There are still great challenges to prepare high‐efficiency Ru‐based catalysts that are superior to Pt/C under acidic conditions, especially under high current conditions. In this work, a series of surfactant‐free noble metal doped Ru/CNT (M‐Ru/CNT, M = Pt, Rh, Pd, Ir, CNT stands for carbon nanotube) are prepared by microwave reduction method in 1 minute with ≈3–3.5 nm in size for the first time. In 0.5 m H2SO4, the overpotential of Pt‐Ru/CNT (Pt: 4.94 at %) is only 12 mV. What's more, it also has much larger electrochemical surface area and intrinsic activity than Pt/C. Pt‐Ru/CNT still has an ultra‐small overpotential under high current density (113 mV at 500 mA cm−2, 155 mV at 1000 mA cm−2). At the same time, it possesses excellent stability regardless of high current or low current after the durability test of 100 h. Theoretical calculation also deeply reveals that Ru is the main adsorption site of H+. The comparison of the electronic structure of a series of noble metals adjusted by Ru shows that Pt has the most excellent Gibbs free energy of the adsorbed hydrogen and promotes the desorption of the product.

Phase engineering is a promising but challenging approach to construct PtFe‐based catalysts with efficient hydrogen evolution reaction (HER) performance. Herein, the authors successfully synthesize PtFe nanofoams with face center cubic (fcc) phase, with simple cubic crystalline (scc) phase and with the mixture phases of fcc and scc phases (PtFe‐mix) by hydrogen‐assisted calcination for the first time. By benchmarking the HER activity, PtFe‐mix exhibits excellent activity in 1.0 m KOH, requiring an overpotential of 28 mV to achieve 10 mA cm−2, which is better than the commercial Pt/C (34 mV). PtFe‐mix also possesses remarkable stability up to 24 h. Density functional theory calculations further verify that PtFe‐mix shows a more suitable d‐band center and lower energy barrier for the initial water dissociation, facilitating the HER process. This work provides a meaningful strategy to design PtFe‐based catalysts with efficient activity for hydrogen evolution.

No abstract

No abstract

Transition metal-based nanomaterials are regarded as promising catalysts due to low cost and abundant reserves. In particular, transition metal-based selenide exhibit excellent capability for oxygen evolution reaction (OER). However, the...

At present, the development of hydrogen evolution reaction (HER) catalysts with intrinsic activity higher than that of Pt/C still faces great challenges. In this work, we synthesized a series of ultrasmall (<5 nm) surfactant-free M–Ru2P@Ru/CNTs (M = Pt, Pd, Rh, and Ir; CNTs = carbon nanotubes) via a solvent-free microwave method in a household microwave oven within 1 min for the first time. Electronic and chemical effects caused by heterojunction and doping in M–Ru2P@Ru/CNTs can effectively promote HER. After optimizing the components and proportions, Pt–Ru2P@Ru/CNT with a Pt content of 9.5% (Pt0.095–Ru2P@Ru/CNT) exhibits the highest catalytic properties, with low overpotentials of 14 and 27 mV in 1 M KOH and 0.5 M H2SO4, respectively, outperforming most reported Ru-based catalysts. Moreover, the electrochemically active surface area (ECSA) of the Pt0.095–Ru2P@Ru/CNT can reach 165 m2/g. Also, turnover frequency (TOF) values under alkaline and acidic conditions are 21 and 54 s–1, respectively. The high current activity of the Pt0.095–Ru2P@Ru/CNT was also explored. Achieving current densities of 1000 mA cm–2 in alkaline and acidic electrolytes requires only 109 and 135 mV, respectively. Furthermore, the strong interaction between ultrasmall nanoparticles and CNTs can make nanoparticles firmly anchored on CNTs. After 120 h of stability testing under various conditions, they still retain excellent activity.

The excessive using of fossil energy has caused serious environmental pollution, and the development and utilization of new energy sources have been a continuing research direction of concern. The synergistic effect of Ni and Fe is beneficial to reduce the reaction energy barrier of oxygen evolution reaction (OER), therefore NiFe based catalyst represents a very promising non-precious metal OER catalyst. This minireview focuses on the optimization strategies for NiFe based catalysts, summarizes the research progress made in recent years, and discusses the mechanisms involved in these strategies. After composition and structure optimization, the catalytic activity and stability of NiFe based catalysts have been improved, which is beneficial to OER. Finally, the development direction and research prospect of NiFe based catalysts are provided with a reasonable outlook.