Direct Formation of C<sub>3</sub> Oxygenates through Photocatalytic CH<sub>4</sub>–CO Coupling
Muchun Fei, Boqiang Chen, Yasuhiro Sakamoto, Lizhuo Wang, Yu Mu, Jiwei Zhang, James R. Wilkes, Raven Gallenstein, Jun Huang, Junwei Lucas Bao, Wei Li, Dunwei Wang
Abstract
Multicarbon (C n, where n ≥ 2) oxygenates are important industrial precursors that can be synthesized from the coupling of simple and abundant C 1 feedstock such as CH 4 . While C 2 products from this route have been reported, those involving the direct coupling of more than two C 1 precursors are rare. As a proof of concept, here we report the synthesis of acetone (CH 3 COCH 3 ) through the direct coupling of two CH 4 and one CO using a combined photothermocatalytic approach. With TiO 2 as a light absorber and Pd nanoparticle as a cocatalyst, CH 4 activation and subsequent coupling with CO were achieved at 10 bar and 150 °C. A high selectivity of acetone formation among all liquid products (>80%) was measured. Experiments with isotope-labeled precursors confirmed that the product was a result of the direct coupling of CH 4 and CO. The other major liquid product was acetic acid (CH 3 COOH), which was a result of a single coupling between CH 4 and CO. The suitable binding strength between Pd and the reactive intermediates was proposed as a key reason for the high selectivity toward C 3 products.