Enhancing the CO<sub>2</sub> Electroreduction of Fe/Ni‐Pentlandite Catalysts by S/Se Exchange
Kevinjeorjios Pellumbi, Mathias Smialkowski, Daniel Siegmund, Ulf‐Peter Apfel
Abstract
Abstract The electrochemical reduction of CO 2 is an attractive strategy towards the mitigation of environmental pollution and production of bulk chemicals as well as fuels by renewables. The bimetallic sulfide Fe 4.5 Ni 4.5 S 8 (pentlandite) was recently reported as a cheap and robust catalyst for electrochemical water splitting, as well as for CO 2 reduction with a solvent‐dependent product selectivity. Inspired by numerous reports on monometallic sulfoselenides and selenides revealing higher catalytic activity for the CO 2 reduction reaction (CO 2 RR) than their sulfide counterparts, the authors investigated the influence of stepwise S/Se exchange in seleno‐pentlandites Fe 4.5 Ni 4.5 S 8‐Y Se Y (Y=1–5) and their ability to act as CO 2 reducing catalysts. It is demonstrated that the incorporation of higher equivalents of selenium favors the CO 2 RR with Fe 4.5 Ni 4.5 S 4 Se 4 revealing the highest activity for CO formation. Under galvanostatic conditions in acetonitrile, Fe 4.5 Ni 4.5 S 4 Se 4 generates CO with a Faradaic Efficiency close to 100 % at applied current densities of −50 mA cm −2 and −100 mA cm −2 . This work offers insight into the tunability of the pentlandite based electrocatalysts for the CO 2 reduction reaction.