Enhanced electrooxidation of glucose at nano-chitosan–NiOOH modified GC electrode: fuel blends and hydrocarbon impurities

Abstract

The current study addresses, for the first time, the promoting effect of some selected fuel blending components, such as methanol (MeOH), ethanol (EtOH) and acetaldehyde (ACTA), on the glucose electrooxidation at a nano-chitosan–NiOOH modified GC electrode (nano-CS–NiOOH/GC). Blending glucose with different molar ratios of MeOH, EtOH and ACTA results in a significant enhancement in the fuel utilization, NiOOH oxidation capacity and turnover number of oxidized glucose molecules compared to the pure fuels. For instance, the use of glucose fuel blends composed of 40% of glucose with 60% of either MeOH, EtOH and ACTA results in 10, 8 and 5 times higher glucose activity of the nano-CS–NiOOH/GC electrode compared to using glucose as a pure fuel, respectively. In addition, the nano-CS–NiOOH/GC electrode shows a higher tolerance towards chloride ions poisoning compared to the NiOOH/GC electrode. The existence of minute amounts of hydrocarbon impurities, such as acetonitrile stemming from degradation of fuel cell components, results in significant enhancement of the glucose electrooxidation at the nano-CS–NiOOH/GC. In contrast, the presence of any of those hydrocarbon impurities results in a significant decrease of the NiOOH/GC electrode activity indicating the essential role of chitosan. Chitosan is believed to improve the catalytic activity and durability via stabilizing the nickel oxyhydroxide phase (β-NiOOH), which may be active for the reaction.