4results about How to "Avoid deep oxidation" patented technology

The invention relates to a post-treatment method for a mercury-based II-VI group nanocrystal with a protective layer formed by chemical oxidation, and solves the problems of poor stability and photoelectric property degradation of the mercury-based II-VI group nanocrystal caused by surface oxidation, ligand desorption and environmental sensitivity. An oxide protection layer with the thickness of 1-3 nm is formed on the surface of the nanocrystal, the long-term stability and the photoelectric property of the nanocrystal are improved, and the method comprises the specific steps of centrifugal purification of the nanocrystal, preparation of an oxidizing agent solution, controllable oxidation reaction, functional ligand surface modification and purification treatment. The oxidation layer is ensured to be compact and stable by accurately adjusting the concentration of the oxidant, the reaction temperature and the reaction time. According to the method, oxygen and moisture permeation is effectively blocked, surface defects are reduced, the quantum yield and the photoelectric property are improved, and the method is widely applied to the fields of post-treatment of mercury-based II-VI group nanocrystals and photoelectric devices.

This invention relates to a method for the coupling production of C2 hydrocarbons and benzene from methane via carbon dioxide oxidation, belonging to the field of chemical production technology. Specifically, a mixture of methane and carbon dioxide is passed through a reactor equipped with a catalyst to produce C2 hydrocarbons and benzene, with carbon monoxide and water as byproducts. In this method, the selective production of C2 hydrocarbons and benzene is achieved by changing the type and composition of the catalyst and simultaneously adjusting the reaction conditions. This invention features a short process flow, simple operation, and uses an inexpensive, readily available, and stable catalyst, making it easy to scale up industrially and showing promising prospects for industrial application.

The application discloses a kind of preparation and application of g-C3N4 / VPO photothermal catalytic material, its characteristics are that g-C3N4 nanosheet is assembled with VPO nanosheet using electrostatic assembly strategy, and photothermal catalytic material of general formula g-C3N4 / VPO is obtained.Under photothermal condition, g-C3N4 / VPO is used as photothermal catalyst, and high-efficiency selective oxidation of n-butane is carried out to prepare maleic anhydride at low temperature.Compared with prior art, the application has the advantages of low reaction temperature, high selectivity, mild preparation conditions, large-scale preparation, green reaction, and wide application prospect.

This invention provides a method for preparing the selective oxidation catalyst FeMo@ZSM-22. The method includes: preparing a mixed metal salt solution by dissolving soluble molybdate and soluble iron salt; ultrasonically dispersing ZSM-22 molecular sieve powder in deionized water to obtain a molecular sieve suspension; slowly adding the mixed metal salt solution dropwise to the molecular sieve suspension under rapid stirring, and adding a precipitant to adjust the pH to 2.0-5.0; and obtaining the FeMo@ZSM-22 catalyst after microwave aging, washing, drying, and calcination. This invention incorporates ZSM-22 molecular sieve in situ during the co-precipitation synthesis of the FeMo catalyst, achieving a high degree of synergy between the redox sites (FeMo) and the weakly acidic sites (ZSM-22) at the nanoscale. The resulting catalyst is used for the direct selective oxidation of dimethyl ether to formaldehyde, not only overcoming the seesaw effect between activity and selectivity in traditional pure metal oxide catalysts, but also exhibiting extremely low preparation cost, good long-term anti-coking stability, and promising prospects for large-scale industrial production.