Ultrafine Pd3Pb intermetallic nanowires with Mott–Schottky effect achieve a complete oxidation pathway for methanol oxidation catalysis

Abstract

Increasing the number of active sites can enhance activity for the methanol oxidation reaction (MOR), yet achieving a high density of active sites that can simultaneously regulate the adsorption of *OH and *CO remains highly challenging. Herein, a new class of intermetallic Pd₃Pb/N_xC_y with a high density of active sites that can simultaneously regulate the adsorption of *OH and *CO by the Mott–Schottky (M–S) effect was synthesized, and its alkaline MOR was studied. The MOR activity of optimized Pd₃Pb IM/MNC (Pd₃Pb intermetallic compound loaded on moderately N-doped C, with M–S effect) is 17.83 A mg⁻¹_Pd, which is 6.5 times higher than the 2.76 A mg⁻¹_Pd of Pd₃Pb IM/C (without M–S effect). The ECSA of Pd₃Pb IM/MNC (95.2 m² per gram of Pd) is higher than that of Pd/C (28 m² per gram of Pd). In addition, Pd₃Pb IM/MNC could achieve a power density of 225.5 mW cm⁻² while maintaining stable discharge performance (31.9% attenuation at 0.8 V (vs. RHE) for 10 hours). Experimental and theoretical studies have shown that the adsorption of *CO was appropriately attenuated by pyrrolic-N-Pd sites, and the adsorption of *OH was enhanced by pyridinic-N-Pb sites.