The team of Wang Wenzhong, a researcher at Shanghai Institute of Silicate, Chinese Academy of Sciences, has made new progress in the research on photocatalytic conversion of methane. The related research results were recently published in Nature-Communication, and applied for an invention patent in China.
the selective activation and directional conversion of methane is a worldwide problem, which is known as the "holy grail" in the field of catalysis and even chemistry. The conversion of methane usually adopts indirect method: methane is converted into synthesis gas by steam reforming at high temperature, and then multi-carbon basic chemicals are obtained by Fischer-Tropsch synthesis; Or make methanol from synthesis gas, and then produce other chemicals. The conversion route is long, energy consumption is high, and a large amount of carbon dioxide is emitted, which not only brings environmental load, but also the utilization rate of total carbon is less than half. Therefore, scientists have been exploring the method of direct conversion and utilization of methane.
The researchers introduced that photocatalytic direct conversion can break the shackles of traditional thermodynamic equilibrium and make methane conversion at low temperature and normal pressure. They designed and prepared copper-modified carbon nitride materials to realize the photocatalytic direct conversion of methane to ethanol, and studied the mechanism of this process in depth.
from the perspectives of the generation of reactive oxygen species and the adsorption and activation of methane, the researchers modified the ordered cavities of carbon nitride materials by copper, which not only realized the in-situ generation of hydroxyl radicals, but also promoted the activation of methane C-H bonds and the stability of highly active intermediate species. The material shows excellent photocatalytic methane conversion performance. In-depth research shows that besides the free radical mechanism, there is a synergistic effect between the copper species in the material and the adjacent carbon atoms, which makes the conversion process follow the path of methane-methanol-ethanol.
This study puts forward a new strategy of direct conversion of methane to liquid fuel under mild conditions, which is helpful to deepen the understanding of the formation mechanism of multi-carbon products.