Bifunctional interstitial phosphorous doping strategy boosts platinum-zinc alloy for efficient ammonia oxidation reaction and hydrogen evolution reaction

It is still a lack of bifunctional catalysts for ammonia oxidation reaction (AOR) and hydrogen evolution reaction (HER) due to their different reaction mechanisms. In this work, P is doped into PtZn alloy by calcination with NaH₂PO₂ as P source to induce the lattice tensile strain of Pt and the electronic interaction between P and Zn, which optimizes the AOR and HER activity simultaneously. The sample with the optimal P content can drive the AOR peak current density of 293.6 mA·mg_Pt⁻¹, which is almost 2.7 times of Pt. For HER, the overpotential at −10 mA·cm⁻² is only 23 mV with Tafel slope of 34.1 mV·dec⁻¹. Furthermore, only 0.59 V is needed to obtain 50 mA·mg_Pt⁻¹ for ammonia electrolysis under a two-electrode system. Therefore, this work shows an ingenious method to design bifunctional catalysts for ammonia electrolysis.