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Active Sulfur Sites in Semimetallic Titanium Disulfide Enable CO2 Electroreduction

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journal contribution
posted on 27.11.2019, 19:45 authored by Abdalaziz Aljabour, Halime Coskun, Xueli Zheng, Md Golam Kibria, Moritz Strobel, Sabine Hild, Matthias Kehrer, David Stifter, Edward H. Sargent, Philipp Stadler
Electrocatalytic CO2-to-CO conversion represents one pathway to upgrade CO2 to a feedstock for both fuels and chemicals (CO, deployed in ensuing Fischer–Tropsch or bioupgrading). It necessitates selective and energy-efficient electrocatalystsa requirement met today only using noble metals such as gold and silver. Here, we show that the two-dimensional sulfur planes in semimetallic titanium disulfide (TiS2) provide an earth-abundant alternative. In situ Fourier transform infrared mechanistic studies reveal that CO2 binds to conductive disulfide planes as intermediate monothiocarbonate. The sulfur–CO2 intermediate state steers the reduction kinetics toward mainly CO. Using TiS2 thin films, we reach cathodic energy efficiencies up to 64% at 5 mA cm2. We conclude with directions for the further synthesis and study of semimetallic disulfides developing CO-selective electrocatalysts.

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