Grain boundaries modulating active sites in RhCo porous nanospheres for efficient CO2 hydrogenation  

作　　者：Xusheng Zheng Yue Lin Haibin Pan Lihui Wu Wei Zhang Linlin Cao Jing Zhang Lirong Zheng Tao Yao 

机构地区：[1]National Synchrotron Radiation Laboratory, University of Sdence and Technology of China, Hefei 230029,China [2]Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China [3]Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China

出　　处：《Nano Research》2018年第5期2357-2365,共9页纳米研究（英文版）

基　　金：This work was financially supported by the National Key Research and Development Program of China （No. 2017YFA0208300）, the National Natural Science Foundation of China （Nos. 11505187, 11404314, 11422547, 21471143, and 51676178） and the Fundamental Research Funds for the Central Universities （Nos. WK2310000066, WK2310000050, WK2340000076, and KY2310000019）, and Youth Innovation Promotion Association CAS （Nos. CX2310000054 and CX2310000091）. We also thank the beamline 1W1B at the Beijing Synchrotron Radiation Facility and the Beamline BL14W1 at Sh~anghai Synchrotron Radiation Facility for help in characterizations.

摘　　要：Designing active sites and engineering electronic properties of heterogeneous catalysts are both promising strategies that can be employed to enhance the catalytic activity for CO2 hydrogenation. Herein, we report RhCo porous nanospheres with a high density of accessible grain boundaries as active sites for improved catalytic performance in the hydrogenation of CO2 to methanol. The porous nanosphere morphological feature allows for a high population of grain boundaries to be accessible to the reactants, thereby providing sufficient active sites for the catalytic reaction. Moreover, in-situ X-ray photoelectron spectroscope （XPS） results revealed the creation of negatively charged Rh surface atoms that promoted the activation of CO2 to generate CO2^6- and methoxy intermediates. The obtained RhCo porous nanospheres exhibited remarkable low-temperature catalytic activity with a turnover frequency （TOFRh） of 612 h^-1, which was 6.1 and 2.5 times higher than that of Rh/C and RhCo nanoparticles, respectively. This work not only develops an efficient catalyst for CO2 hydrogenation, but also demonstrates a potential approach for the modulation of active sites and electronic properties.Designing active sites and engineering electronic properties of heterogeneous catalysts are both promising strategies that can be employed to enhance the catalytic activity for CO2 hydrogenation. Herein, we report RhCo porous nanospheres with a high density of accessible grain boundaries as active sites for improved catalytic performance in the hydrogenation of CO2 to methanol. The porous nanosphere morphological feature allows for a high population of grain boundaries to be accessible to the reactants, thereby providing sufficient active sites for the catalytic reaction. Moreover, in-situ X-ray photoelectron spectroscope （XPS） results revealed the creation of negatively charged Rh surface atoms that promoted the activation of CO2 to generate CO2^6- and methoxy intermediates. The obtained RhCo porous nanospheres exhibited remarkable low-temperature catalytic activity with a turnover frequency （TOFRh） of 612 h^-1, which was 6.1 and 2.5 times higher than that of Rh/C and RhCo nanoparticles, respectively. This work not only develops an efficient catalyst for CO2 hydrogenation, but also demonstrates a potential approach for the modulation of active sites and electronic properties.

关 键 词：carbon dioxide RHODIUM COBALT grain boundaries charge transfer HYDROGENATION 

分 类 号：O613.71[理学—无机化学] O643.36[理学—化学]