Insight into degradation mechanism of Pd nanoparticles on NCNTs catalyst for ethanol electrooxidation: A combined identical-location transmission electron microscopy and X-ray photoelectron spectroscopy study

Abstract Herein, we report a facile method to prepare palladium nanoparticles (Pd NPs) anchored on nitrogen-doped carbon nanotubes (Pd/NCNTs) with particle size distribution uniformed. The Pd/NCNTs exhibits excellent ethanol oxidation reaction (EOR) mass activity of 2,489 A g−1, which is 5.1 times higher than commercial Pd/C. However, the anodic reaction of EOR suffers from poor efficiency and low durability. In order to solve the problem of low durability and have better understanding of the degradation mechanism of anodic catalysts, identical-location transmission electron microscopy (IL-TEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements were carried out. These were applied to Pd/NCNTs catalyst under EOR in alkaline media. The results showed that the leaching of Pd NPs and the reduction of surface metallic Pd0 were the main reasons for the decreased EOR activity. These findings provide practical guidance for the development of catalysts with higher activity and stability for energy conversion.