Decorating CdS with cobaltous hydroxide and graphene dual cocatalyst for photocatalytic hydrogen production coupled selective benzyl alcohol oxidation

Coupling photocatalytic H2 evolution with benzyl alcohol (BA) oxidation to benzaldehyde (BAD) reaction allows the full utilization of the energy of light-induced electron and hole to produce fuel and valuable chemicals, which has received widespread attention recently. Herein, Co(OH)2 nanosheet array-graphene(GR) composites cocatalyst can be successfully synthesized by simple precipitation method, and then CdS nanoparticles are in situ grown in hybrid cocatalyst to finally obtain CdS-Co(OH)2-GR ternary photocatalysts. Composting of dual-cocatalyst with CdS facilitates the migration of photoinduced charge carriers of CdS, affords abundant active sites and makes the growth of CdS nanoparticles more uniform and dispersed. As a result, the CdS-Co(OH)2-GR ternary composites have shown a glorious performance, showing the H2 generation velocity of 1173.53 µmol h−1 g−1, and the conversion rate of benzyl alcohol has reached 100 % within 2 h, which has surpassed other prepared samples and most of analogous photocatalyst systems. We are confident that this study can supply a useful reference for the synthesis of dual-cocatalyst-modified semiconductor composites, and promote the development of photocatalytic coupling reaction system, in which sacrifice agents are free and energies of light-induced electron and holes can be fully utilized.