Effect of Cu on dehydrogenation and thermal stability of amorphous Mg-Ce-Ni-Cu alloys

The alloying element component is very crucial in improving the hydrogen storage performance of amorphous alloys.In this work,quaternary amorphous Mg_(70-x)Ce_(10)Ni_(20)Cu_x(x=3,7.5,10)alloys were prepared by meltspinning and the effect of Cu on hydrogenation and dehydrogenation were investigated in comparison with the Mg_(70-x)Ce_(10)Ni_(20)amorphous alloys.The initial hydrogenation kinetics of amorphous Mg_(70-x)Ce_(10)Ni_(20)Cu_x(x=0,3,7.5,10)was improved with the increase of Cu content according to the kinetics measured at a temperature below crystallization temperature.As hydrogen is absorbed,an amorphous-amorphous transition occurred,and relatively high Cu content would lead to phase separation in the hydrogenation process.Amorphous phase have much higher crystallization temperature after it absorbs hydrogen and the addition of Cu could increase the crystallization activation energy of amorphous hydrides.In addition,the increase of Cu content could reduce the dehydrogenation temperature of amorphous hydrides,which gives a significant indication for future improving research of the hydrogen desorption performance of Mg based amorphous hydrides.     

促进剂对乙醇水溶液光催化脱氢性能的影响

考察了担载各种不同过渡金属的CdS粉末光催化剂的脱氢活性,得出活性顺序为Pd(5％)/CdS(化学镀)>Pt(5％)/CdS(机械混合或化学镀)>Rh_2O_3(1％)/CdS(机械混合),否定了Cu和Ag作为主催化组分的可能性,在Pt/CdS体系中,Pt的最佳担载量为5％左右,研究了包括第二金属组分作为可能的促进剂的双金属组分M_1+M_2/Cds光催化剂的脱氢活性,肯定了Cu和Ag是Pt/CdS和Pd/CdS体系的良好促进剂,有明显助催作用.实验证明Pt(5％)+Cu(5％)/CdS为这两种金属组分的最佳匹配量。     

FeZSM-5分子筛中平衡阳离子与乙苯脱氢活性的关系研究(Ⅱ)

本文采用阳离子交换法对FeZSM-5分子筛进行改性,利用乙苯的吸附扩散性能评价阳离子对分子筛孔道的修饰作用,证明骨架铁是催化乙苯脱氢反应的活性中心,金属阳离子对分子筛结构的修饰对乙苯脱氢影响不起主要作用,而对骨架铁的极化作用才是乙苯脱氢活性改变的真正原因。     

甲醇催化脱氢新型催化剂的研究

研究甲醇催化脱氢ＺｎＯ／ＳｉＯ＿２催化剂及其添加剂的助催效应，并用ＥＤＡＸ和ＴＰＤ─ＭＳ法表征催化剂表面性质．结果表明：添加剂对甲醛产率的影响次序为Ｎｉ＞＞Ｍｇ＞Ｌｉ；不同制备方法改变表面Ｚｎ：Ｓｉ比．根据热力学平衡和主付反应产物的分布讨论了反应推理．     

Pt-Sn-碱/r-Al_2O_3催化剂中氯和碱含量对戊烷脱氢的影响

以Pt-Sn/r-Al_2O_3工业催化剂为基础.考察了催化剂中氧及碱金属助剂含量对正戊烷脱氩活性和选择性的影响规律.阐明了脱氢活性、选择性及催化剂抗积炭能力与催化剂表面酸性的依赖关系.研究结果表明,添加一定含量的碱助剂可明显调变催化剂表面强酸中心,有效地抑制催化剂上的酸性反应,使脱氢活性有所加强,进而显著地提高催化剂的脱氢选择性和抗积炭能力.基础催化剂脱氯后再添加碱金属,可获得类似效果。     

第四周期过渡金属对乙苯脱氢催化剂的助催化作用

第四周期过渡金属对乙苯脱氢催化剂的助催化作用祝以湘，夏明，何淡云（化工系物理化学研究所）Ｆｅ＿２Ｏ＿３－Ｋ＿２Ｏ系乙苯脱氢催化剂一般由铁、碱／碱土金属和过渡金属氧化物三部分组分。后者中，第四周期过渡金属经常被各种牌号的工业催化剂所选用（表１）。人们曾...