Charge Dynamic Interface Z‐Scheme on r‐GO–WO ₃ –α‐Fe ₂ O ₃ Composite Surface for Hydrogen Production

Abstract N‐type thin films of semiconductors WO 3 , α‐Fe 2 O 3 , and nanocomposite structures of WO 3 –α‐Fe 2 O 3 , and WO 3 –α‐ Fe 2 O 3 –r‐GO were prepared on FTO substrates using spray deposition. The optical, morphological, structural, crystallinity, and composition properties were studied by UV–visible spectroscopy, SEM, TEM, XRD, and EDS. Photoelectrochemical efficiency was assessed in a three‐electrode cell assembly and validated through various electrochemical measurements. The improved light absorption capacity of WO 3 –α‐Fe 2 O 3 –r‐GO composites is due to synergistic effect and hierarchical nanostructures with ultrahigh surface areas enhanced by the incorporation of r‐GO. The reduction potentials of WO 3 and Fe 2 O 3 can be tuned by controlling morphology and particle size. WO 3 as a photoanode suffers from volumetric and structural changes during redox reactions, leading to instability and decreased photocurrent response. Hematite is a promising candidate for PEC water splitting due to its lower bandgap (2.0–2.2 eV) and excellent electrochemical stability in electrolytes. However, it has drawbacks such as low quantum efficiency and short hole diffusion length. The combined benefits of r‐GO, hematite, and WO 3 in WO 3 –α‐Fe 2 O 3 –r‐GO composite effectively detect electron dynamics across WO 3 –α‐Fe 2 O 3 interface with r‐GO serving as a mediator to study charge dynamics at interface. The critical role of r‐GO in enhancing electrochemical performance of nanocomposites has been well established.