Atomic doping and light irradiation promote anodic hydrogen evolution through furfural oxidation on Cu₂₊₁O/Cu nano-dendrites

Unlike cathodic hydrogen evolution, anodic hydrogen evolution enables the concurrent generation of hydrogen at both the anode and cathode. Achieving efficient hydrogen generation at the anode necessitates the use of high-performance electrocatalysts. In this study, it was found that atomic doping and light irradiation applied to Cu₂₊₁O/Cu nanodendrites are effective strategies for hydrogen generation through the anodic oxidation of furfural. The atomic palladium-doped Cu₂₊₁O/Cu nano-dendrites (Pd@Cu₂₊₁O/Cu NDs) were prepared by extremely diluting the Pd precursor in a copper salt solution using a one-pot electrodeposition technique. The coexistence of Cu₂₊₁O and Cu was verified by X-ray diffraction analysis. Electrochemical evaluations revealed that the peak of furfural oxidation on Pd@Cu₂₊₁O/Cu shifts negatively by 90 mV compared to that with Cu₂₊₁O/Cu. Importantly, visible light irradiation causes an increase of the peak current by over 200%. Comprehensive electrochemical and spectral investigations ascribe the exceptional catalytic performance of Pd@Cu₂₊₁O/Cu NDs for hydrogen production <i>via</i> furfural oxidation to several factors: a high density of oxygen vacancies that enhance molecular adsorption, a synergistic electronic interaction among Cu₂₊₁O, Cu and Pd that promotes charge transfer, and an optimal bandgap structure of the semiconductive composite electrocatalyst that enables efficient visible light absorption. This research advances the development of high-performance anodic hydrogen production from biomass-derived furfural using copper-based electrocatalysts.