Emerging frontiers of Z-scheme photocatalytic systems

Solar-driven fuel production is considered a promising strategy to solve the growing global energy demands and environmental problems. Z-scheme heterojunctions have been reported to exhibit considerably improved photocatalytic fuel production due to enhanced light harvesting, spatially separated reductive and oxidative active sites, and strong redox capability. Understanding the fundamental principles of Z-scheme photocatalytic systems and mastering their improvement strategies will help greatly with the further development of highly efficient Z-scheme photocatalysts for solar-driven fuel production and other photocatalytic applications. Z-scheme photocatalysts have recently received tremendous attention because of their strong light utilization and redox ability. This cutting-edge photocatalytic platform allows photocatalysts to convert light into chemical energy with high activity, selectivity, and stability. In this review, we highlight some of the recent key contributions in the field, including fundamental principles, advanced characterization methods, and a series of photocatalytic applications (e.g., water splitting, CO2 reduction, N2 fixation, H2O2 production). Significant improvement strategies for Z-scheme photocatalysts are also discussed and summarized. With increasing achievements, Z-scheme photocatalytic systems (PSs) will make a historic breakthrough in activity, solar utilization, selectivity, and fabrication cost and move toward practical production in the near future. Z-scheme photocatalysts have recently received tremendous attention because of their strong light utilization and redox ability. This cutting-edge photocatalytic platform allows photocatalysts to convert light into chemical energy with high activity, selectivity, and stability. In this review, we highlight some of the recent key contributions in the field, including fundamental principles, advanced characterization methods, and a series of photocatalytic applications (e.g., water splitting, CO2 reduction, N2 fixation, H2O2 production). Significant improvement strategies for Z-scheme photocatalysts are also discussed and summarized. With increasing achievements, Z-scheme photocatalytic systems (PSs) will make a historic breakthrough in activity, solar utilization, selectivity, and fabrication cost and move toward practical production in the near future. a typical layered 2D material with puckered layers of phosphorus stacked together via van der Waals forces. the energy band formed by free electrons. a unique class of materials that combine extended π-conjugation with a permanently microporous skeleton. one of the most widely used theoretical calculation technologies. a Z-scheme photocatalyst that shows photocatalytic activity under all wavelengths of light. an emerging 2D layered transition-metal carbide/carbonitride/nitride. metal–semiconductor contact that has a negligible contact resistance relative to the bulk or series resistance of the semiconductor. the charge-transfer route in S-scheme mode resembles a macroscopic ‘step’ (from low CB to high VB; Figure 1D). MoS2 with unsaturated S atoms on exposed edges as reactive sites forms three stacked atomic layers. the energy band formed by valence electrons. the minimum energy required to move an electron from the interior of a solid to its surface. the photogenerated carrier transfer route looks like the letter Z.