Tailoring metal-support interactions via spatial confinement of Ni/CeO2 interfaces on h-BN for efficient CO2 methanation

Abstract

Modulating metal-support interactions is critical for improving catalytic activity and product selectivity for CO2 hydrogenation. Such modulation can be achieved by modifying the metal nanoparticles as well as the supports. Here, we prepared a novel catalyst, in which Ni nanoparticles were dispersed on CeO2 and hexagonal boron nitride (h-BN) hybrid supports. The introduction of h-BN to Ni/CeO2-BN effectively improves the dispersion of Ni nanoparticles. More importantly, the abundant Ni-CeO2 interfacial sites with enriched oxygen vacancies are formed over h-BN edge sites. The dispersed Ni species are anchored on CeO2 via a unique interfacial structure, with electron-rich Ni (Niδ−) species. At the interfacial sites on Ni/CeO2-BN, the synergy between oxygen vacancies and Niδ−, which enhances CO2 activation and H2 dissociation, respectively, renders superior catalytic performance for CO2 methanation. In situ DRIFTS suggests formate as key rate-limiting intermediates on Ni-CeO2 sites, while the formation of B-H bonds further promotes hydrogen activation and subsequently the catalytic performance. The modulation of metal-support interactions by spatial confinement effect by BN offers a new paradigm for designing metal/oxide catalysts for chemical transformations that requires bifunctionality as CO2 hydrogenation.