Construct Ni–SnO2 core coated amorphous Ni(BO2)2 shell boosts water splitting for hydrogen production

Through a simple redox reaction, the precursor of Ni (OH)2 mixed with SnO2 was in situ transformed into a core-shell structure with elemental Ni blend SnO2 as the core and nickel metaborate as the shell. The metaborate shell is an excellent adsorption site for water molecules, which paves the way for subsequent hydride adsorption. When a small amount of SnO2 is mixed with elemental Ni, the electronic structure is optimized, and the electron enrichment of Ni is realized, making the hydrogen adsorption performance better. This core-shell synergy promotes the Vomer step in HER, thereby enhancing HER performance. In addition, Ni–Sn@NiBO/NF possesses larger electrochemical surface area and smaller charge transfer resistance. Only an overpotential of 22 mV is needed to drive a current density of 10 mA cm−2, indicating the excellent HER performance of the Ni–Sn@NiBO/NF catalyst. At high current density of 50 mA cm−2, the overpotential is only 79 mV. When Ni–Sn@NiBO/NF is used as the bifunctional catalyst for coupling HER and OER, the voltage is only 1.595 V at 10 mA cm−2. It shows that the catalyst has great application potential in electrocatalytic water decomposition to produce hydrogen.