A general strategy for the preparation of transition metal carbon aerogel catalysts for efficient electro-oxidative valorization of HMF

The lack of high-performance, low-cost electrocatalysts is the key challenge for the production of 2,5 furandicarboxylic acid via electrocatalytic oxidation of 5-hydroxymethylfurfural. In this work, we report a novel approach for the preparation of highly dispersible transition metal catalysts loaded by carbon aerogel-loaded via a chitosan-transition-metal-ion coordination. The experimental results demonstrated that all of Ni²⁺, Co²⁺ and Cu²⁺ were able to coordinate with chitosan to form stable gels, which were then pyrolyzed to obtain highly dispersed transition metal-based catalysts (Co@NC, Ni@NC and Cu@NC) The Cu@NC exhibited the best HMFOR activity with high HMF conversion (nearly 100 %), FDCA selectivity (98.1 %), and Faraday efficiency (95.3 %). Mechanistic studies showed that Cu@NC was able to accumulate more effective oxidatively active species and thus achieve higher HMFOR current density compared to Co@NC and Ni@NC, and that the electrooxidation of HMF at the Cu@NC electrode followed the HMFCA oxidation pathway. This study provides a general and facile strategy for macropreparation of highly dispersible carbon aerogel-loaded transition metal catalysts for efficient electrocatalytic valorization of HMF.