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

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 (Ni^δ−) species. At the interfacial sites on Ni/CeO₂-BN, the synergy between oxygen vacancies and Ni^δ−, 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.