Carbon dioxide (CO2) is a major greenhouse gas that can cause global warming. An ideal strategy to mitigate the atmospheric CO2 concentration is to recycle CO2 back into useful chemicals or low-carbon fuels. CO2 reforming of methane (CH4) or dry reforming of methane (DRM) is an attractive approach to convert CO2 into syngas (CO and H2). However, the widely studied thermal-driven DRM process requires the use of fossil fuels to provide thermal energy, leading to the re-emissions of greenhouse gases. On the other hand, room-temperature photocatalytic DRM using semiconductor photocatalysts has been demonstrated; however, the efficiency of low-temperature photocatalytic DRM is extremely low. Here, we report a novel approach of integrating photocatalysis and thermocatalysis in one system to drive DRM at a high temperature, namely photothermal catalytic DRM (PTC-DRM), by efficiently utilizing the concentrated solar to supply both high-energy photons (UV and near UV) to drive photocatalysis and thermal energy (visible and IR) to drive thermocatalysis. A unique catalyst, Pt supported Si-modified CeO2, was designed for this novel PTC-DRM reaction by integrating photocatalytic and thermocatalytic effects, where Pt was the thermocatalytic DRM catalyst and co-catalyst for photocatalysis, CeO2 was the DRM support and semiconductor photocatalyst, and Si was the promoter and stabilizer. Under 30 equivalent suns irradiation at 600 °C in 30 h, the production rates of H2 and CO reached a high level at 90 and 154 mmol g−1 h−1, respectively, which were 5 and 2 times higher than those obtained in the dark at the same temperature. More importantly, we found that light irradiation could significantly enhance DRM stability without decay in a 20-h test, while thermally driven DRM deactivated drastically. Mechanistic studies using in situ diffuse reflectance infrared Fourier transform spectroscopy demonstrated that photocatalysis decreased the reaction temperature for reactants activation compared to that required by thermocatalysis alone. Taking advantages of the synergy of photocatalytic and thermocatalytic effects, PTC-DRM represents a new direction in low-carbon fuel production from sunlight.

High-temperature photothermal catalytic CO2 reforming of methane on Pt/CeO2-based catalysts using concentrated solar

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.