Intermetallic PtSn Nanosheets with p–d Orbital Hybridization for Selective Hydroxylamine Electrosynthesis

The electrocatalytic nitrate reduction to hydroxylamine (NH₂OH) is a challenging catalytic process that has gained significant attention. However, its performance is hindered by the low selectivity of the electrocatalysts. Here, intermetallic PtSn nanosheets with p-d orbital hybridization have been synthesized, which significantly enhances the performance of electrocatalytic nitrate reduction to NH₂OH. The Faradaic efficiency of NH₂OH reaches a maximum of 82.83 ± 1.55% at -0.10 V versus the reversible hydrogen electrode (vs RHE), and the yield of NH₂OH achieves 6.15 ± 0.32 mmol h⁻¹ mgcat⁻¹ at -0.25 V vs RHE. Mechanistic studies reveal that p-d orbital hybridization between p-block Sn and d-block Pt effectively enhances nitrate adsorption and NH₂OH desorption to boost electrochemical NH₂OH synthesis. Given their excellent performance in the electrochemical synthesis of NH₂OH, PtSn nanosheets are utilized as the cathode in an alkaline-acid hybrid Zn-NO₃⁻ battery to facilitate the production of NH₂OH, achieving an NH₂OH FE of 80.42%.