Dual strategy of ultrasound and doping enhance Mott Schottky heterojunction carrier exchange for efficient oxygen evolution

Metal–organic frameworks (MOFs) materials are highly efficient materials for catalytic hydrogen production from electrolytic water, but the electronic configuration severely limits catalytic activity. In this study, UE-S-FeBTC was synthesized on metal substrate nickel iron foam (NIF) by one-step electrodeposition to construct Mott Schottky heterojunction. Chemical S doping mixes the p-π conjugation in the overall d-π conjugation system, effectively modulating the electronic configuration of FeBTC and enhancing carrier diffusion at the interface. Moreover, physical ultrasound of the synthesis process results in a tighter contact interface, thus improving the carrier exchange between the semiconductor and the substrate, which causes a further enhancement of flat band potential (FBP). The material exhibits good catalytic activity, requiring only 306 mV overpotential to drive 100 mA cm−2 and remains stable at 200 mA cm−2 for up to 12 h. Excellent catalytic activity derived from closer contact at the Mott Schottky heterojunction interface and the larger specific surface area formed by sonication resulting in the loading of more active sites. The stronger FBP also effectively improves the carrier density at the catalytic active site. This study provides a new design idea for the construction of Mott Schottky heterojunction catalysts with strong FBP.