Electro-catalytic oxidation of hemicelluloses at the Au electrode

Abstract

The recently reported electro-catalytic reaction mechanism for the oxidation of cellulose is proposed to work also for the electro-oxidation of other polysaccharides (e.g. hemicelluloses). In this report, the electrochemical reactivity of some hemicelluloses (xylan, arabinoxylan, glucomannan, xyloglucan, and glucuronoxylan) in 1.3 M NaOH solution is described. The electrochemical property of each of the studied hemicelluloses at the Au electrode surface was characterized by cyclic voltammetry. Xylan, xyloglucan and glucuronoxylan were found to be electrochemically active. Electrochemical properties of xylan were further studied by electrochemical impedance spectroscopy. The electrochemical reaction products of xylan, obtained by extensive electrolysis of the xylan solution by cyclic voltammetry, were characterized by FTIR spectroscopy, (13)C-NMR spectroscopy, SEM and TEM. The structural studies suggest that the oxidized xylan is a functional material where some of the OH-groups have been oxidized to carboxyl groups making that part of the oxidation product soluble in water under ambient conditions (23 °C, pH 7). The other part remains insoluble in water and contains Au nanoparticles. This work indicates that other polysaccharides than cellulose can also be electrochemically oxidized.

Electrosynthesis of Biobased Chemicals Using Carbohydrates as a Feedstock

“…The electrochemical oxidation of cellulose has also been reported using a gold electrode, in alkaline media (1.3 M NaOH). [12,14]. Although the oxidized products were not clearly identified, it is worth noting that the authors proposed a detailed mechanism to explain the interaction between cellulose and the various gold species formed at the surface of the electrode.…”

Photocatalytic alginate fuel cells for energy production and refining of macroalgae

“…In addition, biomass has the potential to be used as a feedstock for many basic chemicals in a process known as biorening, analogous to petrochemical rening, which produces chemicals ubiquitous in industrial and consumer products. 1,2 However, most sources of biomass used currently, such as sugarcane and corn, would otherwise be used as food; thus, their use as fuel increases crop prices, limiting the use of these fuel sources. As such, much attention has been given to the utilization of inedible and currently unused biomass, including waste wood, sugarcane bagasse, and sewage sludge.…”

Specific Electrocatalytic Oxidation of Cellulose at Carbon Electrodes Modified by Gold Nanoparticles

“…Moreover, the mechanism of the reaction that occurs on a pristine bare Au electrode surface has been investigated in detail . It has been suggested that the electrochemical processes that occurs on a Au electrode can also be applied in the direct oxidation and functionalization of hemicellulose . As the electro‐oxidation of the polysaccharides takes place at a specific interface, it is important to study the influence of the surface structure on the catalytic activity in terms of the electrochemical oxidation properties of the polysaccharides.…”

“…[4] It has been suggested that the electrochemical processes that occurs on aA u electrode can also be applied in the direct oxidation and functionalization of hemicellulose. [5] As the electro-oxidation of the polysaccharides takes place at as pecific interface, it is important to study the influence of the surfacestructure on the catalytic activity in terms of the electrochemical oxidation properties of the polysaccharides. It is expected that the electrochemical reaction properties of polysaccharides, which include cellulose and hemicelluloses, can be alteredb yc ontrolling the electrode-electrolyte interface.…”