Electrochemical reduction of CO2: Two‐ or three‐electrode configuration.

Summary: Electrocatalytical conversion of CO2 into various chemicals like hydrocarbons and CO is regarded as a promising approach to mitigate carbon emission and, meanwhile, to provide sustainable energy and value‐added chemicals. Two different reactors are used in this work. One is based upon the two‐electrode configuration powered by a DC power supply or Si solar cell, which is suitable for practical applications. Another is three‐electrode one powered by a potentiostat, which is feasible to study the electrode performance. Polycrystalline Cu electrode is used as the cathode, and hematite is the anode. Performance of CO2 reduction using the two‐ and three‐electrode configurations is studied by measuring electrode potential, cell voltage, current density, Faradaic efficiency, and reduction selectivity of CO2. Cu cathode used here exhibits a low overpotential for CO2 reduction, specifically for the cell with two‐electrode configuration. No obvious difference can be observed between the two types of configurations at a low bias like −0.3 and −0.4 V; while the reactor with two‐electrode configuration exhibits better performance at a high bias like −0.8 V than the one with three‐electrode configuration. Thus, the reactors with two‐electrode configuration are desirable for practical applications, specifically considering solar cells can be used as the power source to provide green and sustainable energy. [ABSTRACT FROM AUTHOR]