Ruijing Wang,Qunlong Wang,De Zhang,Qi Zhang,Lijuan Jiang,Youxia Liu,Qiang Wang,Xuefeng Wang
The electrolysis of water splitting is a critical technology to produce the hydrogen by green electricity. The design of highly efficient, low-cost, and stable electrocatalysts is the important point in this process. The structure modification by doping is concerned intensively because it optimizes the electronic conductivity and the absorption of reaction intermediates. The transition metal oxides are the efficient catalysts for water splitting under the alkaline electrolyte. However, the limited structure and number of surficial sites restrict the electrochemical activity. In this work, the phosphorus-doped CoMoO 4- x nanosheets on CoO nanowire (CoMoO 4-x P x /CoO) is developed as one efficient hydrogen evolution reaction (HER) electrocatalyst in alkaline media. The optimized CoMoO 4-x P x /CoO shows a small overpotential of 63 mV at 10 mA cm −2 for the HER in 1 M KOH. Combined characterization and density functional theory calculation, the active sites of CoMoO 4-x P x /CoO for HER are the surficial Co and Mo atoms that are linked by a P-OH structure.
Jian Wang,Xiaoyang Zhao,Yunfei Zhang,Ying Dong,Yuqin Yin,ZhangHu Yu,Guanren Ge,Jun Yu,Shichun Mu
Designing an affordable catalyst for the hydrogen evolution reaction (HER) in alkaline media remains a major challenge. In this study, we synthesized a Ru-CoMoO4–x/NF catalyst modified with ruthenium nanoclusters (Ru NCs) and oxygen vacancies (Ovs), using nickel foam (NF) as the substrate. X-ray photoelectron spectroscopy (XPS) analysis showed that introducing Ru nanoclusters effectively modified the catalyst’s electronic structure. A carefully controlled concentration of oxygen vacancies enhanced the catalyst’s stability, reduced electrochemical impedance, and promoted hydrogen evolution kinetics, thereby improving the intrinsic activity of Ru-CoMoO4–x/NF. In an alkaline freshwater medium, Ru-CoMoO4–x/NF displayed a low overpotential of 20 mV to achieve a current density of −10 mA cm–2, with a Tafel slope of 41.54 mV dec–1. The catalyst maintained stable performance with minimal degradation after 100 h in constant voltage tests and 180 h in multistep constant current tests. Moreover, in an overall water-splitting system, Ru-CoMoO4–x/NF∥Ru-CoMoO4–x/NF required only 1.606 V to drive −50 mA cm–2. This work presents a viable approach to enhancing the HER electrocatalytic performance of nonprecious metal oxides through the synergistic effects of Ru NCs and Ovs.
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