Constructing built-in electric field in heterogeneous interface of V2O5/MnFePBA for efficient oxygen evolution reaction and urea oxidation reaction

Developing heterojunction electrocatalysts with built-in electric field (BIEF) as bifunctional electrocatalysts for oxygen evolution reaction (OER) and urea oxidation reaction (UOR) to achieve clean hydrogen production and urea-containing wastewater degradation remains a significant challenge. Herein, we have ingeniously coated V₂O₅ on the surface of MnFe Prussian blue analogue (MnFePBA) nanospheres forming a heterojunction (V₂O₅/MnFePBA) via a simple hydrothermal method, and meanwhile BIEF formed within a heterojunction, which was characterized by series of characterizations. Benefiting from the BIEF influence, the V₂O₅/MnFePBA electrocatalyst required merely 260 mV of overpotential to realized a high current density (100 mA cm⁻²) in an electrolyte of 1.0 M KOH. What's more important, at the same high current density, V₂O₅/MnFePBA also delivered a potential of 1.36 V vs. RHE in a mixed electrolyte composed by 1.0 M KOH and 0.5 M urea. DFT calculations further demonstrated that BIEF could effectively adjust the electronic structure, induce the movement of the d-band center, and optimize intermediate adsorption, thereby decreasing the energy barrier favorable for the rate-determining step, which could accelerated the OER/UOR kinetics rates, thus V₂O₅/MnFePBA as a bifunctional electrocatalyst realized an efficient catalysis for OER and UOR. This work offers a promising approach to construct heterojunction with BIEF for enhancing both OER and UOR performance to produce green hydrogen and address urea-containing wastewater.