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_ECSA⁻², 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 NH₃ 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⁻². This work sheds light on developing efficient AOR catalysts, promoting hydrogen production from ammonia electrolysis.