Metal-Organic Framework Templated Synthesis ofg-C3N4/Fe2O3@FeP Composites for Enhanced Hydrogen Production

The simultaneous construction of heterostructures and co-catalyst loading while maintaining a tight contact favoring charge transfer is important for improving the photocatalytic H-2 production of g-C3N4. Following this approach, we prepared herein a Fe2O3@FeP hybrid material by annealing and phosphidation of a g-C3N4/Fe metal-organic framework (MOF). The as-prepared Fe2O3@FeP was used as both heterojunction and co-catalyst material to enhance the photocatalytic H-2 evolution performance of g-C3N4 by water splitting under visible-light irradiation. We developed an optimized g-C3N4/Fe2O3@FeP-60 catalyst with a H-2 evolution rate as high as 12.03 mmol g(-1) h(-1) under Eosin Y (EY, 1.0 mmol L-1)-sensitization. This rate was 12 times higher than that of pristine EY-sensitized g-C3N4 (0.97 mmol g(-1) h(-1)). The apparent quantum efficiency (AQE) at 420 nm was 38.8 %. The improved photocatalytic activity of this composite compared to g-C3N4 can be ascribed to: (i) its enhanced visible-light absorption intensity; (ii) its efficient electron-hole separation by the formation of a type-II heterojunction with Fe2O3 and the loading of an electron collector such as FeP; and (iii) the accelerated H+ reductive reaction resulting from the FeP co-catalyst. We believe that this work may pave the way for the construction of MOF-based hybrid H-2-evolution photocatalysts.