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

Marta Wala,Wojciech Simka

doi:10.3390/molecules26082144

Marta Wala, Wojciech Simka

Open Access

https://doi.org/10.3390/molecules26082144

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Abstract

The growing climate crisis inspires one of the greatest challenges of the 21st century—developing novel power sources. One of the concepts that offer clean, non-fossil electricity production is fuel cells, especially when the role of fuel is played by simple organic molecules, such as low molecular weight alcohols. The greatest drawback of this technology is the lack of electrocatalytic materials that would enhance reaction kinetics and good stability under process conditions. Currently, electrodes for direct alcohol fuel cells (DAFCs) are mainly based on platinum, which not only provides a poor reaction rate but also readily deactivates because of poisoning by reaction products. Because of these disadvantages, many researchers have focused on developing novel electrode materials with electrocatalytic properties towards the oxidation of simple alcohols, such as methanol, ethanol, ethylene glycol or propanol. This paper presents the development of electrode materials and addresses future challenges that still need to be overcome before direct alcohol fuel cells can be commercialized.

Highlights

With the growing world population and technological development, energy demands are constantly increasing; developing more sustainable energy sources is one of the greatest technical challenges of the 21st century
For more advanced engine technologies, such as internal combustion engines, methanol and ethanol have been considered as fuel since their invention and have played the role of the fuel blends that have increased the octane number when added to the gasoline [3]
Catalyst stability can decrease as a result of the presence of ruthenium oxide because it can over-provide the catalyst with oxygen species, which leads to surface poisoning with Au2O3–gold(III) oxide, which shows no catalytic properties towards EGOR and blocks bulk ethylene glycol molecules from adsorption on the electrode surface [86]

Summary

Introduction

With the growing world population and technological development, energy demands are constantly increasing; developing more sustainable energy sources is one of the greatest technical challenges of the 21st century. The use of lightweight alcohols as a fuel goes back to the 19th century, as it was the fuel recommended by Otto when he has developed the spark-ignition engine [1] In such an engine, methanol has lower air consumption (14.55 kg/kg vs 6.5 kg/kg) and a higher octane number (97.7 vs 108.7) than conventional gasoline [2]. The simple burning of these compounds for conventional power generation could lead to large energy losses., so gathering energy directly from a controlled reaction would be much more beneficial This idea is the foundational concept of fuel cells (Figure 1). The main problem is related to the lack of electrode materials, mainly for anodes, which should be durable in reaction conditions and inexpensive and show catalytic properties towards fuel oxidation The development of such materials is a very complicated and time-consuming process that requires extensive research. Comparison of discussed alcohols that shows advantages and disadvantages of each alcohol as a fuel

Structure of Anodic Material

Ethanol Oxidation

Ethylene Glycol Oxidation

Propanols

Conclusions