CoGa-Layered double hydroxides modified tin-doped hematite photoanode for efficient solar water splitting

Hematite suffers from low carrier concentration, limited hole diffusion distance, intricate surface states, and sluggish kinetic process of water oxidation, resulting in its inadequate performance for photoelectrocatalytic (PEC) water oxidation. This paper presents a method that combines tin doping and in situ growth of cobalt-gallium layered hydroxide co-catalysts to enhance the performance of the α-Fe 2 O 3 photoanodic oxygen evolution reaction (OER). The optimal CoGa-LDH/Sn-Fe 2 O 3 exhibits a significantly improved photocurrent density of 1.08 mA/cm 2 at 1.23 V vs. RHE, representing an 86 % enhancement compared to that of Sn-Fe 2 O 3 , and it demonstrates remarkable stability. Additionally, the cathodic displacement of CoGa-LDH/Sn-Fe 2 O 3 is observed to be 80 mV relative to the onset potential of Sn-Fe 2 O 3 . Systematic studies have demonstrated that tin doping significantly enhances the density of carriers in hematite and reduces the charge migration impedance of hematite, while the utilization of CoGa-LDH co-catalysts mitigates the complexation of photogenerated electron-hole pairs and reduces the transport resistance of photogenerated holes at the photoanode-electrolyte interface, consequently promoting the mobility of holes.