Graphdiyne-engineered heterostructures for efficient overall water-splitting

Abstract Efficient overall water splitting (OWS) into hydrogen and oxygen needs an electrocatalyst that can effectively catalyze hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the same electrolyte. Here a new electrocatalyst of graphdiyne-coated nickel oxide heterostructures is synthesized. It can effectively facilitate the charge transfer, increase the electrocatalytically active surface area, maximize the number of electrocatalytically active sites, and protect the catalyst from corrosion during the stability test. Benefiting from these advantages, the electrocatalyst shows superior HER and OER catalytic activities than commercial Pt/C and RuO 2 , respectively. When being used as both cathode and anode in a two-electrode alkaline electrolyzer, the graphdiyne-based heterostructure shows an excellent OWS performance superior to that of the Pt/C||RuO 2 couple. In combination with the theoretical calculations, our results reveal that the as-synthesized heterostructure can significantly improve the charge transfer kinetics and the hydrogen/oxygen-containing species adsorption abilities, therefore maximizing the overall water splitting activities.