Interface-Defect-Rich In-Mo Codoped Pd Metallene for Enhanced C1 Selectivity During Electrocatalytic Ethanol Oxidation

Direct ethanol fuel cells (DEFCs) are promising clean energy devices, but their efficiency is limited by the low C-C bond cleavage efficiency of Pd-based catalysts. Herein, we synthesized In-Mo codoped Pd metallene with rich interface defects via a simple wet-chemical method, which consists of face-centered cubic, intermetallic and amorphous phases. The catalyst's structure and ethanol electrooxidation reaction (EOR) performance was systematically characterized, and the mechanism was revealed by in situ ATR-FTIR, HPLC and DFT calculations. Results showed that the optimal PdInMo metallene exhibited a C1 pathway selectivity of 73.68%, which was 12.02 time that of commercial Pd/C. Its mass activity and specific activity were 4273.8 mA mg_Pd⁻¹ and 8.36 mA cm⁻², 2.38 and 1.34 times higher than those of undoped Pd metallene (1795.9 mA mg_Pd⁻¹ and 6.25 mA cm⁻²), 6.85 and 3.83 times higher than those of commercial Pd/C (624.2 mA mg_Pd⁻¹ and 2.18 mA cm⁻²), respectively, with excellent cycling stability (75.10% activity retention). The enhanced performance was attributed to the synergistic effect of In─Mo codoping and rich interface defects: strengthened OH* adsorption, weakened CO* adsorption, and reduced C─C bond cleavage energy barrier. This study provides a novel strategy for designing high-selectivity and high-activity Pd-based catalysts for EOR.