Effect of metal deposition sequence in carbon-supported Pd-Pt catalysts on activity towards CO2 electroreduction to formate

•Pd-Pt/C catalysts with different metal deposition sequences were prepared.•The deposition of Pt prior to Pd showed the highest formate production rate.•The mass activity of the best Pd-Pt/C catalyst was 21.5 times that of Pd/C at − 0.3 V.

Pd/C catalysts facilitate CO2 electroreduction to formate with high Faradaic efficiency at low overpotentials. However, they are prone to deactivation due to CO poisoning. In this work, three carbon-supported Pd-Pt catalysts with different metal deposition sequences are prepared and their efficacy towards formate production over the Pd surface is studied. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy results show that the surface composition and coordination number of Pd-Pd in carbon-supported Pd-Pt catalysts are greatly influenced by the order in which Pd and Pt nanoparticles (NPs) are deposited. The deposition of Pt NPs prior to Pd NPs on the carbon support gives the best results for formate production with high Faradaic efficiency.