Enhanced Light Trapping and Charge Separation via Pyramidal Cu₂O/NiCo-LDH Photocathode for Efficient Water Splitting

Abstract

To improve PEC water splitting efficiency, Cu2O thin film electrodeposites on pyramidal Si (PSi) was innovatively introduced as an antireflective substrate combining with an Au layer. In this way, a PSi/Au/Cu2O photocathode exhibits a photocurrent enhanced 330% more than that of bare planar Si/Au/Cu2O photocathode. Compared with reversible hydrogen electrode the final fabricated photocathode with earth-abundant NiCo-LDH semiconductor cocatalyst exhibits a highly competitive photocurrent of 7.54 mA cm–2 at 0 V. It mainly results from the improved light trapping, enhanced carrier separation, and NiCo-LDH with triple enhanced effects. That means p-Cu2O and NiCo-LDH possess a type-II heterojunction to enhance photocarrier separation efficiency. Ultimately, NiCo-LDH semiconductor cocatalyst also acts as a maskant which can enhance PSi/Au/Cu2O photocathode stability. Through light trapping effect of the pyramidal Si structure and type-II heterojunction for efficient charge separation, this work provide insight into superior performance in PEC water splitting.