The carrier can provide the catalyst with appropriate shape, size, and mechanical strength to meet the operational requirements of industrial reactors; The carrier can disperse the active components on the surface of the carrier, obtain a higher specific surface area, and improve the catalytic efficiency per unit mass of active components. If platinum is loaded onto activated carbon. If molecular sieves are used as carriers, platinum can achieve a dispersion close to atomic level. The carrier can also prevent the active components from sintering during use, improving the heat resistance of the catalyst. For certain strongly exothermic reactions, the carrier dilutes the active components in the catalyst to meet the requirements of thermal equilibrium; A carrier with good thermal conductivity, such as metal, silicon carbide, etc., helps to remove the heat of reaction and avoid local overheating of the catalyst surface. Carriers can also load certain catalysts originally used in homogeneous reactions onto solid carriers to produce solid catalysts, such as [solid acid catalysts] made by adsorbing phosphoric acid onto diatomaceous earth, and immobilized enzymes made by loading enzymes onto carriers.
The role of TiO2 photocatalyst carrier is mainly reflected in:
(1) Fixing TiO2, preventing loss, easy recycling, and improving the utilization rate of TiO2.
(2) Increase the overall specific surface area of TiO2 photocatalyst.
(3) Improve photocatalytic activity. Because certain carriers can interact with TiO2, it facilitates the separation of E-H+and increases the adsorption of reactants, while achieving carrier regeneration.
(4) Improve the utilization rate of light sources. After TiO2 is made into a thin film, the number of catalyst particles exposed to light on the surface of the chemical agent increases.
(5) Fixing the catalyst with a carrier facilitates the fabrication of various shapes of photocatalytic reactors.
The photocatalyst carrier first requires the ability to improve the organizational structure of the loaded material (such as increasing pores, surface area, etc.). At the same time, since photocatalysts rely on the combination of light and catalyst to exert catalytic effects, only catalysts activated by light have photocatalytic effects. Therefore, a good photocatalyst carrier should have the following characteristics: good transparency; On the premise of not affecting the catalytic activity of TiO2, it has strong binding force with TiO2 particles; Large specific surface area; Has strong adsorption capacity for degraded pollutants; Easy to separate solid and liquid; Beneficial for solid-liquid mass transfer; Chemical inertness, etc.
