3results about How to "Change the microstructure" patented technology

This invention discloses a method for preparing a ruthenium-doped nickel-iron-based heterostructure catalyst and its application. The preparation method includes the following steps: dissolving oxalic acid and an iron salt in water to obtain an iron precursor solution; placing nickel foam in the iron precursor solution for a hydrothermal reaction to form a nickel-iron-based heterostructure on the nickel foam; and placing the nickel foam with the nickel-iron-based heterostructure in a ruthenium salt solution for an impregnation reaction to obtain the ruthenium-doped nickel-iron-based heterostructure catalyst, wherein ruthenium is doped within the crystal lattice of the nickel-iron-based heterostructure. The ruthenium-doped nickel-iron-based heterostructure catalyst prepared by this invention can be applied to the electrocatalytic water splitting reaction and exhibits good electrocatalytic total water splitting performance.

The invention relates to sprayed concrete and a preparation method thereof, and relates to the technical field of concrete.The sprayed concrete is prepared from, by weight, 365-410 parts of cement, 790-830 parts of fine aggregate, 710-760 parts of coarse aggregate, 70-100 parts of fly ash, 75-95 parts of modified yellow phosphorus slag, 12-16 parts of accelerator, 4.5-7 parts of water reducer, 3-6.5 parts of natural plant admixture and 155-175 parts of water; the natural plant additive is prepared from beet root tubers and gelidium amansii in a weight ratio of (1-2): (5-9). On the basis of an existing shotcrete batching system, the natural plant admixture and the modified yellow phosphorus slag are introduced, all the components have a synergistic effect, the construction requirements for the initial strength and the later strength of the shotcrete are met, the rebound rate of the shotcrete is remarkably reduced, and the shotcrete has a good application prospect. The method can be widely applied to construction of various supporting projects such as tunnels and roadways.

The invention provides a preparation method of a large-area ultrathin perovskite single crystal. The preparation method comprises the following steps: S1, obtaining a perovskite seed crystal; s2, putting the perovskite seed crystal in the step S1 into a first solvent, and heating to carry out heat treatment on the perovskite seed crystal to change a surface microstructure; s3, placing the treated perovskite seed crystal in a glass container, sequentially adding a second solvent and a perovskite precursor growth solution, and placing the glass container on a heating stage to obtain a perovskite single crystal with the thickness of 1-2cm; s4, fixing the perovskite single crystal on a glass sheet by using paraffin, cutting off seed crystals in the perovskite single crystal by using a blade, and thinning the perovskite single crystal to obtain a large-area ultrathin perovskite single crystal wafer; wherein the second solvent in the step S3 is immiscible with the perovskite precursor growth solution, and the density of the second solvent is smaller than that of the perovskite precursor growth solution. The method has the advantages of inhibiting the growth of the crystal in the vertical direction, reducing the carrier recombination rate and reducing the crack and breakage probability.