Amorphous NiWO4 nanoparticles boosting the alkaline hydrogen evolution performance of Ni3S2 electrocatalysts

Heazlewoodite nickel sulfide (Ni 3 S 2 ) has become attractive for electrocatalytic hydrogen evolution reaction (HER). However, strong sulfur–hydrogen bonds (S–H ads ) formed on the surface of Ni 3 S 2 greatly hinder the H ads desorption and reduce HER activity. Herein, amorphous NiWO 4 nanoparticles-decorated Ni 3 S 2 electrocatalysts (NiWO 4 /Ni 3 S 2 ) have been constructed via a two-step hydrothermal method. The heterostructures exhibit much better HER performance than original Ni 3 S 2 by delivering current densities of −10 and −100 mA cm −2 at low overpotentials of 136 and 274 mV, while those for Ni 3 S 2 are 234 and 424 mV, respectively. Moreover, they display ultra-long stability of 75 h. Theoretical calculation proves the improved activity of NiWO 4 /Ni 3 S 2 heterostructures is attributed to highly active interfaces between amorphous NiWO 4 nanoparticles and Ni 3 S 2 electrocatalysts. The strong electronic interaction between NiWO 4 and Ni 3 S 2 decreases the local electron density of Ni and S atoms, facilitates water adsorption on Ni-sites and optimizes hydrogen atom adsorption/desorption on adjacent S-sites with weakened S–H ads .