Bio-inspired design: Bulk iron-nickel sulfide allows for efficient solvent-dependent CO 2 reduction

Piontek, S. and Junge Puring, K. and Siegmund, D. and Smialkowski, M. and Sinev, I. and Tetzlaff, D. and Roldan Cuenya, B. and Apfel, U.-P.

Volume: 10 Pages: 1075-1081
DOI: 10.1039/c8sc03555e
Published: 2019

The electrocatalytic reduction of carbon dioxide (CO 2 RR) to valuable bulk chemicals is set to become a vital factor in the prevention of environmental pollution and the selective storage of sustainable energy. Inspired by structural analogues to the active site of the enzyme CODH Ni , we envisioned that bulk Fe/Ni sulfides would enable the efficient reduction of CO 2 . By careful adjustment of the process conditions, we demonstrate that pentlandite (Fe 4.5 Ni 4.5 S 8 ) electrodes, in addition to HER, also support the CO 2 RR reaching a peak faradaic efficiency of 87% and 13% for the formation of CO and methane, respectively at 3 mA cm -2 . The choice of solvent, the presence of water/protons and CO 2 solubility are identified as key-properties to adjust the balance between HER and CO 2 RR in favour of the latter. Such experiments can thus serve as model reactions to elucidate a potential catalyst within gas diffusion electrodes. © 2019 The Royal Society of Chemistry.

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