A research team led by Prof. Dong Liu from Suzhou Institute for Advanced Research, University of Science and Technology of China, have successfully construct Cu and Si co-doped ultrathin TiO2 nanosheets. As confirmed by comprehensive characterizations, Cu and Si co-doping can rationally tailor the electronic structure of TiO2 to maneuver reactive oxygen species for effective photocatalytic methane conversion. The study was published in Nanoscale Horizons.

     Natural gas has received widespread attention as an important clean, low-carbon energy source and chemical raw material. However, the inert C–H bond and highly symmetrical structure of methane molecule make it substantially challenging to transform methane into target products. Conventional methane activation is a severe energy-intensive process with carbon emissions. It requires critical conditions (i.e., high temperature and pressure) to activate the C–H bond combined with sophisticated post-processes. Thus, it is urgent to develop efficient and selective approaches for the transformation of methane into value-added compounds under moderate conditions.

The researchers successfully fabricated Cu and Si co-doped ultrathin TiO2 nanosheets for efficient photocatalytic methane conversion at room temperature and ambient pressure. As demonstrated by comprehensive characterizations, the presence of Cu and Si could rationally regulate the electronic structure of TiO2 nanosheets and modulate the reactive oxygen species for the activation of C–H bonds, accompanied with the presence of oxygen vacancies and Ti3+ species in the TiO2 matrix. 

The idea of modulating the reactive oxygen species by co-doping to improve the selectivity of photocatalytic methane conversion C2+ products can provide a reference for the design of efficient methane selective conversion catalysts to help achieve the goal of carbon peaking and carbon neutralization.

Paper link: https://doi.org/10.1039/D2NH00457G