Highly Selective Oxidation of Carbohydrates in an Efficient Electrochemical Energy Converter: Cogenerating Organic Electrosynthesis

Abstract

The selective electrochemical conversion of highly functionalized organic molecules into electricity, heat, and added-value chemicals for fine chemistry requires the development of highly selective, durable, and low-cost catalysts. Here, we propose an approach to make catalysts that can convert carbohydrates into chemicals selectively and produce electrical power and recoverable heat. A 100% Faradaic yield was achieved for the selective oxidation of the anomeric carbon of glucose and its related carbohydrates (C1-position) without any function protection. Furthermore, the direct glucose fuel cell (DGFC) enables an open-circuit voltage of 1.1 V in 0.5 m NaOH to be reached, a record. The optimized DGFC delivers an outstanding output power Pmax =2 mW cm(-2) with the selective conversion of 0.3 m glucose, which is of great interest for cogeneration. The purified reaction product will serve as a raw material in various industries, which thereby reduces the cost of the whole sustainable process.

Electrocatalytic and Electroanalytic Investigation of Carbohydrates Oxidation on Gold-Based Nanocatalysts in Alkaline and Neutral pHs

“…12,25 We reported the use of "Bromide Anion Exchange" (BAE) method, [29][30][31] a surfactant-free approach, to develop a line-up of Au-Pd-Pt nanocatalysts able to oxidize efficiently glucose at low electrode potentials at various pHs. [32][33][34] It was also shown that monometallic Au enables a selective oxidation of a range of carbohydrates by their anomeric position and even in a cogeneration fuel cell; 13,35 however, it was postulated that the selectivity remained limited to Au that exhibits remarkable catalytic activity [36][37][38] toward aldehydes and hemiacetals oxidation. Herein, we examine the extended analysis on Au 100-x M x (M = Pd, Pt) catalysts by coupling electrochemical techniques with spectroscopic and chromatographic methods to unravel the outstanding ability of these electrocatalysts, enabling the acquisition of clear and precise information on the electrocatalytic reaction.…”

“…New type of devices so-called "co-generation or co-production" FCs arise from the possibility of reaching efficiently and simultaneously these two goals. 8,9,[11][12][13][14][15] For instance, the current platforms for H 2 production are largely based on fossil fuels (steam methane reforming, coal gasification), and lead to the emission of significant quantities of greenhouse gases (CO 2 and other carbon-based species in addition to the need of high temperatures), which apparently violates our original intention of reducing global warming by the employment of H 2 power. 16 Besides, the organic electrosynthesis is expected to replace, somehow, toxic or hazardous reagents, avoid large quantities of stoichiometric oxidizers and reducers as well as the in situ production of unstable and/or hazardous chemicals, which means that the waste originating from the used reagents is almost negligible.…”

“…Furthermore, the production of chemicals from pristine abundant organics (known as organic electrosynthesis) could also become an excellent idea to avoid excessive CO 2 emissions. [13][14][15]20,21 Abundant, renewable, and nontoxic, carbohydrates with potentially high energy density (4.35 kWh kg −1 for glucose) 6 represent a class of compounds that have received tremendous interests in electrocatalysis owing to the fact that these carbohydrates and cellulose/hemicellulose represent up to 70% of the biomass, an extensive and endlessly renewable resource. 13 For instance, gluconic acid from the selective glucose oxidation in a two-electron process is a mild organic acid that has received great interest in various fields such as food, pharmaceutical, and cosmetic industries.…”

“…[13][14][15]20,21 Abundant, renewable, and nontoxic, carbohydrates with potentially high energy density (4.35 kWh kg −1 for glucose) 6 represent a class of compounds that have received tremendous interests in electrocatalysis owing to the fact that these carbohydrates and cellulose/hemicellulose represent up to 70% of the biomass, an extensive and endlessly renewable resource. 13 For instance, gluconic acid from the selective glucose oxidation in a two-electron process is a mild organic acid that has received great interest in various fields such as food, pharmaceutical, and cosmetic industries. 13,22,23 Seminal investigations in electrocatalysis showed that the alkaline medium is the environment of choice for mono-and polyhydric alcohols electrooxidation.…”

“…13 For instance, gluconic acid from the selective glucose oxidation in a two-electron process is a mild organic acid that has received great interest in various fields such as food, pharmaceutical, and cosmetic industries. 13,22,23 Seminal investigations in electrocatalysis showed that the alkaline medium is the environment of choice for mono-and polyhydric alcohols electrooxidation. [24][25][26][27] Hence, performing selectively these reactions in order to produce chemicals of interests within a cogeneration configuration is an excellent tool to cut down the H 2 production cost.…”