Metal-Organic Framework Derived Ni2P/FeP@NPC Heterojunction as Stability Bifunctional Electrocatalysts for Large Current Density Water Splitting

The construction of heterojunction has been widely accepted as a prospective strategy for the exploration of non-precious metal-based catalysts that possess high-performance to achieve electrochemical water splitting. Herein, we design and prepare a metal-organic framework derived N, P-doped-carbon-encapsulated Ni2P/FeP nanorod with heterojunction (Ni2P/FeP@NPC) for accelerating the water splitting and working stably at industrially relevant high current densities. Electrochemical results confirmed that Ni2P/FeP@NPC could both accelerate the hydrogen and oxygen evolution reactions. It could substantially expedite the overall water splitting (1.94 V for 100 mA cm(-2)) which is close to the performance of RuO2 and the Pt/C couple (1.92 V for 100 mA cm(-2)). In particular, the durability test exhibited that Ni2P/FeP@NPC delivers 500 mA cm(-2) without decay after 200 h, demonstrating the great potential for large-scale applications. Furthermore, the density functional theory simulations demonstrated that the heterojunction interface could give rise to the redistribution of electrons, which could not only optimize the adsorption energy of H-containing intermediates to achieve the optimal Delta G(H)* in a hydrogen evolution reaction, but also reduce the Delta G value in the rate-determining step of an oxygen evolution reaction, thus improving the HER/OER performance.

Automated summary

The construction of heterojunction is a promising approach for developing high-performance non-precious metal-based catalysts for electrochemical water splitting. In this study, a metal-organic framework derived N, P-doped-carbon-encapsulated Ni2P/FeP nanorod with heterojunction was designed and prepared. The results showed that the Ni2P/FeP@NPC catalyst exhibited efficient hydrogen and oxygen evolution reactions, and achieved overall water splitting at industrially relevant high current densities.