Reduction-induced non-monotonic Cu redispersion on hydroxyapatite creates functionally differentiated interfaces for furfural hydrogenation

Cu on HAP aggregates then redisperses non-monotonically upon reduction. • Reconstructed interface stabilizes Cu 0 /Cu + and HPO 4 2- units. • Interfacial synergy drops E a from 88.1 to 69.3 kJ/mol, sharply enhancing activity. • H 2 reaction order drops from 1.20 to 0.25 after interfacial reconstruction. • DFT unveils Cu dissociating H 2 and adjacent Ca polarizing the carbonyl group. Constructing non-noble-metal hydrogenation catalysts with high activity, chemoselectivity, and durability under mild conditions is a key challenge in biomass valorization. While strong metal–support interactions on hydroxyapatite (HAP) typically involve noble metals via oxidative pathways, we report a reduction-induced interfacial reconstruction for Cu-HAP. During temperature-programmed reduction, Cu shows non-monotonic evolution: aggregation then redispersion into an anchored state at 600 °C, bypassing sintering. Spectroscopic and DFT reveal that HAP retains long-range order, while the Cu–HAP boundary stabilizes Cu 0 /Cu + and HPO 4 2- , enabling cooperative H 2 dissociation and carbonyl polarization. The optimized catalyst achieves quantitative furfural conversion with > 99% furfuryl alcohol selectivity (80 °C, 1.5 MPa H 2 ). Kinetic benefits include decreased E a (88.1→69.3 kJ/mol) and shifted H 2 order (1. 2 0→0.25). The catalyst also maintains stable performance over five cycles with negligible leaching. These findings highlight the distinctive role of HAP's Ca–PO 4 –OH environment in reduction-induced Cu redistribution and interfacial reconstruction, providing new insights into the design of cooperative metal–support interfaces for selective hydrogenation. Download: Download high-res image (248KB) Download: Download full-size image Temperature-programmed reduction induces non-monotonic redispersion of Cu on hydroxyapatite, producing a reconstructed interfacial boundary with stabilized Cu 0 /Cu + and HPO 4 2- species. DFT indicates cooperative catalysis at this interface: Cu activates H 2 while adjacent Ca polarizes the carbonyl group. The decrease in apparent activation energy (88.1–69.3 kJ/mol) and the shift in H 2 reaction order (1.20–0.25) underlie the quantitative furfural conversion and > 99% furfuryl alcohol selectivity achieved under mild conditions (80 °C, 1.5 MPa H 2 ).