Interfacial Hydrogen Spillover on Pd-TiO₂ with Oxygen Vacancies Promotes Formate Electrooxidation

Abstract

Pd-based catalysts are crucial in direct formate fuel cells owing to their high stability and selectivity for the formate oxidation reaction (FOR) to CO 2 , avoiding carbonaceous poisoning species (e.g., CO ad , CH x ) in alkaline media. However, the kinetics of Pd-based electrocatalysts are considerably impeded by the unfavorable adsorption of hydrogen species (H ad ), which serve as the primary intermediators and occlude the active sites. Herein, we crafted electron-rich Pd nanoparticles on a TiO 2 support with oxygen vacancies (Pd/O v -TiO 2 ) to improve H ad desorption. The as-prepared Pd/O v -TiO 2 exhibited a high mass activity of 4.16 A mg Pd −1 , outperforming Pd/TiO 2 without oxygen vacancies and commercial Pd/C by 1.41 and 2.72 times, respectively. Experimental characterizations and density functional theory calculations revealed that the oxygen-vacant TiO 2 can concurrently downshift the d-band center of Pd and facilitate hydrogen spillover, thereby accelerating H ad desorption and FOR kinetics. Our findings provide a strategy to refine Pd-based catalysts for broader electrochemical uses.

Hydrogen Spillover Accelerates Electrocatalytic Semi-hydrogenation of Acetylene in Membrane Electrode Assembly Reactor

“…On the fcc phase, the rate-determining step (RDS) was found to be the dissociation of water with an energy barrier of 0.59 eV. In contrast, the water dissociation step on the bcc phase was energetically favorable, which is consistent with the Raman spectra results. − As a result, the RDS is shifted to the H-recombination step. However, there is only a minimal change in the energy barrier for the RDS, approximately 0.01 eV.…”

Synergy of W doping and oxygen vacancy engineering on d-band center modulation for enhanced gas sensing performance

“…Furthermore, the narrower E g could facilitate the excitation of d-band electrons from the valence band to the conduction band in the sample and achieve the modulation of the d-band center of the material. 44…”

Pd Nanoparticles Supported on N-Doped Porous Carbon Cathodes for the Catalytic Semideuteration of Alkynes

“…The conspicuous change implied that the ratio of pyridinic nitrogen to pyrrolic nitrogen can induce the formation of electron-rich palladium, thereby adjusting the original electronic structure of palladium in the Pd-NC composite material. This structural alteration holds crucial significance for modulating the semideuteration process of alkynes …”