Study On The Electrochemical Preparation Of Biomass Based High-value-added Chemicals 2,5-furanedicarboxylic Acid Using Nickel Based Oxides Supported On Carbon Felts

The high value utilization of biomass is a major demand for ecological environmental protection and social sustainable development.5-hydroxymethylfurfural（HMF）derived from lignocellulose is an important biomass platform compound,and its oxidation product,2,5-furanedicarboxylic acid（FDCA）,has broad application prospects as a precursor for biodegradable bioplastics.Electrochemical oxidation can efficiently convert HMF into FDCA in a green manner.In strong alkaline environments（p H=14）,nickel-based catalysts exhibit excellent catalytic activity and FDCA selectivity,but HMF is unstable in strong alkaline environments and the FDCA separation and purification costs are high.However,in non strongly alkaline environments（p H<14）,the activity of existing catalysts and the yield of FDCA are not ideal.In response to the above issues,the following research has been carried out in this paper:A method for preparing Ni O electrode（Ni O/CF）using carbon felt as substrate was established.Compared to carbon paper and carbon cloth,Ni O electrodes using carbon felt as a conductive substrate have lower HMF onset oxidation potential and higher current density.Ni O/CF exhibits excellent HMF oxidation performance in 0.1 M KOH（p H≈13）.When the electrode potential is higher than 1.39 V,the HMF conversion,FDCA yield,and Faraday efficiency of Ni O/CF are all close to 100%,and the Ni O/CF electrode exhibits excellent stability in terms of catalytic performance and electrode structure.When the electrode potential is lower than the formation potential of high-valence nickel species,Ni O/CF can catalyze the oxidation of HMF through a direct oxidation mechanism,and by increasing the electrode area,FDCA yield and Faraday efficiency>95%can be achieved at 1.30 V.In addition,the utilization of an anion exchange membrane as the separator of a dual chamber electrolyzer can effectively alleviate the changes in the p H value of the electrolyte during the HMF electrolysis process,maintain the anode at a high alkaline level,and facilitate the conversion of HMF to FDCA.Furthermore,the oxidation performance of nickel-based oxides supported on carbon felt in weak alkaline and neutral environments was studied.In 1 M Na HCO₃,the HMF conversion on Ni O/CF follows an indirect oxidation mechanism.At a potential of 1.497 V,the HMF conversion,FDCA yield,and Faraday efficiency of Ni O/CF can reach～100%,93.4%,and 70%,respectively,and Ni O/CF also exhibits good structural stability.However,in 0.1 M Na₂SO₄,Ni O/CF cannot effectively catalyze the conversion of HMF to high value-added products.In contrast,carbon felt supported nickel manganese bimetallic oxides（Ni-Mn-O/CF）can catalyze HMF conversion through a direct oxidation mechanism,with HMF conversion and FDCA yield reaching 99.7%and 37.2%respectively at 1.60 V.Due to the decrease in the p H value of the anolyte during the electrolysis process,significant loss of Ni is observed.