Simultaneous theoretical hydrogen generation and COD removal from refinery wastewater using rutile TiO ₂ /α‐ Fe ₂ O ₃ photoanodes in a laser‐assisted photoelectrochemical system

Water pollution and increasing energy demand require sustainable technologies capable of integrating environmental remediation with resource recovery. In this study, a laser‐assisted photoelectrochemical (PEC) system employing rutile TiO 2 /α‐Fe 2 O 3 photoanodes was investigated for simultaneous chemical oxygen demand (COD) removal from real refinery wastewater and theoretical hydrogen generation estimation. The photoanodes were irradiated using combined ultraviolet and visible laser wavelengths (473, 532, and 632 nm) at a total light intensity of 100 mW cm −2 . Under the optimum operating conditions (pH 3, 40°C, 50 min, and 0.4 mg cm −2 ), the system achieved 96.78% COD removal with a theoretically estimated hydrogen yield of 8042 μmol L −1 . Enhanced performance resulted from improved charge separation and interfacial electron transfer within the TiO 2 /α‐Fe 2 O 3 heterojunction under multi‐wavelength excitation, demonstrating an effective strategy for sustainable wastewater treatment and theoretical hydrogen recovery.