Rh/RhO nanosheets as pH-universal bifunctional catalysts for hydrazine oxidation and hydrogen evolution reactions

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-01, Vol.1 (4), p.1891-1898
• Main Authors: Yang, Junjun, Xu, Liang, Zhu, Wenxiang, Xie, Miao, Liao, Fan, Cheng, Tao, Kang, Zhenhui, Shao, Mingwang
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d1ta09391f

Hydrazine oxidation reaction (HzOR)-assisted hydrogen evolution is a promising effluent treatment and energy conversion method for resolving the global energy shortage and environmental crisis. However, highly efficient and pH-universal electrocatalysts are still lacking to boost the sluggish kinetics of both the cathodic hydrogen evolution reaction (HER) and anodic HzOR. Here, Rh/RhO x nanosheets with Rh-O-Rh interfaces are fabricated by alkali-assisted synthesis and the H 2 reduction route. When they are employed as efficient bifunctional electrocatalysts, the Rh/RhO x nanosheets exhibit outstanding performance and stability for the HER and HzOR in pH-universal electrolytes. The two-electrode electrolyzer delivers a current density of 10 mA cm −2 with an ultra-low voltage of 0.068, 0.268, and 0.348 V in 1.0 M KOH/0.5 M N 2 H 4 , 1.0 M PBS/0.3 M N 2 H 4 and 0.5 M H 2 SO 4 /0.5 M N 2 H 4 , respectively. The performance can be maintained over 65 h for the HER and HzOR under neutral conditions. Density functional theory calculations indicate that the high activity is derived from the Rh-O-Rh interfaces. The regulation of the interface greatly improves the activity of the catalyst and reduces energy consumption, which is more conducive to the production of hydrogen. Rh/RhO x nanosheet electrocatalysts designed with Rh-O-Rh interfaces regulate the distance between the active site and the intermediate and effectively generate hydrogen in electrolytes of different pH values containing hydrazine.