Recovered gold on biomass-based hierarchical porous carbon as a catalyst for 5-hydroxymethylfurfural oxidation

Abstract

The chemical utilization of biomass and waste as resources has attracted significant attention. Biomass-derived 5-hydroxymethylfurfural (HMF) can be used to produce high-value-added 2,5-furandicarboxylic acid (FDCA). However, it remains a challenge to develop effective and inexpensive catalysts. Herein, several gold catalysts were prepared using gold leachate from waste printed circuit boards (PCBs), in which N, S co-doped hierarchical porous carbon (BNS-HPC), without N and S doping (B-HPC), without hierarchical porous structure (BNS-PC) derived from waste biomass as well as commercial activated carbon (CAC) as supports, respectively. The effects of different supports on the size of gold nanoparticles, surface area, porous structures, distribution of gold atoms and catalytic preparation of FDCA were explored. The catalyst BNS-HPC@^recAu₃ stood out, with the lowest activation energy of 8.65 kJ mol⁻¹. The mass ratios of the support and gold in the raw materials were optimized, and the catalyst BNS-HPC@^recAu₂ with the smallest gold nanoparticle size (1.7 nm) exhibited outstanding catalytic performance, with the FDCA yield reaching 97.3% under a standard pressure of oxygen gas. The stability of the catalyst was tested, and the yield remained above 95% after recycling 10 times. This study provides an outstanding example for the reuse of biomass and waste resource.