Electrocatalytic Oxidation of Glucose Over Surface Modified Ni Open Cell Foams

Due to rising environmental concerns, reducing CO2 emissions to mitigate climate change has been one of the challenges of recent years. Reducing GHG emissions using biomass as a source to produce sustainable chemicals is a promising strategy. Biomass derived compounds, such as glucose, could be selectively electrooxidized to valuable chemicals while avoiding the exploitation of strong oxidants or highly pressurized environments. In this work, a study on glucose electrochemical oxidation over surface modified Nickel open cell foams has been conducted, to obtain value-added biomass derived chemicals like gluconic and glucaric acid. Modification of the Nickel open cell foams was achieved using calcination, electrodeposition, and hydrothermal synthesis techniques. The influence of applied potential, reaction time, and NaOH concentration were investigated. Nickel open cell foams were characterized by XRD, SEM-EDS, and Micro-Raman spectroscopy analysis. For the electrochemical characterization of the foams, CV experiments were conducted. Reaction products were analyzed with HPLC. According to the HPLC results, the oxidation reaction yielded mostly formic acid, arabinose, glycolic acid, lactic acid and most importantly gluconic acid. Considering different parameters, the highest gluconic acid selectivity, ~60%, was reached over the NiC500 electrode. By using NiNi electrode, the highest selectivity towards gluconic acid of 47% and 36% glucose conversion was achieved. The same catalyst achieved a selectivity towards gluconic acid of 38% and 39% glucose conversion with higher pH and lower potential. This study suggests the production of gluconic acid by the oxidation of glucose using nickel-based foams and marks the importance of the reaction parameters on the overall yield of the gluconic acid and the product distribution.