Rh/RhO x 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.10 (4), p.1891-1898
• Main Authors: Yang, Junjun, Xu, Liang, Zhu, Wenxiang, Xie, Miao, Liao, Fan, Cheng, Tao, Kang, Zhenhui, Shao, Mingwang
• Format: Article
• Language: English
• 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.