Synergistic effect of porous carbon and nickel species for selective hydrogenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran: structure-performance relationships and kinetic insights

Ni/AC prepared by impregnation and in situ chemical reduction on porous carbon • AC anchors and disperses Ni uniformly, enabling an interfacial *H-rich environment • Ni/AC delivers efficient HMF hydrogenation with up to 96.8% DMF selectivity • DFT indicates Ni strongly activates H 2 while moderately adsorbing HMF • Kinetics identifies BHMF→MFA HDO as the rate-determining step guiding DMF formation Developing low-cost catalytic systems for the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) is of practical significance. Rational coupling between non-noble metal sites and carbon microenvironments is critical to control hydrogen activation, hydrogenation kinetics, and product selectivity. Here, we construct a series of non-noble metal/porous carbon catalysts (M/AC, M = Ni, Fe, Co, Cu) by impregnation followed by in-situ chemical reduction using biomass-derived porous carbon as the platform and systematically elucidate their structure-performance relationships. Multiscale characterizations collectively establish an oxygen-functionality/pore-confinement microenvironment that governs Ni dispersion and metal-support coupling, thereby tuning interfacial *H availability and its turnover relevant to hydrogenation. Consequently, Ni/AC delivers efficient HMF conversion with a DMF selectivity up to 96.8%. Density functional theory indicates that Ni simultaneously enables favorable H 2 adsorption/dissociation and moderate HMF binding, facilitating the formation of a locally *H-enriched interfacial region. Kinetic fitting further identifies the hydrogenation of 2,5-bis(hydroxymethyl)furan (BHMF) to 5-methyl-2-furanmethanol (MFA) as the rate-determining step, rationalizing the preferential DMF pathway under Ni/AC. On this basis, we propose a transferable porous carbon-Ni coupling strategy in which support oxygenated functionalities and pore architecture co-modulate metal dispersion and interfacial hydrogen chemistry, providing guidance for non-noble metal catalysis toward selective hydrogenation of HMF to DMF. Schematic illustration of the waste to catalyst design concept: coconut shell derived porous activated carbon as a stable support for non-noble metals (M = Ni, Fe, Co, Cu) via impregnation and low-temperature in situ chemical reduction, and applying prepared M/AC catalysts to selective HMF upgrading toward DMF through an interfacial *H-rich microenvironment. Download: Download high-res image (188KB) Download: Download full-size image