In-situ engineered heterostructured nickel tellur-selenide nanosheets for robust overall water splitting

Due to the large Gibbs free energy of metal telluride for hydrogen generation, tellurium (Te) based materials are rarely reported as catalysts for overall water splitting. Herein, a facile hydrothermal method is used to engineer the stacked flower-like NiTe-NiSe nanosheets, thus nearing the application of transition metal telluride in clean and renewable energy field. Thanks to the hollow flower-shaped catalyst assembled with nanosheets, the active surface area of the optimized electrode material is 20 times larger than that of a single NiTe/NFF or NiSe/NFF, causing low overpotentials for delivering a current density of 10 mA cm-2 (j10) in the hydrogen (HER, 76 mV) and oxygen (OER, 164 mV) evolution processes. The OER activity of NiTe-NiSe/NFF exceeds that of benchmarked RuO2 even at moderate current densities above j115. Based on the results of experiments and DFT calculations, the unexpected high catalytic performance of NiTe-NiSe/NFF is attributed to the formed heterointerfaces and mismatched crystal lattice of NiTe, which effectively optimize the electronic structure through the phase synergy and cause a low adsorption free energy for the reactive intermediates.