One Dimensional AuAg Nanostructures as Anodic Catalysts in the Ethylene Glycol Oxidation

Abstract

Direct alcohol fuel cells are highly promising as efficient power sources for various mobile and portable applications. However, for the further advancement of fuel cell technology it is necessary to develop new, cost-effective Pt-free electrocatalysts that could provide efficient alcohol oxidation and also resist cross-over poisoning. Here, we report new electrocatalytic materials for ethylene glycol oxidation, which are based on AuAg linear nanostructures. We demonstrate a low temperature tunable synthesis that enables the preparation of one dimensional (1D) AuAg nanostructures ranging from nanowires to a new nano-necklace-like structure. Using a two-step method, we showed that, by aging the initial reaction mixture at various temperatures, we produced ultrathin AuAg nanowires with a diameter of 9.2 ± 2 and 3.8 ± 1.6 nm, respectively. These nanowires exhibited a high catalytic performance for the electro-oxidation of ethylene glycol with remarkable poisoning resistance. These results highlight the benefit of 1D metal alloy-based nanocatalysts for fuel cell applications and are expected to make an important contribution to the further development of fuel cell technology.

Effect of Anode Material on Electrochemical Oxidation of Low Molecular Weight Alcohols—A Review

“…One of the most popular methods for increasing the ESA is the usage of catalytic material in the form of nanoparticles because of their high surface-to-volume ratio, which results in higher activity and immunity to poisoning in the final material [ 22 , 23 , 24 ]. There are almost endless possibilities regarding the shapes of nanomaterials, but the most popular ones are one-dimensional nanomaterials (nanowires) [ 25 , 26 ], nanocubes [ 24 , 27 ], nanocrystals [ 23 , 28 , 29 , 30 , 31 ], spheres [ 23 , 32 ] and hexagons. Core–shell materials, like core–shell nanorods presented in Figure 2 , are a special part of nanomaterials because their specific structure strongly changes the reactivity of the final material.…”

“…Among the small organic molecules that can act as fuel for proton-exchange membrane fuel cells (PEMFCs), ethylene glycol is one of the most promising candidates. Ethylene glycol has low toxicity [ 28 , 90 , 161 ], low membrane penetration [ 25 , 85 , 90 , 108 , 161 ], high-energy-density [ 25 , 161 ] and relatively high reactivity in ambient temperatures [ 28 , 161 ], which are all valuable features for fuel in PEMFCs.…”

“…Additionally, EG is safer to work with than methanol and ethanol because it has a higher boiling point and higher volumetric capacity (see Table 1 ). Furthermore, because of the larger size of a single EG molecule, the membrane crossover is much smaller than in the case of methanol, which enhances the process efficiency because of the weaker cathodic poisoning effect [ 25 , 85 , 90 , 108 ].…”

“…The process of ethylene glycol production has been known since 1859, but its industrial-scale production began during World War I when it was used during the production of explosive materials as a substitute for glycerol [ 90 ]. Currently, it is a very important chemical that is widely used, i.e., in the automobile industry as a cooling agent [ 25 , 90 , 162 ] and as a raw material for the production of polyester fibers [ 90 ]. Nowadays, it is produced via hydrolysis of ethylene oxide, with an annual production of 7 million tons (for 2012) [ 90 ].…”

“…Nowadays, it is produced via hydrolysis of ethylene oxide, with an annual production of 7 million tons (for 2012) [ 90 ]. Such large-scale production means that the supply chains are well developed, which simplifies the adaptation to the role of fuel for current sources [ 25 , 90 , 162 ].…”