The synergistic effect of Co/CoO hybrid structure combined with biomass materials promotes photocatalytic hydrogen evolution

Developing photocatalysts with high efficiency and low cost for water splitting is significant in the production of hydrogen using solar energy. In this report, a low-cost and environmentally-friendly photocatalyst (Co-CN-500) is achieved through a simple calcination procedure with natural chitin and cobalt nitrate as raw materials. With Eosin Y as photosensitizer in triethanolamine (TEOA) solution, the hydrogen evolution rate of Co-CN-500 can reach 12.63 mmol g-1 h-1, which is higher than that of commercial Pt-C (10.34 mmol g-1 h-1) and other reported cobalt-containing photocatalysts. Characterization results prove the hybrid structure of cobalt ingredients involving cobalt monoxide and metal cobalt is essential for excellent photocatalytic performance. DFT calculations confirm the free energy of hydrogen adsorption and work function on Co/CoO hybrid surface are smaller than on Co (111) and CoO (111), making it easier to form adsorbed H that then produce H2.