Three-dimensional multi-channel structure NiCo alloy used for boosting efficient overall water splitting

The development of high activity and low cost electrocatalysts for enhancing hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the focus of overall water splitting. It has been found that transition metals have the potential to be highly efficient catalysts. In this paper, NiCo alloy electrode and three-dimensional multi-channel NiCo alloy (3D NiCo alloy) electrode were prepared by chemical coprecipitation-thermal reduction method and impregnation method respectively, which were used for efficient overall water splitting. By adjusting the pH value, alloy electrodes with different morphologies were obtained. The 3D multi-channel structure improved the catalytic activity of the NiCo alloy electrode for HER and OER. In 0.5 M H2SO4, the 3D NiCo3 alloy electrode shows excellent catalytic activity for HER and OER. The HER overpotential of the 3D NiCo3 alloy electrode is 109.6 mV at the current density of −10 mA cm−2, while the corresponding Tafel is 81.23 mV dec−1. The overpotential is as low as 296 mV when the OER current density is 40 mA cm−2, and the corresponding Tafel is 32.58 mV dec−1. This is due to the large specific surface area of the 3D NiCo3 alloy electrode, and the synergistic effect between Ni-Co alloys and more active sites exposed by the three-dimensional multi-channel structure. It is shown that the morphology and structure have a great influence on the catalytic performance, and the transition metal electrocatalyst has a bright industrial application prospect.