Modulating d-Orbital electronic configuration via metal-metal oxide interactions for boosting electrocatalytic methanol oxidation

Synergistically improvement of the catalytic activity, durability and anti-CO poisoning via the metal–metal oxide strong interactions between PtFe NPs and CeO2 and the oxygen vacancies in CeO2. [Display omitted] •Pt3Fe@CeO2/MWCNTs exhibited high activity, stability, and CO tolerance during MOR.•Strong metal–metal oxide interaction between PtFe NPs and CeO2 can stabilize PtFe NPs against migration/agglomeration.•The d-orbital electronic configuration of Pt is optimized by combining the PtFe intermetallic with metal–metal oxide interaction.•The PtFe intermetallic coupled with oxygen vacancies in CeO2 facilitates the adsorption of *OH and oxidation of *CO, boosting the performance of MOR. Coordinating the interfacial interaction between Pt-based nanoparticles (NPs) and supports is a significant strategy for the modulation of d-orbital electronic configuration and the adsorption behaviors of intermediates, which is of critical importance for boosting electrocatalytic performance. Herein, we demonstrated a specific synergy effect between the ordered PtFe intermetallic and neighboring oxygen vacancies (Ov), which provides an “ensemble reaction pool” to balance the barriers of both the activity, stability, and CO poisoning issues for the methanol oxidation reaction (MOR). In our proposed “ensemble reaction pool”, the deprotonation of methanol occurs on the Pt site to form the intermediate *CO, where the strain derived from the PtFe intermetallic could alter the d-orbital electronic configuration of Pt, intrinsically weakening the *CO adsorption energy, and Ov in CeO2 promote hydroxyl species (*OH) adsorption, which will react with *CO, facilitating the dissociative adsorption of *CO, thus cooperatively enhancing the performance of MOR. The X-ray absorption fine structure (XAFS) analyses reveal the electron transfer in CeO2 and then convert Ce4+ to Ce3+. The density functional theory (DFT) calculations revealed that introducing Fe induces strain could modify the d-band center of Pt, and thus lower the energy barrier of the potential-determining step. Meanwhile, the introduction of CeO2 can favor the *OH adsorption, speeding up the oxidation and removal of *CO blocked at the Pt site. Furthermore, the determined atomic arrangement and surface composition of PtFe intermetallic further guarantee the stability of MOR by suppressing less-noble metal into the electrolyte.