Linker-assisted composite of MoS2 and g-C3N5: sunlight-driven efficient photocatalytic hydrogen production

Abstract

A photocatalyst capable of harnessing direct sunlight for producing hydrogen through water splitting is the need of the hour. In this work, this is achieved by depositing hydrothermally prepared MoS₂ over APTES-modified, nitrogen-rich graphitic carbon nitride (g-C₃N₅) to form a heterostructure. This heterojunction composite demonstrates elevated rates of hydrogen evolution via a triethylamine-assisted photocatalytic reaction, as evidenced by both photoelectrochemical and photocatalytic performances. The optimized sample of 5% MoS₂/g-C₃N₅ composite accomplished photocatalytic hydrogen production of 1184.4 µmol g⁻¹ h⁻¹ under a solar simulator and 3184 µmol g⁻¹ h⁻¹ when exposed to direct sunlight. A high cathodic current density (−321 µA cm⁻² for 5% MoS₂/g-C₃N₅, at 0.0 V vs. RHE) in linear sweep voltammetry (LSV) and an immediate current response in a transient current study during photoelectrochemical hydrogen evolution reactions (PEC HER) validate its high efficacy for hydrogen evolution. A significant increase in light absorption, charge separation, and charge carrier migration in the composite accounts for the enhancement in photoactivity. The study provides a roadmap for the construction of stable g-C₃N₅ composites with transition metal chalcogenides for green hydrogen production.