Ternary PtCoSn Catalyst with Regulated Intermediates Adsorption for Efficient Ammonia Electrolysis.

Ammonia electrolysis represents a green and economical strategy for hydrogen production, yet the progress is hindered by the lack of efficient catalyst to boost the kinetically sluggish ammonia oxidation reaction (AOR). Herein, ternary PtCoSn/C catalyst prepared by a facile wet-chemical reduction method is applied for AOR, which exhibits a specific activity of 0.87 mA cm , 3 times that of Pt/C. The highly enhanced activity is derived from the regulated intermediates adsorption on the PtCoSn/C surface, which is evidenced by in situ attenuated total reflection Fourier transform infrared measurements. The co-alloying of Co and Sn with Pt not only contributes to the weakened binding strength of *OH and *H species on Pt surface, enhancing the adsorption of NH and the related intermediates, but also facilitates the supply of OH to Pt sites, compensating for the fast consumption of OH in the double layer during AOR. Benefiting from its high activity for hydrogen evolution reaction, PtCoSn/C can be used as a bifunctional catalyst for ammonia electrolysis in a two-electrode system, which only requires 0.78 V to drive a current density of 10 mA cm. This work sheds light on developing efficient AOR catalysts, promoting hydrogen production from ammonia electrolysis.