In situ transformation of 3D Co3O4 nanoparticles to 2D nanosheets with rich surface oxygen vacancies to boost hydrogen generation from NaBH4

Abstract

Despite substantial progress in various application fields of polyoxometalates (POMs), the use of POMs as ligands to alter the structure of solid catalysts in heterogeneous catalysis requires additional efforts. Herein, we used the reduced α-SiW12O404- (RSTA) as an inorganic ligand to mediate Co3O4 nanoparticles that efficiently promote the hydrolysis of NaBH4 to generate hydrogen with multiple activities (4747 mL/(gcat·min)) compared with NaBH4-pretreated Co3O4 (1236 mL/(gcat·min)), pristine Co3O4 (inactive) and commercial Co3O4 (inactive) at 25℃. RSTA induced both electronic and morphology effects on Co3O4 through in situ driving 3D Co3O4 nanoparticles to 2D Co3O4 nanosheets with rich surface oxygen vacancies or Co2+ during the hydrolysis process. This modulation by RSTA allowed more active sites, including both electron-rich Co0 and electron-deficient Co2+, facilitating BH4- and H2O adsorption and thus hydrogen generation. The promoted mechanism of the RSTA on both the microstructure and the catalytic performance was further proposed.