107results about How to "High active specific surface area" patented technology

The invention relates to a method for preparing a graphite-phase carbon nitride (g-C3N4) material. The method includes the steps that a carbon nitride precursor and ammonium salt are evenly mixed, and then calcination is conducted so that the porous g-C3N4 material can be obtained. The ammonium salt is any one of ammonium base salts capable of generating ammonia gas through thermal decomposition or is the combination of at least two of the ammonium base salts. In the preparation process of the g-C3N4 material, the ammonium salt is added into the carbon nitride precursor to be mixed. In the high-temperature calcining process, the ammonium salt is subjected to pyrogenic decomposition to generate gas, a pore-forming effect on the g-C3N4 material is achieved, and the cellular porous g-C3N4 material is obtained. In the preparation process of the g-C3N4 material, template agents are not used, and thus the method is simple, efficient and environmentally friendly; the prepared g-C3N4 material is high in photocatalytic activity and can be used in the pollution control processes such as exhaust gas and wastewater treatment.

The invention discloses a method for preparing a proton-exchange membrane fuel cell oxygen reduction catalyst based on PtNi (111) octahedral single crystal nanoparticles, which mainly solves the problem in the prior art that a conventional single-Pt catalyst or a Pt-based catalyst based on bimetallic spherical core-shell-structured nanoparticles is low in activity and poor in Pt atomic efficiency. Meanwhile, the influence factor and the synthesis optimization condition for morphology-controlled PtNi (111) octahedral single crystal nanoparticles are obtained. According to the technical scheme of the invention, platinum acetylacetonate and nickel acetylacetonate are adopted as metal salt precursors, and N, N-dimethylformamide (DMF) is adopted as a crystal face growth control agent. Through the heating reduction process, morphology-controlled PtNi (111) octahedral single crystal nanoparticles are obtained. The morphology-controlled PtNi (111) octahedral single crystal nanoparticles are subjected to ultrasonic dispersion in n-hexane, and then the well dispersed sol is slowly added onto the conductive carbon black of high specific surface area drop by drop through the residual titration process. Therefore, the electro-catalysis specific activity of the obtained oxygen reduction catalyst is high up to 1.5 A / mg Pt, and is improved by 9-10 times compared with that of conventional commercial Pt / C catalysts.