Nitrogen-Induced Strong Metal–Support Interaction over Ru/CeO ₂ Catalysts for CO ₂ Hydrogenation

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/CeO 2 catalysts by simply altering the precursor types of supported Ru species. Under the same preparation conditions, when using Ru(NO)(NO 3 ) 3 as the precursor (Ru(N)/CeO 2 ), the residual N species located at the Ru–N–Ce interfaces weaken the Ce–O bonds in ceria, promoting the surface migration of CeO 2– x species to generate SMSI together with increasing surface oxygen vacancy concentrations, whereas this process does not occur when RuCl 3 is employed (Ru(Cl)/CeO 2 ). Catalytic performance of the Ru/CeO 2 catalysts in CO 2 hydrogenation sensitively depends on the structures of the supported Ru species. The Ru(Cl)/CeO 2 catalyst with exposed Ru atoms exhibits better H 2 activation and H-spillover capacities, efficiently driving CO 2 hydrogenation to CH 4 via combined Mars–van Krevelen (MvK) and H 2 -assisted associated mechanisms. However, the hydrogenation process is seriously impeded over the Ru(N)/CeO 2 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 CO 2 conversion via the SMSI effect.