Targeted doping induces interfacial orientation for constructing surface-functionalized Schottky junctions to coordinate redox reactions in water electrolysis
Guangping Yang, Tianxiang Yang, Zhiguo Wang, Ke Wang, Mengmeng Zhang, Peter D. Lund, Sining Yun
Abstract
Tuning the surface properties of catalysts is an effective method for accelerating water electrolysis. Herein, we propose a directional doping and interfacial coupling strategy to design two surface-functionalized Schottky junction catalysts for coordinating the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Directional doping with B/S atoms endows amphiphilic g-C3N4 with significant n-/p-type semiconductor properties. Further coupling with Fe3C modulates the energy band levels of B–C3N4 and S–C3N4, thus resulting in functionalized Schottky junction catalysts with specific surface-adsorption properties. The space-charge region generated by the dual modulation induces a local “OH−- and H+-enriched” environment, thus selectively promoting the kinetic behavior of the OER/HER. Impressively, the designed B–C3N4@Fe3C||S–C3N4@Fe3C pair requires only a low voltage of 1.52 V to achieve efficient water electrolysis at 10 mA cm−2. This work highlights the potential of functionalized Schottky junction catalysts for coordinating redox reactions in water electrolysis, thereby resolving the trade-off between catalytic activity and stability.