Aluminum doped nickel-molybdenum oxide for both hydrogen and oxygen evolution reactions

The exploration of cost-efficient electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are imperative in the field of sustainable energy development process. In this work, NiMoO4 with different doping levels of aluminum stoichiometry are synthesized (named as Al-NiMoO4-rods, Al-NiMoO4-sheets) by a simple one-step hydrothermal method. Doping of aluminum leads to the changes of structure for material, which increases the number of active sites and conductivity, and more gas channels are beneficial to facilitate the release of gas to achieve the purpose of improving electrochemical performance. Benefiting from the good electrochemical conductivity and structural stability, the Al-NiMoO4-rods can achieve good performance of HER activity, with an overpotential of 131 mV at the current density of 10 mA cm−2 and OER activity with an overpotential of 259 mV at the current density of 50 mA cm−2 and small Tafel slopes of 82 mV dec−1 and 117 mV dec−1, respectively, outperforming the comparative samples. The results of this investigation show that Al play an important role in determining the structure and electrochemical properties of Al-NiMoO4-rods, which can serve as an efficient and bifunctional electrocatalyst.