Selective photocatalytic conversion of methane into carbon monoxide over zinc-heteropolyacid-titania nanocomposites

Xiang Yu,Vincent De Waele,Vitaly Ordomsky,Andrei Y Khodakov,Axel Löfberg

doi:10.1038/s41467-019-08525-2

Abstract

Chemical utilization of vast fossil and renewable feedstocks of methane remains one of the most important challenges of modern chemistry. Herein, we report direct and selective methane photocatalytic oxidation at ambient conditions into carbon monoxide, which is an important chemical intermediate and a platform molecule. The composite catalysts on the basis of zinc, tungstophosphoric acid and titania exhibit exceptional performance in this reaction, high carbon monoxide selectivity and quantum efficiency of 7.1% at 362 nm. In-situ Fourier transform infrared and X-ray photoelectron spectroscopy suggest that the catalytic performance can be attributed to zinc species highly dispersed on tungstophosphoric acid /titania, which undergo reduction and oxidation cycles during the reaction according to the Mars–van Krevelen sequence. The reaction proceeds via intermediate formation of surface methyl carbonates.

Highlights

Chemical utilization of vast fossil and renewable feedstocks of methane remains one of the most important challenges of modern chemistry
A few examples of methane photocatalytic conversion are available in the literature
A limited number of papers[16,17] have addressed combined photothermocatalytic[18] or plasma-enhanced[19] methane dry reforming, which represents an interesting route for production of carbon monoxide and hydrogen

Summary

Introduction

Chemical utilization of vast fossil and renewable feedstocks of methane remains one of the most important challenges of modern chemistry. We report direct and selective methane photocatalytic oxidation at ambient conditions into carbon monoxide, which is an important chemical intermediate and a platform molecule. The composite catalysts on the basis of zinc, tungstophosphoric acid and titania exhibit exceptional performance in this reaction, high carbon monoxide selectivity and quantum efficiency of 7.1% at 362 nm. Carbon monoxide is a very important compound and a building block in chemical industry. It is utilized as a feedstock in the production of chemicals ranging from acetic acid to polycarbonates and polyurethanes. We report direct selective photocatalytic conversion of methane into carbon monoxide under ambient conditions with only marginal CO2 production: ð1Þ ð2Þ

Methods

Results

Conclusion