Heterogeneous Photocatalysis, IX. Zinc Sulfide Catalyzed Photoreduction of Carbon Dioxide

Abstract

Carbon dioxide is catalytically reduced to formate in a suspension of zinc sulfide in water/2,5‐dihydrofuran when irradiated (λ ≥ 290 nm). Turnover rates are in the range of 1.5 monolayers CO 2 /h. No reaction occurs at pH=12, and a very slow one at pH=3.2,5‐Dihydrofuran functions as reducing agent which is oxidized to dehydro dimers. When it is substituted by 2‐propanol, no CO 2 reduction is observed. Semiconductor photocatalysis by a two‐electron transfer from zinc sulfide to adsorbed hydrogen carbonate is assumed as the key step of CO 2 fixation.