To explore highly active non-noble electrocatalysts toward full water splitting, the incorporation of other metal elements to the host electrocatalyst is required, especially for previously reported highly efficient MoO2–MoNi4 (MoNi in short). Herein, to lessen the energy cost in full water splitting, the vanadium-incorporated MoO2–MoNi4 (VMoNi in short) hybrid nanoarray self-supported on nickel foam is prepared through a simple way. Compared with the Mo–Ni binary electrocatalyst, vanadium incorporation can obviously boost oxygen evolution reaction (OER) activity while almost keeping the perfect hydrogen evolution reaction (HER) ability, for it merely requires 202 and 17 mV for 10 mA cm–2 working current density toward OER and HER, respectively. Furthermore, it displays outstanding performance toward full water splitting, merely requiring 1.45 V for 10 mA cm–2 and 1.61 V for 100 mA cm–2 in water electrolysis with keeping the voltage stable in tens of hours at 250 mA cm–2. This work highlights the significance in large-scale hydrogen production from water electrolysis with the help of exploring non-noble materials, an important milestone in converting the renewable energy to hydrogen energy.
Qiong Zhang,Ruixue Zhang,Yingxiu Zhao,Tiantian Sun,Jianyang Gao,Guang-Rui Xu,Zexing Wu,Yu Yang,Lei Wang
Comprehensive Summary Realizing the hydrogen economy by water electrolysis is an attractive approach for hydrogen production, while the efficient and stable bifunctional catalysts under high current densities are the bottleneck that limits the half-cell reactions of water splitting. Here, we propose an approach of hydrothermal and thermal annealing methods for robust MoO 2 /MoNi 4 @Ru/RuO 2 heterogeneous cuboid array electrocatalyst with multiplying surface-active sites by depositing a monolayer amount of Ru. Benefiting from abundant MoO 2 /MoNi 4 @Ru/RuO 2 heterointerfaces, MoO 2 /MoNi 4 @Ru/RuO 2 heterogeneous cuboid array electrocatalysts effectively drive the alkaline water splitting with superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) performances. The synthesized MoO 2 /MoNi 4 @Ru/RuO 2 has high HER activity, which realizes the working overpotentials of 48 mV at 50 mA·cm –2 , further achieving overpotentials of 230 mV for industry-level 1000 mA·cm –2 in alkaline water electrolysis. Moreover, it also showed an enhanced OER activity than commercial RuO 2 with a small overpotential of 280 mV at 200 mA·cm –2 in alkaline media. When building an electrolyzer with electrodes of (–)MoO 2 /MoNi 4 @Ru/RuO 2 IIMoO 2 / MoNi 4 @Ru/RuO 2 (+), a cell voltage of 1.63 V and 1.75 V is just required to support the current density of 200 mA·cm –2 and 500 mA·cm –2 in alkaline water electrolysis, much lower than that of the electrolyzer of (–)Pt/CIIRuO 2 (+). This work demonstrates that MoO 2 /MoNi 4 @Ru/RuO 2 heterogeneous nanosheet arrays are promising candidates for industrial water electrolysis applications, providing a possibility for the exploration of water electrolysis with a large current density.
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