How to Stop Cathodic Corrosion of Steel Electrodes in Electroorganic Synthesis

Sustainability is a crucial concern in business and industry these days. Many firms acknowledge the demand to find the very best possible climate-neutral options for producing their products and decreasing contaminants. This indicates they are searching for manufacturing alternatives that do not call for using fossil resources. Great potential in this regard is seen in electrosynthesis, a procedure that entails the improvement of chemical substances in an electrolysis cell using electric energy.c

A team of researchers led by Professor Siegfried Waldvogel, spokesperson of the SusInnoScience Top-Level Research Area at Johannes Gutenberg University Mainz (JGU), has shown that: for instance, that it is feasible to utilize this strategy to extract the flavor substance vanillin from wood waste. One especially promising application of electrosynthesis would be its usage for the manufacturing of plastics precursors. Electrosynthesis would be more efficient than the standard techniques, and it would not require fossil sources. Nevertheless, there is a considerable and grossly neglected snag: Throughout electrosynthesis, a process referred to as cathodic corrosion occurs. Waldvogel’s team determined to further explore this concern by first reviewing the literature on the topic. The outcomes of that research study have been released just recently in Chemical Reviews.

The study team examined articles involving cathodic corrosion released over the past 130 years, including some 30 papers that they made. “Our team, as well as a Chinese group, are the only ones with the needed expertise to perform such a literature testimonial,” emphasized Waldvogel.

According to Waldvogel, researchers have been aware of the problem of cathodic corrosion for over 200 years yet have not found a way of preventing it. The oxidation of the anode, the positive electrode, throughout electrolysis, has been extensively examined, many questions about the reduction at the negative electrode, the cathode, remain unanswered. “It is necessary to make use of materials for the electrodes that have a high overpotential when it comes to hydrogen, so because of that, harmful heavy metals, such as lead and also tin, are utilized,” said Waldvogel. “Nevertheless, the cathode progressively liquifies or corrodes, and releases these toxic metals.”. This can cause contamination of the synthesized chemicals, which is, indeed, an unwanted result. “If we were able to stop this corrosion, we would certainly have eliminated one of the major obstacles to the electrification of production procedures,” he continued. The chemist is currently dealing with two projects created to discover a solution to the crisis. The “Strategies to Overcome Contemporary Limitations of Reductive Electrosynthetic Conversions in Aqueous Media” project was initiated in September 2021. The German Research Foundation is financing it (DFG) and the United States National Science Foundation roughly EUR 1 million.

The focus here is on a functional application. Collaborating with a team at Iowa State University, the goal is to create a method of producing precursors for plastics from agricultural waste– as well as these products are to be synthesized at the cathode. “Presuming we succeed, we will in future be able to use waste to make chemical intermediates, causing sustainable value improvement,” mentioned Waldvogel. According to the group at Mainz College, they will certainly be mostly thinking about the numerous ways salts can cover electrodes, while their American counterparts will be focusing on using alloys with which it is hoped that cathodic rust can be prevented.

Ever since early 2021, researchers of the two JGU Top-Level Study Areas, SusInnoScience and M3ODEL, have collaborated on the ECHELON project, for which the Carl Zeiss Structure is giving some EUR 2 million in financing. “The objective is to acquire a better understanding of the underlying theory of the procedures that take place during electrolysis. For this reason, we are combining aspects of the two essential areas of quantum chemistry and also multiscale modeling,” claimed Waldvogel. “Quantum chemistry allows us to estimate the chemical reactions at the cathode, while multiscale modeling enables us to in theory map the activity as well as the focus of the ions in the fluid bordering the cathode,” he ended.

Originally published on Phys.org. Read the original article.

Reference: Tom Wirtanen et al, Cathodic Corrosion of Metal Electrodes—How to Prevent It in Electroorganic Synthesis, Chemical Reviews (2021). DOI: 10.1021/acs.chemrev.1c00148