Photocatalysis provides a route to convert methane into an energy-dense, liquid fuel, such as methanol, using only natural gas, sunlight, water (or oxygen), and the catalyst. In this report, we compare the photocatalytic activity and selectivity for bismuth vanadate (BiVO4) microcrystals with different morphologies to partially oxidize methane to methanol. Bipyramidal BiVO4 microcrystals comprising {102} and {012} surface facets were found to be both more active and more selective for methane to methanol conversion compared to platelet microcrystals that expose {001} facets as their top and bottom surface. The selectivity of the bipyramidal BiVO4 microcrystals for methanol production was over 85% for reaction times between 60 and 120 min with mass activity between 112 and 134 μmol h–1 g–1 during this period. These activities are among the highest reported for photocatalytic methane to methanol conversion using illumination conditions comparable to solar irradiation and without the need for sacrificial reagents. Photochemical deposition of metal salts indicates that photoexcited electrons and holes react selectivity at different facets of the platelet and bipyramidal BiVO4 microcrystals. Combining the photodeposition results with surface energy calculations, we propose that the high selectivity for methanol observed using bipyramidal BiVO4 microcrystals arises due to efficient extraction of photoexcited holes from surfaces that have intermediate reactivity for oxidation.

Inspired by the rapid development of metal-organic-framework-derived materials in various applications, a facile synthetic strategy was developed for fabrication of 3D hierarchical nanoarchitectures. A surface-mounted metal-organic framework membrane was pyrolyzed at a range of temperatures to produce catalysts with excellent trifunctional electrocatalytic efficiencies for the oxygen reduction, hydrogen evolution, and oxygen evolution reactions.

In this study, we summarize a series of typical 2D nanomaterials for photocatalytic CO2conversion. Furthermore, based on the characteristics of 2D materials and the current status of research on photocatalytic CO2reduction, the challenges and opportunities of 2D materials as prospective photocatalysts for CO2reduction will also be discussed.