Work

Spectral-architectural tuning of Au–Pd nanocatalysts for on-demand photocatalytic HMF oxidation

Year: 2026

Type: article

Abstract: The selective oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) into high-value intermediates and 2,5-furandicarboxylic acid (FDCA) is a key process in sustainable polymer manufacturing. However, conventional thermal processes often require harsh conditions that promote non-selective degradation or high-energy demand. Herein, we establish a comprehensive structure-light-reactivity relationship for the photo-assisted oxidation of HMF in water by systematically comparing zirconia-supported Au–Pd alloy and core–shell nanoarchitectures under thermal and photocatalytic conditions. Monochromatic irradiation at 365, 450, and 523 nm was employed to decouple the contributions of UV photolysis, visible-light activation, and localized surface plasmon resonance (LSPR) of gold. We identify the surface Pd density as the primary structural descriptor governing oxidation depth, while the nanoarchitecture dictates the light-harvesting mechanism. Under thermal conditions, the alloy configuration dominates through synergistic electronic and geometric ensemble effects. Intriguingly, this catalytic ranking undergoes a fundamental reversal under 450 nm irradiation, with the Pd-rich core–shell architecture (AuPd 500 @ZrO 2 ) outperforming the alloy and achieving near-complete HMF conversion (99.1%), together with significant selectivity toward FDCA (24.9%) and FFCA (25.9%). At 523 nm, close to the Au LSPR maximum, the ranking reverses again in favor of the alloy configuration. This double reversal demonstrated a wavelength-gated reaction steering mechanism where, for a fixed Au-Pd composition, nanoarchitecture alone determines the activity and selectivity. Crucially, the wavelength-dependent response enables precise, external control over product distributions without altering the baseline reaction parameters. Operating in an aqueous medium under mild conditions with low precious-metal loadings, this work demonstrates that combining rational nanostructure design with targeted spectral inputs offers a powerful tool for overcoming conventional thermal Sabatier limitations in renewable carbon upgrading.

Source: Materials Today Communications

DOI: 10.1016/j.mtcomm.2026.116309