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A MoS_2 nanocatalyst with surface-enriched active sites for the heterogeneous transfer hydrogenation of nitroarenes
表面暴露活性位点的MoS_2纳米催化剂催化硝基化合物的非均相氢转移反应

Wang Jia ^1,2 Zhang Yajie ^1,3 Diao Jiangyong ¹ Zhang Jiayun ^1,3 Liu Hongyang ¹ ^* Su Dangsheng ^1,4 ^*

文摘	A highly efficient and reusable plane-curved and interlayer-expanded MoS_2 nanocatalyst with increased exposure of active sites was prepared. The catalyst was used for the heterogeneous hydrogen transfer reaction of nitroarenes with hydrazine monohydrate as a reductant under mild reaction conditions without pressure and base, which was different from other hydrogen transfer systems that require the presence of a base (e.g., propan-2-ol/KOH). The sandwiching of carbon between the MoS_2 nanosheets increased the distance between the layers of MoS_2 and exposed more Mo sites, resulting in superior catalytic performance compared with that of bulk MoS_2 catalyst. The active hydrogen (H~*) generated from N_2H_4 could directly transfer to the –NO_2 groups of nitrobenzene to form aniline followed by N_2 emission, which was confirmed by detecting the gas emission with mass spectrometry during the decomposition of hydrazine or the co-existence of nitrobenzene and hydrazine.
其他语种文摘	MoS_2具有独特的二维层状结构,被广泛用于加氢脱硫过程以及HER反应,而且可以通过减少MoS_2的颗粒尺寸以及层数来进一步改善其催化活性.通过剥离方法得到的MoS_2纳米片虽然表现出优良的加氢脱硫活性,但容易团聚使其循环使用性能很差.如果通过引入纳米碳将单层的MoS_2纳米片进行有效“隔离”,则可明显降低团聚的可能性,从而改善其催化性能和稳定性.本文通过一步水热法制备出了碳嵌入的MoS_2纳米颗粒(MoS_2@C),将其应用于硝基苯类化合物的氢转移反应中表现出了非常好的催化性能.进一步通过粉末X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和在线质谱检测等手段研究了层间距增加的MoS_2催化剂在硝基苯类化合物的氢转移反应中催化性能提升的原因. XRD, SEM和TEM结果表明,通过引入碳材料可以明显增加MoS_2的层间距,同时减小其颗粒尺寸,而且使MoS_2表现出弯曲的(002)晶面.由于存在一定的曲率,这种(002)晶面也会表现出一定的催化能力.氮气物理吸附结果表明,这种MoS_2@C复合物具有较高的比表面积(89 m~2 g~(–1))和明显的介孔结构(~20 nm),在催化反应中有利于底物扩散,进而改善催化性能. XPS结果显示,与体相的MoS_2相比, MoS_2@C表面暴露出更多的不饱和Mo原子(Mo/S= 0.71(MoS_2@C) vs Mo/S= 0.63(MoS_2)),形成了独特的S-Mo-O结构以及缺陷结构.在硝基苯类化合物的氢转移反应中,层间距增加的MoS_2@C由于暴露出更多的活性位和具有弯曲的(002)晶面,表现出了更高的催化活性(TOF= 3.66 s–1 vs 1.24 s–1(MoS_2)).通过质谱对反应过程的追踪发现,在只有肼存在的条件下, MoS_2@C催化肼分解的主要气相产物是氨气.这说明MoS_2@C能够使肼发生N–N键的断裂.而当肼和硝基苯同时存在的条件下,质谱检测的气相产物主要是氮气,表明硝基苯的存在可以诱导肼逐步发生N–H键断裂,在催化剂表面形成活性的H物种,进而转移到硝基苯上使其还原得到苯胺.使用偶氮苯和氧化偶氮苯作为反应底物,发现MoS_2@C很难使其还原为苯胺,这说明在该催化体系中,硝基苯的还原过程主要是沿着直接路径(硝基苯-亚硝基苯-苯胺)进行的.
来源	催化学报 ,2018,39(1):79-87 【核心库】
DOI	10.1016/S1872-2067(17)62925-5
关键词	Molybdenum disulfide ; Interlayer expansion ; Hydrogen transfer reaction ; Nitrobenzene reduction ; Alkali-free
地址	1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang National Laboratory for Materials Science, Liaoning, Shenyang, 110016 2. Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, State Key Laboratory for Oxo Synthesis and Selective Oxidation, Gansu, Lanzhou, 730000 3. School of Materials Science and Engineering, University of Science and Technology of China, Liaoning, Shenyang, 110016 4. Energy Research Resources Division, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Liaoning, Dalian, 116023
语种	英文
文献类型	研究性论文
ISSN	0253-9837
学科	化学
基金	the Youth Innovation Promotion Association (CAS), and the Sinopec China ; 国家自然科学基金 ; supported by the Ministry of Science and Technology (MOST)
文献收藏号	CSCD:6160937

参考文献共 46 共3页

引证文献 5 篇

1 Jing Pei Synergism of Pt nanoparticles and iron oxide support for chemoselective hydrogenation of nitroarenes under mild conditions 催化学报,2019,40(2):214-222
CSCD被引 3 次

2 王嘉氮掺杂碳包覆金属催化剂的制备及其在多相催化反应中的应用中国科学. 化学,2018,48(12):1587-1602
CSCD被引 2 次

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A MoS_2 nanocatalyst with surface-enriched active sites for the heterogeneous transfer hydrogenation of nitroarenes 表面暴露活性位点的MoS_2纳米催化剂催化硝基化合物的非均相氢转移反应

A MoS_2 nanocatalyst with surface-enriched active sites for the heterogeneous transfer hydrogenation of nitroarenes
表面暴露活性位点的MoS_2纳米催化剂催化硝基化合物的非均相氢转移反应