基于纳米镍催化的松香加氢研究--树酯酸组成的研究

松香的主要成份是枞酸型树脂酸,其因共轭双键的存在而易被氧化,大大降低了其附加值。经氢化后的松香具有抗氧性好、脆性小、热稳定性高、颜色浅等特点,因而广泛应用于胶粘剂、合成橡胶、涂料、油黑、造纸、电子、食品等工业部门[1]。采用催化加氢的方法可使枞酸型树脂酸中的共轭双键消除[2]。以枞酸为代表的反应式为:松香催化加氢主要有熔融法[3]和溶剂法[4],所用催化剂主要是Pd和N i。熔融法制氢化松香,当反应温度低于200℃时,枞酸加氢速度较慢,反应不完全。温度升高,氢化松香中枞酸含量显著地减少,但温度高于250℃时,树脂酸脱羧严重,甚至…     

单分散纳米Ni(OH)2的制备及其电化学性能

表面活性剂;单分散纳米Ni(OH)2的制备及其电化学性能     

聚乙烯醇对光还原Ni~(2+)制备纳米Ni性能及染料敏化制氢的影响

采用染料曙红-Y(EY)作为敏化剂将Ni~(2+)光还原制备纳米Ni.在该反应体系中,不加入PVA时,光还原所得到的纳米Ni为球状粒子;而加入PVA,由于其模板导向作用,多数纳米镍呈现棒状.吸附在Ni表面的PVA能够促进光生电子从EY向棒状镍转移,从而提高其染料敏化制氢的活性和稳定性.     

The relationship of spherical nano-Ni(OH)2 microstructure with its voltammetric behavior

The spherical nano-Ni(OH)₂ has been characterized by a series of spectra methods such as the scanning electron microscope (SEM), the transmission electron microscope (TEM) and the X-ray diffraction (XRD). The electrochemical behavior of spherical nano-Ni(OH)₂, attached to a graphite electrode and adjacent to an aqueous KOH-KCl electrolyte solution, has been studied by cyclic voltammetry. Spherical nano-Ni(OH)₂ exhibits a pair of quasi-reversible redox peaks. The relationship of the granularity and the potential was investigated, as well as the effect of different pH conditions. Moreover, the cycling experiments have been set up using spherical nano-Ni(OH)₂ and traditional analytical grade Ni(OH)₂, respectively, and their cycling performances were evaluated as well. The capacity of spherical nano-Ni(OH)₂ is ca. ten times higher than the one with the traditional material under the same conditions, which shows its better electrochemical properties.     

纳米级复合氢氧化镍的循环伏安研究

采用低温固相法和有机液相法制备氢氧化镍及化学掺杂金属阳离子的复合氢氧化镍,TEM测试表明合成出的样品均为纳米级复合氢氧化镍;循环伏安测试,发现样品还原峰电位值(E_R)与掺杂阳离子的电荷半径比(z/r值)呈现一定的关系,表现为电荷半径比越大,样品还原峰电位值也越大.由此得出一个经验关系式,并且从晶体结构方面就还原峰电位值与掺杂金属阳离子的电荷半径比之间的关系以及聚乙二醇表面活性剂对掺杂样品的影响进行了探讨.认为掺杂高价金属阳离子容易形成α-氢氧化镍,它是样品还原峰电位值增大的原因.此外,聚乙二醇通过与掺杂金属阳离子配位作用同样会影响样品的还原峰电位值.