7 results about "Chromium doping" patented technology

The invention provides a solid laser with a periodic chromium-doped structure gain medium. The solid laser comprises a pumping source, a pumping coupling device, a laser resonant cavity input end cavity mirror, a laser gain medium and a laser resonant cavity output coupling mirror which are arranged in sequence, the pumping source is used for emitting pumping light with the wavelength capable of being absorbed by the laser gain medium; the pumping coupling device is used for collimating and focusing the pumping light emitted by the pumping source into the laser gain medium; the laser resonant cavity input end cavity mirror is used for passing through the pump light and reflecting the laser emitted by the laser gain medium; the laser gain medium is a blocky solid gain medium with a chromium-doped structure, and the chromium-doped concentration of the laser gain medium changes periodically; and the laser resonant cavity output coupling mirror is used for partially transmitting the laser emitted by the laser gain medium. The structure with the doping concentration changing periodically in the laser gain medium can effectively relieve the heat effect generated by the gain medium under the excitation of the pump light, so as to realize the stable output of the laser.

This invention discloses a trivalent chromium-doped magnesium calcium aluminate deep red phosphor and its preparation method. The phosphor is trivalent chromium ion-doped magnesium calcium aluminate with the chemical formula CaMg2Al. 16‑x O 27 :xCr 3+ The elemental molar ratio is Ca:Mg:Al:O:Cr = 1:2:(16-x):27:x, where 0.01≤x≤0.10. This invention also discloses a method for preparing this phosphor. The deep red luminescent phosphor of this invention exhibits absorption in the 300-650 nm region and its emission spectrum is located in the 600-880 nm region. Its emission color is in the deep red to near-infrared range, which matches the deep red absorption spectrum of plant photosynthesis. This phosphor has potential application prospects in plant LED lighting.

The invention discloses a chromium-doped bismuth nanoflower electrocatalyst and a preparation method and application thereof, and belongs to the technical field of nano material preparation, and the method comprises the following steps: respectively dissolving a bismuth source and a chromium source in deionized water, mixing, stirring, heating, reacting, filtering, washing, drying, dispersing in a solvent, adding a Nafion solution, fully mixing, and drying to obtain the chromium-doped bismuth nanoflower electrocatalyst. Catalyst precursor slurry is obtained; spraying the catalyst precursor slurry on a material containing a gas diffusion layer under a heating condition, and drying to obtain a working electrode; and assembling a gas diffusion electrolytic tank by taking the working electrode as a cathode, and preparing the chromium-doped bismuth nanoflower electrocatalyst through an electrochemical reduction reaction. The preparation method is simple and efficient, chromium doping can optimize a local electronic structure and promote water dissociation to efficiently provide protons, and finally the catalytic activity and stability are improved. Industrial production is easy, and the defects that other existing synthesis methods are complex, and planning preparation is difficult are overcome.

The invention belongs to the technical field of battery materials, and particularly relates to a chromium-doped ternary material precursor, a ternary material and a preparation method and application thereof. The invention provides a preparation method of a chromium-doped ternary material precursor. The preparation method comprises the following steps: (1) reacting a nickel-cobalt-manganese solution to prepare an intermediate product; the reaction time is 10 to 30 hours; (2) simultaneously adding a nickel-cobalt-manganese solution and chromium salt into the intermediate product, reacting, adjusting the pH value of a reaction system, and aging to prepare a chromium-doped ternary material precursor; wherein before the pH of the reaction system is adjusted, the pH is less than or equal to 12; the pH value of the reaction system is more than 12 and less than or equal to 14 after being adjusted. The prepared chromium-doped ternary material precursor has a porous structure, is uniform in chromium element doping, low in residual alkali, stable in structure, controllable in morphology and uniform in granularity, and the process is simple and easy to implement.

The application discloses a kind of nitrogen-doped sodium ion battery polyanion positive electrode materials and preparation method thereof, by chromium doping or replacement nitrogen triphosphoric polymeric vanadium trisodium polyanion positive electrode material, citric acid is dissolved with transition metal in deionized water, V source, Cr source, ascorbic acid and transition metal, Na source and P source are added respectively, while the deionized water solution of 12wt% polyvinylpyrrolidone dissolved, urea is added to mixed solution and is magnetically stirred, evaporates by water, drying, grinding, is formed into tablet by mould pressing;With urea grinding and tabletting by mould are together to the test tube and are vacuum sealed, and are placed in muffle furnace and are kept at high temperature, then are taken out and are naturally cooled to room temperature, obtain the positive electrode material.The application does not need to continuously pass in ammonia in preparation process, and reduces the V source consumption, significantly reduces the manufacturing cost is low and manufacturing equipment is simple, improves safety, and is convenient to implement;The cycle of the material prepared is good, and the specific capacity is high.

The application belongs to the technical field of luminescent materials, and provides a blue light excited chromium-doped binary near-infrared luminescent material and a preparation method thereof. 1‑ x Cr x S, wherein 0≤x≤0.15%; the preparation method comprises the following steps: according to the chemical general formula Mg 1‑x Cr x S, the raw materials are weighed according to the molar ratio of Mg:Cr in the raw materials being 1-x:x, x being 0≤x≤0.15%, wherein the raw materials are compounds containing Mg and Cr elements respectively; the weighed raw materials are added into a dispersant and sufficiently ground to obtain a uniform white powder; the ground white powder is pre-fired at 600-700 DEG C for 2-3h, then sulfurization gas is introduced, and the material is fired at 700-800 DEG C in a sulfurization environment for 2-3h, so that the blue light excited chromium-doped binary near-infrared luminescent material is obtained. The material prepared by the application has high luminescent intensity, ideal fluorescent lifetime and is green and pollution-free.

The invention relates to the technical field of catalyst preparation and application, in particular to a molybdenum disulfide catalyst and a preparation method and application thereof.The preparation method comprises the steps that chromium salt, thiourea and ammonium molybdate are dissolved in deionized water, a pretreated conductive substrate is added, and a uniform self-supporting chromium-doped molybdenum disulfide nanosheet array is synthesized through a one-step hydrothermal method. The electronic structure of molybdenum disulfide is regulated and controlled through chromium doping, the catalytic reaction energy barrier is reduced, and the conductivity and the catalytic performance are improved. The prepared chromium-doped molybdenum disulfide ultrafine nanosheet catalyst has good catalytic activity when being used for hydrogen evolution reaction. In a three-electrode alkaline electrolytic cell hydrogen production system, the current density of 10 mA cm <-2 > can be output by only needing the low potential of 0.142 V, and the target of efficient and energy-saving hydrogen production is achieved. The method has the advantages of simple and controllable preparation process, low preparation cost, large-scale production and the like, and can be used as an efficient catalyst for water electrolysis hydrogen production reaction.