RESUMEN
Carbon dioxide (CO2) hydrogenation can not only mitigate global warming, but also produce value-added chemicals. Herein, we report a novel three-phase catalytic system with an in situ generated and dynamically updated thin water film covered on the noble-metal-free TiO2-based catalyst for highly efficient CO2 hydrogenation, realizing a four-time enhancement compared with that with the catalyst suspended in water. The water film plays dual roles by directly participating in the reaction and removing the produced oxygenates (mainly formic acid) from the catalyst surface by dissolution. These results demonstrate an effective design for CO2 hydrogenation, which will open a new door to three-phase catalysis.
RESUMEN
The utilization of visible light for direct photocatalytic methane conversion remains a huge challenge. Here, we developed a thermo-photo catalytic process with a visible-light-responsive Pt/WO3 catalyst and realized highly efficient visible-light driven methane conversion for the first time. The conversion efficiency was enhanced by 4.6 and 14.7 times compared to room-temperature photocatalysis and thermal catalysis at 150 °C, respectively. Furthermore, the production of liquid oxygenates (mainly CH3OH) was found to proceed via photocatalysis with high apparent quantum efficiencies of 5.9%, 4.5%, and 1.9% at 350, 420, and 450 nm, respectively, while CO2 evolution was contributed by photoassisted thermal catalysis. Solid isotope evidence further confirmed that CH3OH, HCHO, and CO2 were produced via parallel rather than sequential reactions. These observations provide a valuable guide for designing a visible-light driven system for methane conversion with high efficiency and controllable selectivity.