Photoelectrocatalytic hydrogen evolution combined with organic waste water treatment by red mud derived catalysts

Photoelectrocatalytic (PEC) water splitting is a green technology for hydrogen generation using solar energy. When coupled with wastewater as the water source, this approach simultaneously addresses environmental remediation. This study proposes a sustainable strategy for producing green hydrogen from organic wastewater, where H₂ evolution occurs concurrently with pollutant degradation. To reduce catalyst costs, we fabricated FeOOH/BiVO₄ composite photoanodes using red mud as a raw material. The degradation performance of these photoanodes was systematically investigated under varying voltages, pH levels, and initial pollutant concentrations. Comparative analysis of PEC, photocatalytic, and electrocatalytic pathways revealed the superior efficiency of PEC under identical conditions. Under optimized parameters, the composite photoanode achieved ∼98 % degradation of methylene blue (40 mg/L) within 120 min, along with effective removal of other organic pollutants (methyl orange, rhodamine B, and reactive red). Hydrogen evolution experiments confirmed the synergistic coexistence of PEC degradation and water splitting in a single system. By converting solid waste into efficient catalysts for simultaneous hydrogen production and pollutant degradation, this work offers a multifunctional green solution to energy and environmental challenges.