Exploring critical development in photocatalytic overall water splitting: Recent trend, races predictions and environmental impacts

Despite intensive research on solar-driven photocatalytic overall water splitting (POWS), the overall efficiencies remain insufficient to meet commercial standards. As a central challenge in realizing this technology mainly lies in the precise tuning and rational designing of highly efficient materials and photocatalytic systems, which is paramount for its unlocking scalable, practical applications. However, novel materials fabrication and advanced photocatalytic systems are essential for overcoming intrinsic limitations of conventional catalysts by enabling this green technology to resolve global energy crisis. Therefore, this review critically explores the engineering developments in POWS process and novel photocatalyst designing, via shifting from simple bandgap engineering to more advanced charge carrier dynamics control via utilizing one/two-step photocatalytic excitation system, surface phase junctions i.e., Z-scheme and S-scheme heterojunctions, surface modification, morphological tuning, and the role of co-catalysts, to control sluggish kinetics, promote oxygen evolution reaction (OER) and suppress undesirable H 2 /O 2 , backward reaction with superior visible light absorption capacity to produce remarkable energy production. Moreover, we critically discuss the recent trend of POWS from a materials discovery phase to demanding engineering and mechanistic optimization phase with viable economic viability, which requires bridging the gap between excellent lab-scale performance to stringent stability, cost, and high efficiency demands of industrial-scale solar fuel production. In addition, the currents challenges and future directions are also enclosed in detail for sustainable energy production.