4results about How to "Improve photon quantum efficiency" patented technology

The invention belongs to the crossing field of a radioactive wastewater treatment technology and a nano environmental catalytic material, and particularly relates to a photocatalytic material based on an eggshell structure biological source carbon dot / ZnCdS heterojunction and application of the photocatalytic material in uranium extraction. According to the material, biological source carbon dots derived from orange peel are used as a shell layer and wrap the surface of polyhedral ZnCdS to form an eggshell structure heterojunction. The preparation method comprises the following steps: performing pyrolysis and hydrothermal treatment on orange peel to prepare carbon dots; the preparation method comprises the following steps: etching a ZIF-8 precursor through tannic acid, and carrying out vulcanization, cadmium doping and hydrothermal reaction to obtain ZnCdS; and finally, compounding the carbon dots with ZnCdS in ethanol. The eggshell structure effectively promotes the separation of photon-generated carriers and enhances the stability of ZnCdS. In an experiment of photocatalytic reduction of uranyl ions, the uranium removal rate of the material reaches 97.6%, and is remarkably improved compared with 72.3% of pure ZnCdS. The material is low in cost, environment-friendly and suitable for radioactive wastewater treatment and uranium extraction from seawater.

The application relates to the technical field of photocatalytic material preparation, and discloses a preparation method of calcium hydroxystannate material based on morphology reconstruction to enhance intrinsic light absorption, which comprises the following steps: firstly, a regular polyhedral calcium hydroxystannate precursor powder is prepared by adopting a liquid phase precipitation method; subsequently, deionized water and anhydrous ethanol are mixed to construct a solvent cage medium, and a low-concentration etching working solution is prepared by adding an organic weak acid; the precursor is added into the working solution for constant-speed stirring, morphology reconstruction is carried out on the crystal surface by using the solvent cage shielding effect and acid etching effect, and solid-liquid separation is carried out immediately after the reaction is completed; the obtained precipitate is washed and dried to obtain the calcium hydroxystannate material with a surface micro-rough structure. Through a mild and limited etching process, a defect layer rich in oxygen vacancies is constructed in situ on the crystal surface, the micro-morphology is reconstructed into an octagonal shape, the band gap width is effectively reduced, the light absorption edge is red-shifted, carrier recombination is inhibited, and therefore the photocatalytic mineralization performance of the material under visible light is improved.

This invention provides a visible light responsive titanium dioxide photocatalyst, its preparation method, and its application. The photocatalyst has a core-shell structure or a heterojunction interface structure and includes the following components: matrix material: modified nano-titanium dioxide; modifying material: chiral carbon quantum dots; the chiral carbon quantum dots are grown in situ or grafted onto the surface of the matrix material through Ti-O-C chemical bonds or strong electrostatic interactions; the photocatalyst utilizes the spin filtering effect generated by the CISS effect of the chiral carbon quantum dots, so that the photogenerated electrons injected into the matrix and the remaining holes are in a spin-forbidden state, thereby inhibiting recombination; this invention uses physical laws rather than simple energy level matching to inhibit recombination, significantly improving the quantum efficiency; the long-lived electrons and holes can continuously generate active free radicals, effectively overcoming the difficult-to-degrade VOCs containing benzene ring structures such as toluene, and reducing the generation of intermediate products; the raw materials used are all inexpensive chemical products, free from heavy metal pollution, and suitable for large-scale industrial production.

The invention relates to the technical field of photocatalytic materials, and provides a carboxyl small molecule compound modified MPM material, a preparation method and application, and the preparation method comprises the step of carrying out amidation reaction on an amino-containing MPM material and a carboxyl small molecule compound to form the carboxyl small molecule compound modified MPM material. Compared with the prior art, according to the preparation method of the carboxyl small molecule compound modified MPM material, the MPM material containing amino and the carboxyl small molecule compound are subjected to the amidation reaction for bridging connection, the modified MPM material with the enhanced photocatalytic performance is formed, and the carboxyl small molecule compound can be used as molecular glue. The framework connectivity and the structural order degree are enhanced by combining the synergistic effect of coordination bonds and hydrogen bonds of metal-carboxylic acid of the MPM material, the separation and migration of photo-generated charges are effectively promoted, and the rapid compounding of photo-generated electron-hole pairs is successfully inhibited, so that the light quantum efficiency is improved, and the photocatalytic performance is remarkably improved.