Improved Photocatalytic Hydrogen Evolution of CdS Using Earth-Abundant Cocatalyst Mo2N with Rod Shape and Large Capacitance

Earth-abundant catalysts (cocatalysts) for photocatalysis, photoelectrocatalysis, and electrocatalysis have attracted increased attention due to the potentially reduced cost for large-scale application. Here, we first report and demonstrate that improving the capacitance of cocatalysts of Mo2N by modifying the morphology and orientations could produce a better photocatalytic hydrogen evolution reaction (HER) activity on CdS. Among rod, sheet, and sphere shapes of Mo2N, the (111)-orientated rod h-Mo2N was found to be the most efficient. The hydrogen evolution activity of h-Mo2N/CdS is 6.1 times that of the Pt/CdS and 30.1 times that of the bare CdS. A controlling experiment showed that the superior photocatalytic HER activity can be attributed to the higher capacitance of h-Mo2N. This study opens up a pathway to develop novel cocatalysts for photocatalyst by adjusting the capacitance through morphology controls.