Grain boundaries modulating active sites in RhCo porous nanospheres for efficient CO2 hydrogenation
carbon dioxide, rhodium, cobalt, grain boundaries, charge transfer, hydrogenation
ABSTRACT 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 CO2δ– 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.
Tsinghua University Press
Xusheng Zheng,Yue Lin,Haibin Pan,Lihui Wu,Wei Zhang,Linlin Cao,Jing Zhang,Lirong Zheng,Tao Yao, Grain boundaries modulating active sites in RhCo porous nanospheres for efficient CO2 hydrogenation. NanoRes.2018, 11(5): 2357–2365