The development of cost-effective hydroxide exchange membrane fuel cells is limited by the lack of high-performance and low-cost anode hydrogen oxidation reaction catalysts. Here we report a Pt-free catalyst Ru7Ni3/C, which exhibits excellent hydrogen oxidation reaction activity in both rotating disk electrode and membrane electrode assembly measurements. The hydrogen oxidation reaction mass activity and specific activity of Ru7Ni3/C, as measured in rotating disk experiments, is about 21 and 25 times that of Pt/C, and 3 and 5 times that of PtRu/C, respectively. The hydroxide exchange membrane fuel cell with Ru7Ni3/C anode can deliver a high peak power density of 2.03 W cm−2 in H2/O2 and 1.23 W cm−2 in H2/air (CO2-free) at 95 °C, surpassing that using PtRu/C anode catalyst, and good durability with less than 5% voltage loss over 100 h of operation. The weakened hydrogen binding of Ru by alloying with Ni and enhanced water adsorption by the presence of surface Ni oxides lead to the high hydrogen oxidation reaction activity of Ru7Ni3/C. By using the Ru7Ni3/C catalyst, the anode cost can be reduced by 85% of the current state-of-the-art PtRu/C, making it highly promising in economical hydroxide exchange membrane fuel cells.

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The design of highly active, stable, and low‐cost electrocatalysts for the oxygen evolution reaction (OER) in proton exchange membrane water electrolyzer remains a challenge. RuO2 shows relatively low cost but poor stability. Here, the critical role of sulfate anion doping in promoting OER activity and stability of RuO2 is reported. Coupled with the Fe cation doping, the sulfate‐functionalized RuFeOx (S‐RuFeOx) displays a remarkable OER performance with a low overpotential of 187 mV at 10 mA cm−2 in acid, and much enhanced stability. The excellent OER activity of S‐RuFeOx is attributed to the dual positive effects that the sulfate dopants weaken the adsorption of the *OOH intermediate, and Fe dopants promote the deprotonation of chemisorbed water molecules to form *OOH. The enhanced stability is in part due to the sulfate dopants which stabilize the lattice oxygen. These results demonstrate that the anion and cation co‐doped RuO2 is a promising candidate for highly efficient OER electrocatalysts.

Proton exchange membrane water electrolyzer can sustainably and environmentally friendly produce hydrogen. However, it is hindered by the lack of high-performance anode catalysts for oxygen evolution reaction (OER) in acid electrolyte. Herein, IrCuNi deeply concave nanocubes (IrCuNi DCNCs) are successfully synthesized from the selective etching of the facet of cubic nanoparticles, and they significantly boost the OER. The obtained IrCuNi DCNCs show high activity toward OER in the acidic electrolyte, which only requires an overpotential of 273 mV to achieve the OER current density of 10 mA cm −2 at a low Ir loading of 6.0 μg Ir cm −2 . The precious metal based mass activity is 6.6 A mg Ir −1 at 1.53 V, which is 19 times as high as that of pristine Ir. It demonstrates that the outstanding catalytic performance is beneficial from the well-defined multimetal concave nanostructures, which may shed light on the fabrication of efficient water electrolyzers.

The phase of nanocrystals has a key role in the modulation of catalytic properties. Uniform and well-crystallized nickel phosphide nanocrystals with controlled phases (Ni P , Ni P, and Ni P ) and narrow size distributions are synthesized by a wet chemical method. The phases of the as-synthesized nickel phosphide nanocrystals are controlled by the P/Ni precursor molar ratio, heating process, and time of reaction. Rarely reported nearly monodisperse 5.6 nm Ni P nanocrystals are successfully synthesized and show superior hydrogen evolution reaction (HER) activity. Only a low overpotential of 103 mV is required to achieve the HER current of 10 mA cm at a low catalyst loading of 0.12 mg cm . The high HER activity is attributed to the high quality of the as-obtained Ni P nanocrystals, which have the electronic effect from the Ni P phase and also high surface area owing to the small particle size. A systematic study of the controlled synthesis of nickel phosphide nanocrystals is shown in this paper, and the HER catalytic activity is improved through the phase- and size-controlled synthesis of nanocrystals.