Amorphous Co2B loaded on a biochar-g-C3N4 composite as a versatile catalyst in both the conventional and the photo-assisted catalytic hydrolysis of sodium borohydride

A biochar-incorporated g-C 3 N 4 composite was obtained by co-calcining the mixture of spent coffee grounds and melamine and used to anchor highly dispersed amorphous cobalt boride nanoparticles via an impregnation-reduction method. The as-prepared Co 2 B/BC-g-C 3 N 4 was applied to the catalytic hydrolysis of sodium borohydride to produce hydrogen . The physicochemical properties of Co 2 B/BC, Co 2 B/g-C 3 N 4 , and Co 2 B/BC-g-C 3 N 4 were evaluated by various techniques to help elucidate the effect of the composite structure on the performance of Co 2 B/BC-g-C 3 N 4 . The Co 2 B/BC-g-C 3 N 4 exhibits much better activity than Co 2 B/BC and Co 2 B/g-C 3 N 4 because of a synergistic effect between the biochar and g-C 3 N 4 . In addition, the reaction kinetics can be improved by exposing the reaction system to visible light irradiation, yielding a hydrogen generation rate of 10.3 L min −1 g Co −1 in comparison to that of 9.1 L min −1 g Co −1 under darkness. The possible mechanism of the H 2 generation from the catalytic hydrolysis of sodium borohydride over Co 2 B/BC-g-C 3 N 4 under visible light irradiation was proposed. This work highlights the potential application of biochar-incorporated g-C 3 N 4 composite in synthesizing metallic catalysts and their practical use for photo-assisted catalytic hydrolysis of sodium borohydride .