Dynamic Modulation of H· to H ⁻ &H ⁺ Enabled by Chemical Looping for Hydrogenation‐Dehydrogenation Tandem Reaction

Abstract

Abstract Coupling hydrogenation and dehydrogenation is of great significance, as both are pivotal bond reconstruction modes and co‐occur in about 10% of chemical syntheses. However, stoichiometric imbalance often necessitates exogenous hydrogen, which causes “seesaw effect” and inhibits dehydrogenation, challenging thermodynamics and kinetics of tandem process. Herein, we propose a dynamic strategy based on chemical looping to modulate hydrogen species. We designed Ru n @NiCu‐V M catalyst with metal vacancy (V M ) induced “electron allocator” properties, enabling reversible electron capture and release via chemical looping, which drives the neutral H· to convert into H − &H + , while simultaneously completing electron cycling. The converted H − &H + promote hydrogenation of polar ─C═N bonds in the tandem reaction of 5‐hydroxymethylfurfural to 2,5‐furandimethanamine, while neutral H· enhances the dehydrogenation rate by avoiding charge repulsion with H − &H + generated from dehydrogenation of ─CH 2 OH. The coupled hydrogenation‐dehydrogenation process achieves a 1.7‐fold rate enhancement, delivers 92% 2,5‐furandimethanamine yield, outperforms most reported catalysts, and exhibits broad substrate applicability.