CoSe₂ Embedded in C₃N₄: An Efficient Photocathode for Photoelectrochemical Water Splitting

An efficient H₂ evolution catalyst is developed by grafting CoSe₂ nanorods into C₃N₄ nanosheets. The as-obtained C₃N₄-CoSe₂ heterostructure can show excellent performance in H₂ evolution with outstanding durability. To generate phatocathode for photoelectrochemical water splitting CoSe₂ grafted in C₃N₄ was decorated on the top of p-Si microwires (MWs). p-Si/C₃N₄-CoSe₂ heterostructure can work as an efficient photocathode material for solar H₂ production in PEC water splitting. In 0.5 M H₂SO₄, p-Si/C₃N₄-CoSe₂ can afford photocurrent density -4.89 mA/cm² at "0" V vs RHE and it can efficiently work for 3.5 h under visible light. Superior activity of C₃N₄-CoSe₂ compared to CoSe₂ toward H₂ evolution is explained with the help of impedance spectroscopy.