Strong metal–support interaction (SMSI) is not only a fundamental concept in heterogeneous catalysis but also emerging as an effective strategy for designing advanced catalysts. Here, we present a facile approach to construct an SMSI over Ru/CeO2 catalysts by simply altering the precursor types of supported Ru species. Under the same preparation conditions, when using Ru(NO)(NO3)3 as the precursor (Ru(N)/CeO2), the residual N species located at the Ru–N–Ce interfaces weaken the Ce–O bonds in ceria, promoting the surface migration of CeO2–x species to generate SMSI together with increasing surface oxygen vacancy concentrations, whereas this process does not occur when RuCl3 is employed (Ru(Cl)/CeO2). Catalytic performance of the Ru/CeO2 catalysts in CO2 hydrogenation sensitively depends on the structures of the supported Ru species. The Ru(Cl)/CeO2 catalyst with exposed Ru atoms exhibits better H2 activation and H-spillover capacities, efficiently driving CO2 hydrogenation to CH4 via combined Mars–van Krevelen (MvK) and H2-assisted associated mechanisms. However, the hydrogenation process is seriously impeded over the Ru(N)/CeO2 catalyst with encapsulated Ru structures, resulting in the CO production through an MvK mechanism. This finding offers an innovative approach for tailoring catalyst structures for targeted CO2 conversion via the SMSI effect.
Dang et al. (Tue,) studied this question.