Electrocatalytic selective oxidation of glycerol to tartronate on Au/C anode catalysts in anion exchange membrane fuel cells with electricity cogeneration

• Cogeneration of tartronate (high yield) and electricity was achieved in AEM-DGFC.
• Electrode structure and operation conditions can tune anode potential.
• The oxidation activity of desorbed glycerate, tartronate, mesoxalate on Au/C is low.
• Tartronate is generated through direct adsorbed C3 intermediates oxidation.
• Au/C catalysts with different particle sizes show very close tartronate yields.

Sustainable cogeneration of tartronate (high yield of 61.8%) and electrical energy (1527 J, 12 h) has been achieved from direct electrocatalytic oxidation of glycerol on Au/C in a 5 cm2 anion exchange membrane-direct glycerol fuel cells (AEM-DGFCs). The electrode structure and reaction conditions exhibited strong effects on the anode potential, which can be tuned to <0.45 V in favor of oxidizing two primary OH groups of glycerol while minimizing over-oxidation of the secondary OH and CC bond cleavage, thereby promoting the tartronate production. The relatively low activity of partial oxidation products (glycerate, tartronate, mesoxalate) on Au/C revealed in half cell indicates that the tartronate generation in AEM-DGFCs is through direct adsorbed C3 intermediates oxidation. Mass transport of reactants and reaction intermediates governed by the operational conditions was also found to play a critical role in regulating reaction rate and the desired products selectivity. Furthermore, Au/C prepared via aqueous phase reduction method (Au/C-AQ) was compared with organic phase nanocapsule method (Au/C-NC), and it shows the residual surfactants have little effect on the tartronate yield.

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