Engineered cellulose-supported photocatalysts for clean energy and environmental remediation: progress and prospects

Abstract

The growing global demand for sustainable energy and environmental remediation has accelerated interest in efficient, metal-free photocatalysts. Cellulose, known for its abundance, biodegradability, tunable chemistry, high surface area, and mechanical robustness, has emerged as an ideal support material for photocatalytic systems. This review presents a comprehensive evaluation of cellulose-supported photocatalysts, detailing their structural forms, physicochemical properties, preparation strategies, and design principles. The classification of cellulose-based composites and structured architectures into hydrogels, aerogels, membranes, and sponges highlights the versatility of cellulose in enhancing catalyst dispersion, charge separation, visible-light activity, and reusability. Their applications include hydrogen and hydrogen peroxide generation, nitrogen fixation, CO₂ reduction and wastewater treatment and disinfection. Strengths, weaknesses, opportunities, and threats (SWOT) analysis provides insights into their strengths, limitations, and research gaps, emphasizing challenges in large-scale fabrication, stability, and commercial viability. Furthermore, this review highlights the significance of environmental and economic analyses to guide their sustainable scale-up and market adoption. Future directions should focus on heterostructure engineering, defect modulation, green synthesis, AI-guided optimization, and integration into real-world systems. By bridging materials science, catalysis, and environmental engineering, cellulose-supported photocatalysts hold significant potential for scalable, eco-friendly, and multifunctional solutions aligned with the fundamentals of circular economy, green chemistry, and the United Nations Sustainable Development Goals.