High Efficiency Photocatalytic Water Splitting Using 2D α‐Fe2O3/g‐C3N4 Z‐Scheme Catalysts

Photocatalysis is the most promising method for achieving artificial photosynthesis, but a bottleneck is encountered in finding materials that could efficiently promote the water splitting reaction. The nontoxicity, low cost, and versatility of photocatalysts make them especially attractive for this application. This study demonstrates that small amounts of α‐Fe2O3 nanosheets can actively promote exfoliation of g‐C3N4, producing 2D hybrid that exhibits tight interfaces and an all‐solid‐state Z‐scheme junction. These nanostructured hybrids present a high H2 evolution rate >3 × 104 µmol g‐1 h‐1 and external quantum efficiency of 44.35% at λ = 420 nm, the highest value so far reported among the family of g‐C3N4 photocatalysts. Besides effectively suppressing the recombination of electron–hole pairs, this Z‐scheme junction also exhibits activity toward overall water splitting without any sacrificial donor. The proposed synthetic route for controlled production of 2D g‐C3N4‐based structures provides a scalable alternative toward the development of highly efficient and active photocatalysts. A Z‐scheme catalyst is considered as a promising material for photocatalytic water splitting. α‐Fe2O3 can actively promote exfoliation of g‐C3N4, producing two‐dimensional Z‐scheme α‐Fe2O3/2D g‐C3N4. Hybrids show a high H2 evolution rate of 31 400 μmol g−1 h−1 and significantly enhanced quantum efficiency up to 44.35% (λ = 420 nm), which is the highest value so far reported for g‐C3N4‐based photocatalysts.