Surface Borate-Derived Highly Dispersed and Stable Metal Nanoparticles on Nitrogen-Vacancy Boron Nitride Support Promoting CO Methanation

Constructing and regulating the metal-support interaction by the surface defects of support have emerged as a promising approach to optimizing the catalytic performance on hexagonal boron nitride (h-BN)-supported metal catalysts. Here, we report highly dispersed and stable nickel nanoparticles derived from the strongly interacted surface nickel borate species with nitrogen-vacancy-rich h-BN (mBN) support for promoting CO methanation catalysis. Experimental and characterization results reveal that the strong interaction between mBN support and Ni species originates from the in situ generated amorphous surface nickel borate species during the air calcination process. These surface nickel borate species are reduced to highly dispersed Ni nanoparticles with partial coverage of BOx species. After the in situ removal of BOx species at the surface of Ni nanoparticles during the induction period, also evidenced by the in situ water vapor pretreatment of the Ni/mBN experiment, the CO conversion increases from 37 to 96% and maintained stable for 100 h in the CO methanation over the as-prepared Ni/mBN catalyst. The strategy of in situ architecting surface metal borate intermediates on the supports could provide an important toolkit in the design of dispersed and stable supported metal catalysts.