Partially exposed RuP<sub>2</sub> surface in hybrid structure endows its bifunctionality for hydrazine oxidation and hydrogen evolution catalysis.

Li, Yapeng; Zhang, Jihua; Liu, Yi; Qian, Qizhu; Li, Ziyun; Zhu, Yin; Zhang, Genqiang · Sci Adv · 2020

basic_science · Level V

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Abstract

Replacing the sluggish anode reaction in water electrolysis with thermodynamically favorable hydrazine oxidation could achieve energy-efficient H<sub>2</sub> production, while the shortage of bifunctional catalysts limits its scale development. Here, we presented the scalable one-pot synthesis of partially exposed RuP<sub>2</sub> nanoparticle-decorated carbon porous microsheets, which can act as the superior bifunctional catalyst outperforming Pt/C for both hydrazine oxidation reaction and hydrogen evolution reaction, where an ultralow working potential of -70 mV and an ultrasmall overpotential of 24 mV for 10 mA cm<sup>-2</sup> can be achieved. The two-electrode electrolyzer can reach 10 mA cm<sup>-2</sup> with a record-low cell voltage of 23 mV and an ultrahigh current density of 522 mA cm<sup>-2</sup> at 1.0 V. The DFT calculations unravel the notability of partial exposure in the hybrid structure, as the exposed Ru atoms are the active sites for hydrazine dehydrogenation, while the C atoms exhibit a more thermoneutral value for H* adsorption.