Highly active and stable PdRE catalysts for enhancing the electrocatalytic methanol and ethanol oxidation

Abstract

Investigating how rare earth elements optimize the surface electronic states of noble metal-based electrocatalysts to enhance catalytic activity is of great importance, however, relevant studies on these reactions are significantly lacking. This study reports the synthesis of PdRE/C (RE = La, Nd, or Dy) catalysts and evaluated for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). PdLa/C exhibits superior catalytic activity, with a mass activity (MA) of 2.28 A mgPd-¹ for MOR, outperforming PdNd/C, PdDy/C, and commercial Pd/C-JM with a high stability retention of 95.6%. For EOR, PdLa/C achieves a MA of 5.67 A mgPd-¹, 31.5 times higher than Pd/C-JM. The results show that RE doping has reduced the electronic density of Pd and attenuated CO* adsorption at Pd sites, RE2O3 can improve the dispersion of Pd nanoparticles (NPs) and expose more catalytically active sites, and the optimal performance of PdLa/C is attributed to the strongest electronic synergism of Pd-La2O3. In addition, in-situ Fourier transform infrared (FT-IR) shows that PdLa/C has enhanced ethanol adsorption and C-C bond cleavage and improved CO₂ selectivity.