Electro-oxidation of formate-based solutions on Au/Pd core–shell nanoparticles – Experiment and simulation

Au/Pd core–shell nanoparticles (NPs) were employed to study electro-oxidation mechanism of formate-based solutions. A series of combined studies including Raman spectroscopy, electrochemical stripping analysis, and computational simulations were conducted to understand electro-oxidation of formate-based solutions on the Au/Pd NPs. Compared to the commercial Pd black, the Au/Pd NPs showed superior catalytic activities, especially when using concentrated formate solutions. CO stripping test in conjunction with in situ Raman studies showed a lower oxidation potential (0.6 V vs. Ag/AgCl) of CO on the Au/Pd NPs than the Pd black (>0.6 V). This indicated a strong electronic coupling between Au and Pd in the core–shell NPs which could enhance the oxidation of formate species. In addition, theoretical studies suggested lower formate and hydroxyl coverages at the same applied potential for the Au/Pd NPs than the Pd black in the formate-based solutions, shedding lights on their superior formate-oxidizing ability.