Mixed Metal Oxides as Solar-Driven Multi-Functional Materials for Water, Air, and Carbon Remediation: A Theoretical Perspective

Mixed transition metal oxides (MTMOs) are emerging as promising multifunctional materials that couple solar energy conversion with environmental remediation. Their tunable band structure, redox flexibility, and oxygen vacancy–mediated reactivity enable simultaneous photocatalytic degradation of organic pollutants, oxidation of gaseous contaminants, and reduction of CO₂ into value-added fuels. This paper presents a theoretical framework for understanding the multi-functionality of MTMOs through the lens of electronic structure, defect chemistry, and surface energetics. Density Functional Theory (DFT) insights reveal how cation synergy and oxygen vacancy formation energies dictate charge transfer efficiency and adsorption selectivity. Finally, a holistic design roadmap is proposed—linking atomic-scale descriptors to macroscopic environmental performance—paving the way for solar-driven, self-regenerating oxide systems for sustainable water, air, and carbon remediation