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

This study employed silicon@cobalt dichalcogenide microwires (MWs) as wide range pH-tolerable photocathode material for solar water splitting. Silicon microwire arrays were fabricated through lithography and dry etching technologies. Si@Co(OH)2 MWs were utilized as precursors to synthesize Si@CoX2 (X = S or Se) photocathodes. Si@CoS2 and Si@CoSe2 MWs were subsequently prepared by thermal sulfidation and hydrothermal selenization reaction of Si@Co(OH)2, respectively. The CoX2 outer shell served as cocatalyst to accelerate the kinetics of photogenerated electrons from the underlying Si MWs and reduce the recombination. Moreover, the CoX2 layer completely deposited on the Si surface functioned as a passivation layer by decreasing the oxide formation on Si MWs during solar hydrogen evolution. Si@CoS2 photocathode showed a photocurrent density of -3.22 mA cm(-2) at 0 V (vs RHE) in 0.5 M sulfuric acid electrolyte, and Si@CoSe2 MWs revealed moderate photocurrent density of -2.55 mA cm(-2). However, Si@CoSe2 presented high charge transfer efficiency in neutral and alkaline electrolytes. Continuous chronoamperometry in acid, neutral, and alkaline solutions was conducted at 0 V (vs RHE) to evaluate the photoelectrochemical durability of Si@CoX2 MWs. Si@CoS2 electrode showed no photoresponse after the chronoamperometry test because it was etched through the electrolyte. By contrast, the photocurrent density of Si@CoSe2 MWs gradually increased to -5 mA cm(-2) after chronoamperometry characterization owing to the amorphous structure generation.

CoTe2@TiO2-Si-MWs provide active sites for proton reduction and combine surface hydrogen atoms into molecular hydrogen.

A plasmonic photoelectrochemical system was constructed by alternating the conventional Pt electrode for utilizing a wide range of the solar spectrum.