Ir Single Atoms and Clusters Supported on Î±-MoC as Catalysts for Efficient Hydrogenation of CO<sub>2</sub> to CO

doi:10.3866/PKU.WHXB202302021

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	Ir Single Atoms and Clusters Supported on Î±-MoC as Catalysts for Efficient Hydrogenation of CO₂ to CO
	Lu, Junwen 1,2; Zhang, Shunan3 ; Zhou, Haozhi3 ; Huang, Chaojie 1,2; Xia, Lin 1; Liu, Xiaofang 1; Luo, Hu 1; Wang, Hui1,3
	2023-06-27
发表期刊	ACTA PHYSICO-CHIMICA SINICA (IF:10.8[JCR-2023],5.5[5-Year])
ISSN	1000-6818
卷号	39 期号:11
发表状态	已发表
DOI	10.3866/PKU.WHXB202302021
摘要	The conversion of CO2 into CO via the reverse water gas shift (RWGS) reaction has recently attracted considerable attention owing to the increase in atmospheric CO2 emissions. However, metal supported catalysts easily undergo sintering and become inactive at high temperatures. To fabricate highly active and stable catalysts, molybdenum carbide (MoxC), with properties similar to those of precious metals, has been extensively investigated. In particular, it has been demonstrated that face-centered cubic alpha-MoC can strongly interact with support metals, rendering it an attractive candidate as a catalyst for the RWGS reaction. Furthermore, it has been previously demonstrated that metallic Ir, with unique electronic properties and a low CO desorption barrier, is active for the RWGS at low temperatures (250-300 degrees C). Accordingly, in this study, a system of Ir species and alpha-MoC was constructed using a solvent evaporation self-assembly method. The catalytic performance of the Ir/MoC catalysts for the RWGS reaction was considerably superior to that of pure alpha-MoC over a wide temperature range (200-500 degrees C) owing to the synergistic effect of Ir and alpha-MoC. The optimal 0.5%Ir/MoC catalyst yielded a CO2 conversion of 48.4% at 500 degrees C, 0.1 MPa, and 300000 mLg(-1)h(-1), which was comparable to the equilibrium conversion (49.9%). The CO selectivity and spacetime yield of CO over 0.5%Ir/MoC reached 94.0% and 423.1 mu molg(-1)s(-1), respectively, which were higher than most of the previously reported values. Moreover, 0.5%Ir/MoC retained its catalytic properties over 100 h and demonstrated excellent stability at high temperatures. Several characterization methods were used to demonstrate that the Ir species supported on alpha-MoC substrates were highly dispersed. The strong metal-support interaction between Ir and alpha-MoC, which occurred via electron transfer, considerably improved the stability of the Ir/MoC catalysts. For the Ir/MoC catalysts with Ir loadings > 0.2 wt% (wt%: mass fraction), Ir single atoms (Ir-1) and clusters (Ir-n) coexisted to create Ir-n-Ir-1-C-Mo synergistic sites between Ir and alpha-MoC. The number of Ir-1 species and size of Ir-n species of 0.5%Ir/MoC were higher and smaller, respectively, than those of the other Ir/MoC catalysts. This conferred 0.5%Ir/MoC an optimal electron density, which contributed to the remarkable adsorption and activation of CO2 and H-2 during the RWGS. In situ diffuse reflectance infrared Fourier transform spectroscopy experiments revealed that the RWGS reaction mechanism occurred via a formate pathway. Although the formation of Ir-n-Ir-1-C-Mo synergistic sites did not affect the reaction mechanism, the generation and decomposition of formate intermediates were distinctly promoted. Therefore, the catalytic performance of Ir/MoC was effectively improved by the synergistic effect. This study provides a guide for designing efficient and stable catalysts for CO2 utilization.
关键词	Reverse water gas shift reaction SMSI Synergistic effect Molybdenum carbides Iridium catalyst
URL	查看原文
收录类别	SCI ; 北大核心 ; CSCD
语种	英语
资助项目	National Key Research and Development Program of China["2022YFA1504800","2022YFA1504702","2022YFB4101900"] ; National Natural Science Foundation of China["22108289","22279158","21905291"] ; CNOOC Institute of Chemicals & Advanced Materials, China[YJSCZX07956YJ] ; Shanghai Institute of Cleantech Innovation, China[E244831E01]
WOS研究方向	Chemistry
WOS类目	Chemistry, Physical
WOS记录号	WOS:001078886500004
出版者	PEKING UNIV PRESS
引用统计	正在获取...
文献类型	期刊论文
条目标识符	https://kms.shanghaitech.edu.cn/handle/2MSLDSTB/343586
专题	2060研究院_公共科研平台_低碳转化利用系统研究组物质科学与技术学院_博士生 2060研究院
通讯作者	Zhang, Shunan; Wang, Hui
作者单位	1.Chinese Acad Sci, Shanghai Adv Res Inst, CAS Key Lab Low Carbon Convers Sci & Engn, Shanghai 201210, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.ShanghaiTech Univ, Inst Carbon Neutral, Shanghai 201203, Peoples R China
通讯作者单位	2060研究院
推荐引用方式 GB/T 7714	Lu, Junwen,Zhang, Shunan,Zhou, Haozhi,et al. Ir Single Atoms and Clusters Supported on Î±-MoC as Catalysts for Efficient Hydrogenation of CO₂ to CO[J]. ACTA PHYSICO-CHIMICA SINICA,2023,39(11).
APA	Lu, Junwen.,Zhang, Shunan.,Zhou, Haozhi.,Huang, Chaojie.,Xia, Lin.,...&Wang, Hui.(2023).Ir Single Atoms and Clusters Supported on Î±-MoC as Catalysts for Efficient Hydrogenation of CO₂ to CO.ACTA PHYSICO-CHIMICA SINICA,39(11).
MLA	Lu, Junwen,et al."Ir Single Atoms and Clusters Supported on Î±-MoC as Catalysts for Efficient Hydrogenation of CO₂ to CO".ACTA PHYSICO-CHIMICA SINICA 39.11(2023).