Al-H2O反应中催化剂对Al(OH)3形貌演化的作用机理(英文)

研究不同催化剂在铝-水(Al-H₂O)反应中对Al(OH)₃晶体形貌及其生长机理的作用。采用NaOH、KOH、四甲基胍(TMG)和四甲基氢氧化铵(TMAH)作为催化剂进行反应,原位观察产物的演化过程。结果表明,反应120 min后得到的产物分别具有六棱柱形、六棱长柱状、长棒状和不规则棒状。在NaOH和KOH体系中,产物为三水铝石,三水铝石在NaOH体系中主要沿(110)、(001)和(100)晶面生长,而在KOH体系中主要沿(100)、(102)和(110)晶面生长。在TMG和TMAH体系中,产物是拜耳石,拜耳石在这两个体系中均沿(110)、(111)和(001)晶面生长。其中,三水铝石的Al—O键较多,有利于柱状晶体的形成。     

Preparation of anodic films on 2024 aluminum alloy in boric acid-containing mixed electrolyte

The anodizing oxidation process on 2024 aluminum alloy was researched in the mixed electrolyte with the composition of 30 g/L boric acid, 2 g/L sulfosalicylic acid and 8 g/L phosphate. The results reveal that the pre-treatment and the composition of the mixed electrolyte have influence on the properties of the films and the anodizing oxidation process. Under the condition of controlled potential, the anodizing oxidation current-time response curve displays “saddle” shape. First, the current density reaches a peak value of 8-20 A/dm^2 and then decreases rapidly, finally maintains at 1-2 A/dm^2. The film prepared in the mixed electrolyte is of porous-type with 20 nm in pore size and 500 μm^-2 in porosity. Compared with the conventional anodic film obtained in sulfuric acid, the pore wall of the porous layer prepared in this work is not continuous, which seems to be deposited by small spherical grains. This porous structure of the anodic film may result from the characteristics of the mixed electrolyte and the special anodizing oxidation process. The surface analysis displays that the anodic film is amorphous and composed of O, Al, C, P, S, Si and no copper element is detected.     

Preparation of Ni nanoparticles plating by electrodeposition using reverse microemulsion as template

Ni nanoparticles plating was prepared in reverse microemulsion. The deposition was carried out through the Brownian motion of water pools in the reverse microemulsion and the adsorption of water pools on the electrode surface. Effects of electrolytic parameters on the size of Ni particles were studied. The performances of hydrogen evolution and hydrogen storage of the Ni nanoparticles plating electrode were also investigated. The results indicate that the size of Ni nanoparticles decreases with the increase...     

铝表面精细阳极氧化研究进展

随着纳米科学技术的发展,铝阳极氧化由传统的普通氧化进入到精细氧化.精细氧化技术经历了两步阳极氧化法、快速阳极氧化法和循环或多步氧化法3个阶段.铝表面精细阳极氧化技术有望在铝及铝合金的功能化应用方面得到进一步的发展.     

钼/钒-白云石双功能催化剂催化甘油脱水-氢转移制烯丙醇

采用浸渍法制备同时具有碱性位点和氧化还原位点的MoO/VO-CD-T(CD为煅烧白云石，T为煅烧温度)双功能催化剂。结果表明，催化剂表面钼/钒氧化物主要由MoO₃和V₂O₅组成；煅烧白云石与钼、钒氧化物之间形成不同的物相，可进一步调节催化剂稳定性和氧化还原性能。在空气气氛下CD-500负载的V₂O₅催化剂更有利于烯丙醇形成，主要是因为空气中氧气的存在会抑制高价态钒的还原；而CD-500负载钼的氧化物对烯丙醇的活性较低，因为Mo⁶⁺的还原能力弱。以质量分数为20%的甘油溶液为原料，在反应温度为320℃的条件下，2%VO-CD-500催化剂(2%为VO的质量分数)催化性能相对最佳，甘油转化率为52.4%，烯丙醇选择性为37.4%。