With the over-exploitation of resources and the aggravation of environmental pollution, the problem of energy and environment has become the main concern in today's world. A variety of new technologies and ideas are emerging to try to solve these problems in a variety of ways. Photocatalysis USES light to excite the semiconductor photocatalytic material, so that photogenerated electrons and holes are formed in the conduction band and valence band of the semiconductor respectively. After the photogenerated electrons and holes are transported to specific areas on the surface of the catalyst, they can participate in the photodecomposition of water or the degradation of organic compounds. Photocatalysis can directly split water into hydrogen and oxygen to produce clean energy, or oxidize and decompose organic matter to produce carbon dioxide and water. Therefore, compared with existing technologies, photocatalysis has the advantages of no secondary treatment, recyclable reuse, low cost, green and pollution-free. As a green means to solve both energy and environment problems, photocatalysis has been paid more and more attention. The core of semiconductor photocatalysis technology is to prepare photocatalytic materials with high efficiency. The ideal photocatalytic materials should have such characteristics as wide light absorption range, high light energy utilization rate, good stability, environmental friendliness and low cost. TiO_2 is the most widely studied and applied semiconductor photocatalytic material.
. Many researches at home and abroad show that photocatalytic technology can decompose a variety of pollutants in air and water. Solar photodecomposition of water technology is expected to obtain cheap hydrogen, the ideal clean energy. Photocatalytic materials have also achieved initial success in air purification, self-cleaning, superhydrophilic and other aspects, and the application market in environmental protection is gradually forming. China's energy structure is facing the dual pressure of economic development and environmental protection. At present, the research on photocatalytic materials is very extensive. Among them, semiconductor TiO2 is the earliest and currently recognized photocatalytic material with excellent performance. TiO2 has been widely studied and actually used due to its many advantages, such as stable chemical properties, strong ultraviolet absorption ability, high quantum efficiency and catalytic efficiency, non-toxic and odorless, abundant sources and low price.
