Photocatalysis for sustainable energy and environmental protection in construction: A review on surface engineering and emerging synthesis

The sustained growth in global energy demand and escalating environmental crises resulting from fossil fuel consumption underscore the urgent need for sustainable technologies. Photocatalysis, which harnesses solar energy to drive redox reactions for concurrent clean fuel production and pollutant degradation, has demonstrated significant potential for diverse applications. However, conventional photocatalysts are hindered by intrinsic limitations such as restricted visible-light absorption, rapid electron–hole recombination, and insufficient structural stability. In addition, extrinsic challenges, including mass transfer constraints, catalyst deactivation, and the formation of toxic by-products, further impede practical implementation. Existing reviews typically address these issues in isolation or focus on single materials (e.g., TiO₂), thereby lacking a comprehensive, state-of-the-art perspective. To fill this gap, this review systematically summarizes and critically evaluates the key bottlenecks hindering the practical application of photocatalytic technologies. It provides an in-depth overview of advanced surface functionalization and interfacial engineering strategies designed to overcome these limitations, including ferroelectric polarization, hydrogel-supported composite structures, defect engineering, and heterojunction/homojunction systems, while thoroughly elucidating the synergistic effects among these strategies. Furthermore, the review highlights emerging low-carbon and scalable synthetic approaches such as green biosynthesis, microfluidics, plasma-assisted electrolysis, and mechanochemistry, by comparing their potential for industrial-scale production. Finally, it outlines future research directions, emphasizing the pivotal roles of machine learning, interdisciplinary integration, and scalable manufacturing in transitioning photocatalytic innovations from laboratory settings to industrial applications. Overall, this review offers a comprehensive analytical framework and strategic insights to facilitate the transformation of photocatalysis from laboratory research to practical industrial-scale implementation.