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

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-SiW 12 O 40 4- (RSTA) as an inorganic ligand to mediate Co 3 O 4 nanoparticles that efficiently promote the hydrolysis of NaBH 4 to generate hydrogen with multiple activities (4747 mL/(g cat ·min)) compared with NaBH 4 -pretreated Co 3 O 4 (1236 mL/(g cat ·min)), pristine Co 3 O 4 (inactive) and commercial Co 3 O 4 (inactive) at 25℃. RSTA induced both electronic and morphology effects on Co 3 O 4 through in situ driving 3D Co 3 O 4 nanoparticles to 2D Co 3 O 4 nanosheets with rich surface oxygen vacancies or Co 2+ during the hydrolysis process. This modulation by RSTA allowed more active sites, including both electron-rich Co 0 and electron-deficient Co 2+ , facilitating BH 4 - and H 2 O adsorption and thus hydrogen generation. The promoted mechanism of the RSTA on both the microstructure and the catalytic performance was further proposed.