STRATCAT-CO2 · Surface functionalization with thiols: a novel strategy in catalyst design for the efficient reduction of CO2 to C2 products

Surface functionalization with thiols: a novel strategy in catalyst design for the efficient reduction of CO2 to C2 products

Since its birth more than 250 years ago, the chemical industry has become a key sector in the European economy: today, it generates 1.1% of the European Union’s gross domestic product and ca. 1.15 million direct jobs. It is also the EU’s largest industrial energy consumer and third largest industrial emitter of carbon dioxide. In its climate action roadmap, the European Commission targets an 80% reduction of greenhouse gas emissions by 2050 (compared to 1990 levels) as well as a nearly exclusive use of low-carbon energy sources in power generation. The chemical industry is a crucial stakeholder for achieving these goals by (1) replacing fossil feedstocks, (2) electrifying its production processes to make use of renewable energy, and (2) providing large-scale solutions for energy storage from intermittent renewable sources. In this context, the Climate Action roadmap sets the stage for nothing less than a fundamental transformation of the chemical industry. Combining the electrochemical CO2 reduction reaction (eCO2RR) with increasingly affordable renewable energy sources provides groundbreaking opportunities to use CO2 as a medium for energy storage and as a raw material in chemical production. In particular, ethanol and ethylene are high-value products that can be obtained from the eCO2RR, with wide applications as a fuel and as a building block in the chemical industry, respectively. Practical implementation requires the development of CO2 reduction catalysts with high selectivity toward the target products at low overpotentials. Despite recent progress in achieving these requirements for the simplest eCO2RR products (i.e., carbon monoxide and formate), reaching high performance in the reduction of CO2 to ethylene and ethanol remains a major challenge. Moving the field forward to unlock the vast potential of the eCO2RR requires investigating new concepts in catalyst design while gaining fundamental insights into their mechanistic effect. In this context, the STRAT-CO2 project sought to investigate a novel strategy for the design of eCO2RR catalysts—based on surface functionalization with organic ligands—targeting the reduction of CO2 to multicarbon products with high efficiency. In particular, the project the following two objectives: 1. To gain a fundamental understanding of how electronic and geometric effects from adsorbed thiols modulate selectivity and activity toward C2 products over surface-functionalized electrodes. 2. Building on this understanding, to develop a catalyst that shows high efficiency in reducing CO2 to ethylene or ethanol at a practically relevant current density of 200 mA cm-2.

Data: CORDIS, © European Union