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.