Hydrogen generation promoted by photocatalytic oxidation of ascorbate and glucose at a cadmium sulfide electrode

摘要

Photocatalytic oxidation of ascorbate (AA) and glucose (GLU) on a visible light-sensitive cadmium sulfide nanoparticle modified indium-tin oxide (CdS/ITO) electrode has been successfully used to synergistically promote the photoelectrochemical generation of hydrogen on a porous nickel cathode. In a neutral medium, the photocatalytic oxidation of AA is found to drive the oxidation of GLU on the visible light-excited CdS/ITO anode, which yields the photovoltaic effect to improve the hydrogen evolution reactions. The optimized monopolar photocatalytic fuel cell using 0.1 mol L-1 AA and 0.1 mol L-1 GLU as fuel shows open-circuit photovoltage of 0.571 V (vs. SCE) upon visible light irradiation of 0.18 mW cm(-2), short-circuit photocurrent density of 166.67 mu A cm(-2), maximum power density of 23.34 mu W cm(-2) at 0.275 V. The simultaneous presence of AA and GLU leads to a 22.1-fold increase of photoenergy conversion efficiency in contrast to that without fuel. Furthermore, the photocatalytic responses of the CdS/ITO electrode towards the oxidation of AA and GLU are found to remarkably promote the photoelectrochemical generation of hydrogen, which is evaluated with solar-to-hydrogen and fuel-to-hydrogen conversion efficiencies. This present study provides a new approach for better utilizing renewable energy sources to promote the hydrogen generation. (C) 2016 Published by Elsevier Ltd.