Electrochemical upgrade of 5-hydroxymethylfurfural by C–N coupling over etched CuAu3@CuPd nanocubes†

5-Hydroxymethylfurfural (HMF), as a direct product of cellulose degradation, is an important biomass-based platform compound. The reductive amination of HMF is of significant industrial value among the upgrading reactions of HMF, which produces 5-hydroxymethylfurfurylamine (5-(aminomethyl)-2-furanmethanol, HMFA), an important intermediate of pharmaceutical and polymer materials. This work presents a facile one-pot synthesis of CuAu₃@CuPd nanocubes, which demonstrate exceptional activity and selectivity in the electrochemical co-reduction of HMF and NO₃⁻ to yield HMFA. Furthermore, an optimal faradaic efficiency of over 75% was achieved by etching the nanoalloy material with a moderate concentration of NOBF₄. The etching process exposed deeper CuPd active sites with a lattice distortion affected by the CuAu₃ core, thereby promoting the catalytic activity. Catalytic mechanism studies indicate that the C–N coupling reaction pathway involves the in situ generation and capture of the ^*NH₂OH intermediate. This work has paved a promising pathway for synthesizing high-value products from abundant biomass precursors utilizing the inorganic pollutant NO₃⁻ as a nitrogen source under ambient electrochemical conditions through the electrochemical co-reduction of HMF and NO₃⁻.