Electron density regulation of bimetal phosphates via heterojunction interface engineering for electrocatalytic reaction

Construction of heterojunction inside a catalyst can induce electron redistribution with optimization of adsorption and desorption with [H] and [O] intermediates, attributed to accelerate HER and ORR process. In this work, we designed novel catalysts for HER and ORR by structuring a coralloidal morphology and controlling the synthetic process. The polyphosphazene framework was built via hexachlorocyclotriphosphazene (HCCP) polymerization, which was used as the metal-organic framework (MOF) particle supporter. The polyphosphazene framework was beneficial for the growth of MOF particles with a coralloidal morphology, which exposed catalytic active sites. The polyphosphazene framework provides an abundance heteroatom of nitrogen and phosphorus that modulate the electron density of the metal for catalytic process. The coralloidal catalysts exhibited a versatile catalytic behavior for HER. In 0.1 M KOH, the ORR half-wave potential (HWP)of CoP@PNC (0.85 V) was higher to Pt/C (0.82 V). In 1.0 M KOH, MoP/CoMoP-1 @PNC had a good HER catalytic performance, and the overpotential at 10 mA cm-2 was 82 mV. DFT calculations demonstrate that multimetal phosphides can provide a heterojunction interface, thereby regulating the electron density for the catalytic reaction. This work provides a novel route to prepare high-efficiency catalysts by conjointly structuring the micromor-phology and heterojunction interface.