A binder-free thin film anode composed of Co2+-intercalated buserite grown on carbon cloth

Hydrogen is one of the most promising energy carrier as it does not discharge carbon dioxide to the atmosphere. There are several techniques for mass production of hydrogen such as steam methane reforming, thermal cracking, electrolysis and photolysis, coal biomass gasification and pyrolysis. Electrolysis entails splitting water into oxygen and hydrogen where the protons collect at the cathode thereby hydrogen gas is accumulated. Of late, this electrochemical process has attracted the interest of scientific community owing to the fact that the entire process is clean.

Unfortunately, the very sluggish kinetics of the oxygen evolution reaction at the anode demands significant energy input, thereby limiting the overall efficiency of water splitting. To this note the development of an efficient catalyst has become a critical issue. Just the other day, researchers discovered that the introduction of nickel/cobalt ions into the interlayer space of layered manganese dioxide remarkably improved its oxygen evolution reaction activity. Unfortunately, fabricating such a metal oxide catalyst on a flat 2D substrate limits the loading amount of the catalyst per unit geometric area of the electrode, thereby yielding a low current density.

Researchers led by Professor Masaharu Nakayama at Yamaguchi University in Japan developed an efficient and simple strategy that could be applied in the fabrication of a catalytic anode composed of a thin film of cobalt ions-buserite grown on a carbon cloth, which possesses high geometric performance and mass activity for oxygen evolution reaction. They hoped to be the pioneers in utilizing the layered manganese oxide (buserite) in the oxygen evolution reaction. Their work is presently published in the research journal, Electrochemistry Communications.

The research team commenced the experimental procedure by obtaining a carbon cloth consisting of woven bundles of carbon microfibers. The carbon cloth was refluxed in acetone for a specific period, washed in ethanol and deionized in water so as to obtain a hydrophilic surface. The researchers then utilized the treated carbon cloth as a working electrode for the oxygen evolution reaction measurements. Electrodeposition was then carried out. Eventually, x-ray diffraction tests were recorded.

The authors observed that the fabricated anode was capable of producing a current density of 10 mA cm⁻² at a small η of 377 mV with a Tafel slope of 48 mV dec⁻¹. The research team also noted that the mass activity was apparently larger than that of the counterpart synthesized chemically, reflecting a decrease in dead volume of the catalyst as a result of electrodeposition and the use of carbon cloth substrate.

The Masaharu Nakayama and colleagues study has presented the fabrication of a highly efficient and stable binder-free anode consisting of cobalt ion intercalated-buserite film as an oxygen evolution reaction catalyst. It has been seen that the carbon cloth- and fluorine-doped tin oxide -supported cobalt ion intercalated-buserite have shown stable responses with small overpotentials, without a steep increase at least within 100 h, which are totally different from that of potassium ion intercalated-birnessite.