Cooperative Rh-O₅/Ni(Fe) Site for Efficient Biomass Upgrading Coupled with H₂ Production

Designing efficient and durable bifunctional catalystsfor 5-hydroxymethylfurfural(HMF) oxidation reaction (HMFOR) and hydrogen evolution reaction (HER)is desirable for the co-production of biomass-upgraded chemicals andsustainable hydrogen, which is limited by the competitive adsorptionof hydroxyl species (OHads) and HMF molecules. Here, wereport a class of Rh-O-5/Ni(Fe) atomic site on nanoporousmesh-type layered double hydroxides with atomic-scale cooperativeadsorption centers for highly active and stable alkaline HMFOR andHER catalysis. A low cell voltage of 1.48 V is required to achieve100 mA cm(-2) in an integrated electrolysis systemalong with excellent stability (>100 h). Operando infrared and X-ray absorption spectroscopic probes unveil that HMFmolecules are selectively adsorbed and activated over the single-atomRh sites and oxidized by in situ-formed electrophilic OHads species on neighboring Ni sites. Theoretical studies further demonstratethat the strong d-d orbital coupling interactions between atomic-levelRh and surrounding Ni atoms in the special Rh-O-5/Ni(Fe) structure can greatly facilitate surface electronic exchange-and-transfercapabilities with the adsorbates (OHads and HMF molecules)and intermediates for efficient HMFOR and HER. We also reveal thatthe Fe sites in Rh-O-5/Ni(Fe) structure can promotethe electrocatalytic stability of the catalyst. Our findings providenew insights into catalyst design for complex reactions involvingcompetitive adsorptions of multiple intermediates.