Single Unit Cell Bismuth Tungstate Layers Realizing Robust Solar CO₂ Reduction to Methanol.

Liang, Liang; Lei, Fengcai; Gao, Shan; Sun, Yongfu; Jiao, Xingchen; Wu, Ju; Qamar, Shaista; Xie, Yi

Solar CO2 reduction into hydrocarbons helps to solve the global warming and energy crisis. However, conventional semiconductors usually suffer from low photoactivity and poor photostability. Here, atomically-thin oxide-based semiconductors are proposed as excellent platforms to overcome this drawback. As a prototype, single-unit-cell Bi2WO6 layers are first synthesized by virtue of a lamellar Bi-oleate intermediate. The single-unit-cell thickness allows 3-times larger CO2 adsorption capacity and higher photoabsorption than bulk Bi2WO6. Also, the increased conductivity, verified by density functional theory calculations and temperature-dependent resistivities, favors fast carrier transport. The carrier lifetime increased from 14.7 to 83.2 ns, revealed by timeresolved fluorescence spectroscopy, which accounts for the improved electron-hole separation efficacy. As a result, the single-unit-cell Bi2WO6 layers achieve a methanol formation rate of 75 µmolg-1h-1, 125-times higher than that of bulk Bi2WO6. The catalytic activity of the single-unit-cell layers proceeds without deactivation even after 2 days. This work will shed light on designing efficient and robust photoreduction CO2 catalysts.

CARBON dioxide reduction; INTERMEDIATES (Chemistry); BISMUTH compounds; CHEMICAL synthesis; METHANOL; ADSORPTION capacity; FLUORESCENCE spectroscopy

Angewandte Chemie, 2015, Vol 127, Issue 47, p14177

0044-8249

Academic Journal

10.1002/ange.201506966