Phase transformation and photoluminescence properties of nanocrystalline ZrO2 powders prepared via the Pechini-type sol-gel process

Nanocrystalline ZrO2 fine powders were prepared via the Pechini-type sol-gel process followed by annealing from 500 to 1000 degrees C. The obtained ZrO2 samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), and photoluminescence spectra (PL), respectively. The phase transition process from tetragonal (T) to monoclinic (M) was observed for the nanocrystalline ZrO2 powders in the annealing process, accompanied by the change of their photoluminescence properties. The 500 degrees C annealed ZrO2, powder with tetragonal structure shows an intense whitish blue emission (lambda(max) = 425 nm) with a wide range of excitation (230-400 nm). This emission decreased in intensity after being annealed at 600 degrees C (T + M-ZrO2) and disappeared at 700 (T + M-ZrO2), 800 (T + M-ZrO2), and 900 degrees C (M-ZrO2). After further annealing at 1000 degrees C (M-ZrO2), a strong blue-green emission appeared again (lambda(max) = 470 nm).

Preparation of TiO2, CeO2, and ZrO2 hierarchical structures in "one-pot" reactions

In this paper, a novel template of carbon foam is used in building hierarchical structures of TiO2, CeO2, and ZrO2. They had multiscale morphologies, from nanowalls, nanoparticles to layer nanostructures. Oil a hundred-micron scale, the product was a sponge-like material constructed by nanowalls. On a hundred-nanometer scale, the electron microscope images showed that the nanowalls were porous and assembled by polycrystalline nanoparticles. Meanwhile, on one nanometer scale, many nanoparticles exhibited layer nanostructures with about 1.1 run of thickness and spacing. In mechanism section, the process analysis and characterizations suggested that the hierarchical structures were the combined result of two templates in a "one-pot" reaction. The mesoporous nanowalls were derived from carbon foams, while the layer nanostructures were the replicas of graphite sheets. The method has potential utilizations in preparation of various adsorbent and catalyst.

Preparation of CeO2-ZrO2 ceramic fibers by electrospinning

Electrospinning was employed to fabricate polymer-ceramic composite fibers from solutions containing poly(vinyl pyrrolidone) (PVP), Ce(NO3)(3)(.)6H(2)O and ZrOCl2-8H(2)O. Upon firing the composite fibers at 1000 degrees C, Ce(0.67)Zr(0.33)O(2)fibers with diameters ranging from 0.4 to 2 mu m were synthesized. These fibers exhibit strong resistance to sintering. They still have specific surface area around 11.8 m(2)/g after being heated at 1000 degrees C for 6 h.

贵金属改性的Cu/ZrO2基合成甲醇催化剂及其制备方法和应用

一种贵金属改性的Ｃｕ／ＺｒＯ↓［２］基合成甲醇催化剂重量组成为Ｃｕ：９－２４％，Ｚｒ７５－９０％，Ｐｄ或Ａｇ０．１－１．０％。用硝酸铜和氧氯化锆的混合溶液，在６０－９０℃下与碳酸钠溶液搅拌状态共沉淀，保持ｐＨ值在９－１１，沉淀经蒸馏水洗涤至无氯离子检出为止，经干燥后在３５０－５５０℃下焙烧，自然冷却至室温后，压片成型，破筛至４０－６０目。用浸渍法引入钯或银助剂，以硝酸盐的形式加入，浸渍时间为１２－２４小时，经红外灯照射烘干后制得催化剂。本发明具有催化剂机械强度好，性能重复性好，制备方法简单，易于操作的优点。

超临界CO2流体干燥制备纳米ZrO2的方法

一种超临界CO2流体干燥制备纳米ZrO2的方法是将氨水加入硝酸氧锆水溶液中，调节pH值到５－１０，陈化，抽滤，用乙醇置换凝胶中的水，得醇凝胶；超临界CO2流体连续通过醇凝胶，含有乙醇的CO2分离器，乙醇析出回收，CO2循环利用，待分离器中不再有乙醇析出时得到原粉；将原粉升温至６７３－１０７３Ｋ，保温，冷却，得到ZrO2粉体。本发明具有生产成本，工艺简单，容易控制，易于实现工业化的优点。

纳米粉掺杂的Y2O3-ZrO2陶瓷的制备

采用纳米粉掺杂烧结制备了Y203-ZrOz陶瓷。测试发现，纳米粉的掺入在一定程度上可以使烧结体的密度和硬度得到提高。SEM和EDS分析表明，烧结体表面比较平滑，元素分布比较均匀，有较小的气孔存在。

Co/ZrO2-SiO2废催化剂中钴锆的分离方法

一种Ｃｏ／ＺｒＯ↓［２］－ＳｉＯ↓［２］废催化剂中钴锆的分离方法是用二甲苯抽提掉废催化剂表面的有机物后，用稀硝酸溶解废催化剂中的金属钴，过滤，滤液经蒸发结晶得硝酸钴，滤渣用浓硫酸溶解，使废催化剂中的氧化钴物种和氧化锆以可溶性盐类存在，加入氢氧化钠溶液，出现Ｃｏ（ＯＨ）↓［２］和ＺｒＯ↓［２］ｘＨ↓［２］Ｏ沉淀，过滤后调节浆液的ｐＨ值在２－３，使Ｃｏ（ＯＨ）↓［２］沉淀溶解，与锆分离。过滤，滤饼经蒸发、焙烧后得二氧化锆，滤液经蒸发结晶得硝酸钴。本发明具有废催化剂中较贵重的钴和锆可同时分离、回收，方法简单，工艺流程短，回收产品纯度高，污染小的优点。

一种WOx-ZrO2超强酸催化剂的制备方法

一种简单易行的新型ＷＯ↓［ｘ］－ＺｒＯ↓［２］超强酸催化剂制备方法，具体地说是将无定形ＺｒＯ（ＯＨ）↓［Ｘ］与Ｈ↓［２］ＷＯ↓［４］机械混合均匀后再于８００－８２５℃高温焙烧；所述催化剂的组成成分及范围重量比为：Ｐｔ０．３－０．６ＺｒＯ↓［２］７５－９５ＷＯ↓［ｘ］５－２５，其中ＺｒＯ↓［２］∶ＷＯ↓［Ｘ］的重量比为４－２０∶１。本催化剂在２００－４００℃范围内，对ｎ－Ｃ↓［７］临氢转化反应具有极高的异构化选择性及较高的活性。

ZrO2前体的制备方法对WOx-/ZrO2性质及正庚烷临氢转化反应性能的影响

中国科学院山西煤炭化学研究所

铁的添加方式对Cu-Mn/ZrO2合成低碳醇催化剂的影响

中国科学院山西煤炭化学研究所

Cu/Mn/Ni/ZrO2合成低碳醇催化剂组分作用的初步研究

中国科学院山西煤炭化学研究所