Photocatalysis has been widely developed and put into practical use in the areas of antifouling and antifogging，research on artificial photosynthesis—the process of extracting hydrogen through photocatalysis—has also been garnering significant attention in recent years as a technology with the potential to contribute to a decarbonized society. Along with the shift to replace fossil fuels with renewable energies such as hydrogen ,another important measure to achieving a decarbonized society is carbon recycling, effectively using CO2 as a resource. In consideration of that viewpoint, I has proposed the following method: first, extract hydrogen through water electrolysis using the electricity produced from highly efficient solar cells. Next, combine the extracted hydrogen with the CO2 emitted from power plants and factories to produce methanol, which can be used as an energy source.