Preparation Of Metal Sulfide Composite Photocatalyst And Its Mechanism In Photocatalytic Hydrogen Production

Solar energy utilization technology has been extensively explored in solving the global energy crisis.As a sustainable solar energy,it has inexhaustible energy that can be fully converted into chemical fuels and electricity.Various semiconductors that are vital to the utilization of solar energy have been extensively developed.Among them,metal sulfides have received extensive attention due to their suitable band gap and excellent photoelectric properties.However,metal sulfides are still limited by rapid charge recombination,instability,and low quantum efficiency.A suitable band gap provides a huge opportunity for it to overcome the remaining challenges.This article focuses on the construction,preparation and mechanism of metal sulfide（Cd S,Ni S）nanocomposite photocatalysts in solar hydrolysis and hydrogen production.In this paper,a Cd S/Ti³⁺@N-TiO₂（TNTC）photocatalytic system was first prepared.Among them,N doping and Ti³⁺/OVs can effectively shorten the band gap value of TiO₂,thereby expanding the visible light absorption range.In addition,Ti³⁺ can also form a hydrogenation shell at the interface of TiO₂,thereby reducing the activation barrier of H₂ and promoting the reduction of H⁺to H₂.Cd S and TNT heterojunctions can form an internal electric field to generate carrier driving force,which can effectively promote the spatial separation of photo-generated carriers and enhance the production of photocatalytic hydrogen.Subsequently,a NiS/P@g-C₃N₄（NPCN）composite photocatalyst was prepared.The possible mechanism is to expand its light absorption edge through P element doping.The interaction force between the SP bonds produced by NiS/P@g-C₃N₄ is that the carriers quickly migrate to the active sites exposed on the surface to accumulate,and The rapid reaction of the promoter Ni S with water or H⁺generates H₂,which enhances the photocatalytic activity of the composite photocatalysis.The prepared TNTC and NPCN photocatalysts have good photocatalytic activity and stability in continuous photocatalytic experiments.