Surface states regulation of sulfide-based photoanode for photoelectrochemical water splitting

Regulating the surface states distribution on the photoanode/electrolyte interface is crucial to photoelectrochemical (PEC) water splitting. Here we develop a CdIn2S4/InOx/NiFe-LDH adaptive junction to improve the PEC performance and stability of bare CdIn2S4, which achieves a photocurrent density of 5.47 mA cm−2 at 1.23 VRHE as well as good durability under AM 1.5G illumination without sacrificial reagent. The experimental characterizations evidence that both the charge carrier density (Nd) and surface states distribution (Nss) alter along with the interfacial structural regulation in the CdIn2S4/InOx/NiFe-LDH photoanode, and a proper ratio of Nss/Nd guarantee the optimal photocurrent. Meanwhile, a strained surface states distribution and negative shifted Nss center facilitate the charge transfer and interfacial water oxidation kinetics as well. This work highlights the influence of interfacial structural regulation on the entangled surface states distribution and charge carrier density and may inspire more excellent work on designing other efficient photoanodes.