Mono-disperse PdO nanoparticles prepared via microwave-assisted thermo-hydrolyzation with unexpectedly high activity for formic acid oxidation

• Published in: Electrochimica acta 2020-01, Vol.329 (C), p.135166, Article 135166
• Main Authors: Li, Zuopeng, Song, Jili, Lee, Dong-Chan, Abdelhafiz, Ali, Xiao, Zhuojie, Hou, Zhaohui, Liao, Shijun, DeGlee, Ben, Liu, Meilin, Zeng, Jianhuang, Alamgir, Faisal M.
• Format: Article
• Language: English
• Subjects: Carbon black; Catalytic activity; Comparative studies; Dispersion; Formic acid; Formic acid oxidation; Fuel cells; Heat treatment; Nanoparticles; Organic chemistry; Oxidation; Palladium oxides; Thermo-hydrolyzation
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.135166

Without the backing of systematic comparative studies, it is generally accepted by the fuel cell community that Pd nanoparticles are superior to their Pd oxide counterparts towards the electrocatalytic oxidization of small organic molecules. We report an ecofriendly and straightforward approach to synthesizing PdO nanoparticles via an unprecedented microwave assisted thermo-hydrolyzation process. It is found that the catalyst remains in its oxidized state when heating in air and is converted into metallic state under the hydrogen treatment. Surprisingly, the mono-disperse PdO nanoparticles supported on carbon black demonstrates an unexpectedly high activity for FAO, with a mass activity of 2165 A g−1, surpassing that of commercial Pd nanoparticles (844 A g−1). Heat-treatment both in air and hydrogen deteriorates the catalytic activity to less than 50% that of the as-prepared. The better stability of the as-prepared PdO/C relative to commercial Pd is confirmed by repeated cyclic voltammetric as well as chronoamperometric evaluations. In this work, we report an ecofriendly and straightforward approach to synthesizing PdO nanoparticles via an unprecedented microwave assisted thermo-hydrolyzation process. Surprisingly, the PdO nanoparticles supported on carbon black demonstrated an unexpectedly high activity for formic acid oxidation, with a mass activity of 2165 A g−1 measured in 0.5 M H2SO4+0.5 M HCOOH at room temperature, surpassing that of commercial Pd nanoparticles (844 A g−1). [Display omitted] •Unprecedented microwave assisted thermo-hydrolyzation to synthesize mono-dispersed PdO (∼3 nm).•XPS/XAS confirmed the nature of the as-prepared PdO and conversion into metallic Pd in H2 treatment.•PdO/C exhibits an activity of 2165 A g−1 (vs. 844 A g−1 for Pd black) and high stability for FAO.