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[求助]
幫忙翻譯化學文獻中的英文 英譯漢4
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4. Synthesis. All chemicals used for the synthesis can be purchased commercially and have the highest possible purities (≥99.99%). One-half of a gram of K2Cr2O7 was placed in an alumina boat. This boat was then placed in a stainless steel tube with airtight, stainless steel end-caps that have welded valves and connections to input and output gas lines. All gases were purified to remove trace amounts of oxygen or water using pellet copper, nickel, palladium, and platinum on zeolite supports. The stainless steel tube was then placed in a split tube furnace, and the appropriate connections to the gas sources were made. An argon gas flow through the tube was used for 15 min to expel the air remaining in the tube before establishing the flow of ammonia gas (Anhydrous, Airgas) through the tube. The sample was then heated in the tube to 700 °C at 150 °C/h. After 8h elapsed at 700 °C, the furnace power was turned off and the product was cooled to room temperature in ∼4 h under an ammonia gas flow. Before the stainless steel tube was taken out of the split tube furnace, an argon gas flow through the tube was used to expel the ammonia gas remaining in the tube. After the stainless steel tube was taken out, it was left on a lab bench for 24 h with one valve open so that the ammonolysis product could be exposed to air slowly. The CrN product was washed three times using deionized (DI) water, then dried in a glass desiccator under vacuum for 24h. Pt nanoparticles supported on CrN and Vulcan XC-72 carbon were prepared by a polyol process with ethylene glycol (EG) as a reducing agent. 36 The total Pt loading on each support was 20 wt %. An appropriate amount of H2PtCl6 (99.995%, Sigma-Aldrich) and 50mg of mesoporous CrN (or C) were suspended in 50 mL of ethylene glycol solution. Next, the mixture was heated at 140 °C for 3 h. Subsequently, the suspension was fi ltered and washed with deionized water, and then dried at 80 °C for 6 h to obtain the Pt/CrN catalysts (or Pt/C). |
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