Heterointerface of nickel-ferric hydroxide / cobalt-phosphide-boride boosting hydrazine-assisted water electrolysis

Sustainable H 2 production based on hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR) has attracted wide attention due to minimal energy consumption compared to overall water electrolysis. The present study focuses on the design and construction of heterostructured CoPB@NiFe–OH applied as efficient bifunctional catalysts to sustainably produce hydrogen and remove hydrazine in alkaline media. Impressively, CoPB@NiFe–OH heterointerface exhibits an HzOR potential of −135 mV at the current density of 10 mA cm −2 when the P to B atom ratio was 0.2, simultaneously an HER potential of −32 mV toward HER when the atom ratio of P and B was 0.5. Thus, hydrogen production without an outer voltage accompanied by a small current density output of 25 mA cm −2 is achieved, surpassing most reported catalysts. In addition, DFT calculations demonstrate the Co sites in CoPB upgrades H∗ adsorption, while the Ni sites in NiFe–OH optimizes the adsorption energy of N 2 H 4 ∗ due to electron transfer from CoPB to NiFe–OH at the heterointerface, ultimately leading to exceptional performance in hydrazine-assistant water electrolysis via HER coupled with HzOR. A robust bifunctional CoPB@NiFe–OH catalyst has been designed and constructed based on interfacial coupling effect. Benefitting from the efficient formed heterointerface, hydrogen-electric cogeneration can be spontaneously achieved via HzOR coupled with HER in hydrazine assisted water electrolysis system. • A heterointerface nanostructured catalysts composed by NiFe hydroxides nanosheets and amorphous CoPB (CoPB@NiFe–OH/NF) was successfully constructed by a facile hydrothermal coupled with electrodeposition method. • This CoPB@NiFe–OH/NF exhibited remarkable bifuctional electrocatalytic capacity toward HzOR and HER derived from the formed heterointerface, thus accelerating hydrazine-assisted water electrolysis. • DFT calculations demonstrate the Co sites in CoPB upgraded H∗ adsorption, while the Ni sites in NiFe–OH optimized the adsorption energy of N 2 H 4 ∗ due to electron transfer from CoPB to NiFe–OH at the heterointerface.