Earth‐Abundant Tin Sulfide‐Based Photocathodes for Solar Hydrogen Production

Tin‐based chalcogenide semiconductors, though attractive materials for photovoltaics, have to date exhibited poor performance and stability for photoelectrochemical applications. Here, a novel strategy is reported to improve performance and stability of tin monosulfide (SnS) nanoplatelet thin films for H(2) production in acidic media without any use of sacrificial reagent. P‐type SnS nanoplatelet films are coated with the n‐CdS buffer layer and the TiO(2) passivation layer to form type II heterojunction photocathodes. These photocathodes with subsequent deposition of Pt nanoparticles generate a photovoltage of 300 mV and a photocurrent density of 2.4 mA cm(−2) at 0 V versus reversible hydrogen electrode (RHE) for water splitting under simulated visible‐light illumination (λ > 500 nm, P (in) = 80 mW cm(−2)). The incident photon‐to‐current efficiency at 0 V versus RHE for H(2) production reach a maximum of 12.7% at 575 nm with internal quantum efficiency of 13.8%. The faradaic efficiency for hydrogen evolution remains close to unity after 6000 s of illumination, confirming the robustness of the heterojunction for solar H(2) production.