenes [J]. ChemSusChem, 2017, 10(15): 3035-3039.

[64] WEI Z Z, WANG J, MAO S J,. In situ-generated Co-0-Co3O4/N-doped carbon nanotubes hybrids as efficient and chemoselective catalysts for hydrogenation of nitroarenes [J]. ACS Catalysis, 2015, 5(8): 4783-4789.

[65] CHEN P R, YANG F K, KOSTKA A,. Interaction of cobalt nanoparticles with oxygen- and nitrogen-functionalized carbon nanotubes and impact on nitrobenzene hydrogenation catalysis [J]. ACS Catalysis, 2014, 4(5): 1478-1486.

[66] CUI X L, LIANG K, TIAN M,. Cobalt nanoparticles supported on N-doped mesoporous carbon as a highly efficient catalyst for the synthesis of aromatic amines [J]. Journal of Colloid and Interface Science, 2017, 501: 231-240.

[67] ZHOU P, JIANG L, WANG F,. High performance of a cobalt-nitrogen complex for the reduction and reductive coupling of nitro compounds into amines and their derivatives [J]. Science Advances, 2017, 3(2): e1601945.

[68] BARAMOV T, LOOS P, HASSFELD J,. Encapsulated cobalt oxide on carbon nanotube support as catalyst for selective continuous hydrogenation of the showcase substrate 1-iodo-4-nitrobenzene [J]. Advanced Synthesis & Catalysis, 2016, 358(18): 2903-2911.

[69] MA X, ZHOU Y X, LIU H,. A mof-derived Co-CoO@N-doped porous carbon for efficient tandem catalysis: Dehydrogenation of ammonia borane and hydrogenation of nitro compounds [J]. Chemical Communications, 2016, 52(49): 7719-7722.

[70] YANG S L, PENG L, OVEISI E,. MOF-derived cobalt phosphide/carbon nanocubes for selective hydrogenation of nitroarenes to anilines [J]. Chemistry - A European Journal, 2018, 24(17): 4234-4238.

[71] YANG S L, PENG L, SUN D T,. Metal–organic-framework-derived Co3S4hollow nanoboxes for the selective reduction of nitroarenes [J]. ChemSusChem, 2018, 11(18): 3131-3138.

[72] WANG X, LI Y W. Chemoselective hydrogenation of functionalized nitroarenes using mof-derived Co-based catalysts [J]. Journal of Molecular Catalysis A-Chemical, 2016, 420: 56-65.

[73] HU A, LU X H, CAI D M,. Selective hydrogenation of nitroarenes over mof-derived Co@CN catalysts at mild conditions [J]. Molecular Catalysis, 2019, 472: 27-36.

[74] WANG H J, WANG Y, LI Y F,. Highly efficient hydrogenation of nitroarenes by N-doped carbon-supported cobalt single-atom catalyst in ethanol/water mixed solvent [J]. ACS Applied Materials & Interfaces, 2020, 12(30): 34021-34031.

[75] LAN X C, ALI B, WANG Y,. Hollow and yolk-shell Co-N-C@SiO2nanoreactors: Controllable synthesis with high selectivity and activity for nitroarene hydrogenation [J]. ACS Applied Materials & Interfaces, 2020, 12(3): 3624-3630.

[76] SUN X, OLIVOS-SUAREZ A I, OSADCHII D,. Single cobalt sites in mesoporous N-doped carbon matrix for selective catalytic hydrogenation of nitroarenes [J]. Journal of Catalysis, 2018, 357: 20-28.

[77] LI M H, CHEN S Y, JIANG Q K,. Origin of the activity of Co-N-C catalysts for chemoselective hydrogenation of nitroarenes [J]. ACS Catalysis, 2021, 11(5): 3026-3039.

[78] SORRIBES I, LIU L C, CORMA A. Nanolayered Co-Mo-S catalysts for the chemoselective hydrogenation of nitroarenes [J]. ACS Catalysis, 2017, 7(4): 2698-2708.

[79] ZHANG G J, TANG F Y, WANG X Y,. Co,N-codoped porous carbon-supported coyzns with superior activity for nitroarene hydrogenation [J]. ACS Sustainable Chemistry & Engineering, 2020, 8(15): 6118-6126.

[80] LU C S, LV J H, MA L,. Highly selective hydrogenation of halonitroaromatics to aromatic haloamines by ligand modified Ni-based catalysts [J]. Chinese Chemical Letters, 2012, 23(5): 545-548.

[81] LIU X, MA X X, LIU S J,. Metal fluoride promoted catalytic hydrogenation of aromatic nitro compounds over Raney?Ni [J]. RSC Advances, 2015, 5(46): 36423-36427.

[82] LI H, ZHANG J, LI H X. Ultrasound-assisted preparation of a novel Ni-B amorphous catalyst in uniform nanoparticles for-chloronitrobenzene hydrogenation [J]. Catalysis Communications, 2007, 8(12): 2212-2216.

[83] LI H, ZHAO Q F, LI H X. Selective hydrogenation of-chloronitrobenzene over Ni-P-B amorphous catalyst and synergistic promoting effects of B and P [J]. Journal of Molecular Catalysis A-Chemical, 2008, 285(1-2): 29-35.

[84] HAHN G, EWERT J K, DENNER C,. A reusable mesoporous nickel nanocomposite catalyst for the selective hydrogenation of nitroarenes in the presence of sensitive functional groups [J]. ChemCatChem, 2016, 8(15): 2461-2465.

[85] QU Y M, YANG H, WANG S L,. Hydrogenation of nitrobenzene to aniline catalyzed by C60-stabilized Ni [J]. Catalysis Communications, 2017, 97: 83-87.

[86] LU X H, WEI X L, ZHOU D,. Synthesis, structure and catalytic activity of the supported Ni catalysts for highly efficient one-step hydrogenation of 1,5-dinitronaphthalene to 1,5-diaminodecahydronaphthalene [J]. Journal of Molecular Catalysis A-Chemical, 2015, 396: 196-206.

[87] LI Y Z, YU J Y, LI W,. The promotional effect of surface defects on the catalytic performance of supported nickel-based catalysts [J]. Physical Chemistry Chemical Physics, 2016, 18(9): 6548-6558.

[88] REN Y J, WEI H S, YIN G Z,. Oxygen surface groups of activated carbon steer the chemoselective hydrogenation of substituted nitroarenes over nickel nanoparticles [J]. Chemical Communications, 2017, 53(12): 1969-1972.

[89] HUANG L, LV Y, LIU S,. Non-noble metal Ni nanoparticles supported on highly dispersed TiO2-modified activated carbon as an efficient and recyclable catalyst for the hydrogenation of halogenated aromatic nitro compounds under mild conditions [J]. Industrial & Engineering Chemistry Research, 2020, 59(4): 1422-1435.

[90] HUANG H G, WANG X G, SHENG Y,. Nitrogen-doped graphene-activated metallic nanoparticle-incorporated ordered mesoporous carbon nanocomposites for the hydrogenation of nitroarenes [J]. RSC Advances, 2018, 8(16): 8898-8909.

[91] DUTTA D, DUTTA D K. Selective and efficient hydrogenation of halonitrobenzene catalyzed by clay supported Ni-O-nanoparticles [J]. Applied Catalysis A-General, 2014, 487: 158-164.

[92] XIONG W, WANG L P, CAI G X,. Nitrogen-functionalized active carbon-supported non-noble nickel nanoparticles with high dispersity and enhanced catalytic performance in nitro naphthalene hydrogenation [J]. ChemistrySelect, 2017, 2(34): 11244-11249.

[93] ADVANI J H, RAVI K, NAIKWADI D R,. Bio-waste chitosan-derived N-doped cnt-supported Ni nanoparticles for selective hydrogenation of nitroarenes [J]. Dalton Transactions, 2020, 49(30): 10431-10440.

[94] RYABCHUK P, AGOSTINI G, POHL M M,. Intermetallic nickel silicide nanocatalyst-A non-noble metal-based general hydrogenation catalyst [J]. Science Advances, 2018, 4(6): eaat0761.

[95] CHEN J, YAO Y, ZHAO J,. A highly active non-precious metal catalyst based on Fe-N-C@CNTs for nitroarene reduction [J]. RSC Advances, 2016, 6(98): 96203-96209.

[96] XU S D, YU D Q, LIAO S F,. Nitrogen-doped carbon supported iron oxide as efficient catalysts for chemoselective hydrogenation of nitroarenes [J]. RSC Advances, 2016, 6(98): 96431-96435.

[97] WANG Y Y, SHI J J, ZHANG Z H,. Carbon film encapsulated Fe2O3: An efficient catalyst for hydrogenation of nitroarenes [J]. Chinese Journal of Catalysis, 2017, 38(11): 1909-1917.

[98] NIU H L, LU J H, SONG J J,. Iron oxide as a catalyst for nitroarene hydrogenation: Important role of oxygen vacancies [J]. Industrial & Engineering Chemistry Research, 2016, 55(31): 8527-8533.

[99] JAGADEESH R V, STEMMLER T, SURKUS A E,. Hydrogenation using iron oxide-based nanocatalysts for the synthesis of amines [J]. Nature Protocols, 2015, 10(4): 548-557.

[100] SHI J J, WANG Y Y, DU W C,. Synthesis of graphene encapsulated Fe3C in carbon nanotubes from biomass and its catalysis application [J]. Carbon, 2016, 99: 330-337.

[101] MA B, TONG X L, GUO C X,. Pyrite nanoparticles: An earth-abundant mineral catalyst for activation of molecular hydrogen and hydrogenation of nitroaromatics [J]. RSC Advances, 2016, 6(60): 55220-55224.

[102] MORSE J R, CALLEJAS J F, DARLING A J,. Bulk iron pyrite as a catalyst for the selective hydrogenation of nitroarenes [J]. Chemical Communications, 2017, 53(35): 4807-4810.

[103] ZHU Y A, YANG S L, CAO C Y,. Controllable synthesis of carbon encapsulated iron phosphide nanoparticles for the chemoselective hydrogenation of aromatic nitroarenes to anilines [J]. Inorganic Chemistry Frontiers, 2018, 5(5): 1094-1099.

[104] DUAN Y N, DONG X S, SONG T,. Hydrogenation of functionalized nitroarenes catalyzed by single-phase pyrite FeS2nanoparticles on N,S-codoped porous carbon [J]. ChemSusChem, 2019, 12(20): 4636-4644.

[105] YE T N, LU Y F, LI J,. Copper-based intermetallic electride catalyst for chemoselective hydrogenation reactions [J]. Journal of the American Chemical Society, 2017, 139(47): 17089-17097.

[106] KOUR G, GUPTA M, VISHWANATHAN B,. (Cu/NCNTs): A new high temperature technique to prepare a recyclable nanocatalyst for four component pyridine derivative synthesis and nitroarenes reduction [J]. New Journal of Chemistry, 2016, 40(10): 8535-8542.

[107] NI T, ZHANG S, CAO F X,. NiCo bimetallic nanoparticles encapsulated in graphite-like carbon layers as efficient and robust hydrogenation catalysts [J]. Inorganic Chemistry Frontiers, 2017, 4(12): 2005-2011.

[108] SERNA P, CORMA A. Transforming nano metal nonselective particulates into chemoselective catalysts for hydrogenation of substituted nitrobenzenes [J]. ACS Catalysis, 2015, 5(12): 7114-7121.

[109] LIU L C, GAO F, CONCEPCION P,. A new strategy to transform MoO and bimetallic non-noble metal nanoparticles into highly active and chemoselective hydrogenation catalysts [J]. Journal of Catalysis, 2017, 350: 218-225.

[110] HAN B H, SHIN D H, CHO S Y. Graphite catalyzed reduction of aromatic and aliphatic nitro-compounds with hydrazine hydrate [J]. Tetrahedron Letters, 1985, 26(50): 6233-6234.

[111] SCHIMMEL H G, KEARLEY G J, NIJKAMP M G,. Hydrogen adsorption in carbon nanostructures: Comparison of nanotubes, fibers, and coals [J]. Chemistry-A European Journal, 2003, 9(19): 4764-4770.

[112] CHEN X H, SHEN Q J, LI Z J,. Metal-free h-2 activation for highly selective hydrogenation of nitroaromatics using phosphorus-doped carbon nanotubes [J]. ACS Applied Materials & Interfaces, 2020, 12(1): 654-666.

[113] SHANG S S, GAO S. Heteroatom-enhanced metal-free catalytic performance of carbocatalysts for organic transformations [J]. ChemCatChem, 2019, 11(16): 3728-3742.

[114] PRIMO A, NEATU F, FLOREA M,. Graphenes in the absence of metals as carbocatalysts for selective acetylene hydrogenation and alkene hydrogenation [J]. Nature Communications, 2014, 5: 5291.

[115] LUO Z C, NIE R F, NGUYEN V T,. Transition metal-like carbocatalyst [J]. Nature Communications, 2020, 11(1): 4091.

[116] GAO R J, PAN L, LU J H,. Phosphorus-doped and lattice-defective carbon as metal-like catalyst for the selective hydrogenation of nitroarenes [J]. ChemCatChem, 2017, 9(22): 4287-4294.

[117] CHEN P R, CHEW L M, XIA W. The influence of the residual growth catalyst in functionalized carbon nanotubes on supported Pt nanoparticles applied in selective olefin hydrogenation [J]. Journal of Catalysis, 2013, 307: 84-93.

[118] WU S C, WEN G D, WANG J,. Nitrobenzene reduction catalyzed by carbon: Does the reaction really belong to carbocatalysis? [J]. Catalysis Science & Technology, 2014, 4(12): 4183-4187.

[119] LI B J, XU Z. A nonmetal catalyst for molecular hydrogen activation with comparable catalytic hydrogenation capability to noble metal catalyst [J]. Journal of the American Chemical Society, 2009, 131(45): 16380-16382.

[120] PACOSOVA L, KARTUSCH C, KUKULA P,. Is fullerene a nonmetal catalyst in the hydrogenation of nitrobenzene? [J]. ChemCatChem, 2011, 3(1): 154-156.

Progress on catalysts for selective hydrogenation of nitroarenes

ZHANG Yuan-yuan1,2, CHEN Jing-wen1,2, LU Dan1,2, BAO Zong-bi1,2, YANG Qi-wei1,2,YANG Yi-wen1,2, ZHANG Zhi-guo1,2

(1. Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China;2. Institute of Zhejiang University-Quzhou, Quzhou 324000, China)

Aniline derivatives are important intermediates of fine chemicals, which are generally prepared by catalytic hydrogenation of nitroarenes in industry. However, it is challenging to selectively hydrogenate nitro group when nitroarenes bear halogen or other reducible functional groups. Therefore, the development of selective hydrogenation catalysts becomes critical. This review summarizes recent advances of these catalysts with emphasis on heterogeneous catalytic systems and catalyst modification strategies including noble metal catalysts, non-noble metal catalysts and metal-free carbon catalysts. Selective hydrogenation performance of some catalysts for different nitroarenes are summarized. Latest and future development are introduced.

nitroarenes; aromatic amine compounds; selective catalytic hydrogenation; hydrogen

1003-9015(2022)04-0459-14

TQ032

A

10.3969/j.issn.1003-9015.2022.04.001

2021-04-20；

2021-05-21。

國(guó)家自然科學(xué)基金(22078288, 21878266)；國(guó)家重點(diǎn)研發(fā)計(jì)劃(2016YFA0202900)。

張媛媛(1996-)，女，浙江溫州人，浙江大學(xué)碩士生。

張治國(guó)，E-mail：zhiguo.zhang@zju.edu.cn

張媛媛, 陳靜雯, 盧丹, 鮑宗必, 楊啟煒, 楊亦文, 張治國(guó). 硝基芳烴選擇性加氫催化劑的研究進(jìn)展[J]. 高?；瘜W(xué)工程學(xué)報(bào), 2022, 36(4): 459-472.

：ZHANG Yuan-yuan,CHEN Jing-wen,LU Dan,BAO Zong-bi,YANG Qi-wei, YANG Yi-wen,ZHANG Zhi-guo. Progress on catalysts for selective hydrogenation of nitroarenes [J]. Journal of Chemical Engineering of Chinese Universities, 2022, 36(4): 459-472.