Study on Electrocatalytic Oxidation of sec-Butyl Alcohol on Pt Electrode Modified with Adatoms

运用电化学循环伏安和石英晶体微天平研究了HClO4溶液中仲丁醇在Pt电极及以Sb和S吸附原子修饰的Pt(Pt/Sbad和Pt/Sad)电极上的电催化氧化过程 .从电极表面质量变化可以看出 ,仲丁醇的氧化与电极表面的氧物种有着极其密切的关系 .Pt电极表面Sb吸附原子可在较低的电位下吸附氧 ,明显提高仲丁醇的氧化活性 .与Pt电极相比 ,Sb吸附原子修饰的Pt电极使仲丁醇氧化的峰电位负移约 10 0mV .相反 ,Pt电极表面S吸附原子的氧化会消耗表面氧物种 ,抑制仲丁醇的氧化 .从电极表面质量变化提供了吸附原子电催化作用的数据The processes of adsorption and oxidation of sec butyl alcohol on Pt electrode and Pt electrodes modified with Sb and S (Pt/Sb ad and Pt/S ad ) were studied by using cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The results demonstrated that the oxidation of sec butyl alcohol depends strongly on oxidation states of electrode surface. Sb adatoms on Pt surface can adsorb oxygen at relatively low potentials, and exhibit catalytic effects for sec butyl alcohol oxidation. In comparison with the case of Pt electrode, the oxidation peak potential of sec butyl alcohol on Pt surface modified with Sb was negatively shifted about 100 mV. On the contrary, the oxidation of S adatoms consumes oxygen species on Pt electrode surface. As a consequence, the oxidation of sec butyl alcohol was inhibited by the presence of S ad . The EQCM studies provided quantitative results of surface mass changes during sec butyl alcohol oxidation, and have thrown new light on elucidating different effects of adatoms Sb ad and S ad on Pt electrode towards sec butyl alcohol oxidation.国家自然科学基金 (2 983 3 0 60 );; 教育部博士点专项科研基金 (19990 3 840 3 );; 福建省教委科研基金资助项目 (K2 0 0 110 1

Study on electrocatalytic oxidation of sec-butyl alcohol on pt electrode modified with adatoms

The processes of adsorption and oxidation of sec-butyl alcohol on Pt electrode and Pt electrodes modified with Sb and S (Pt/Sb-ad and Pt/S-ad) were studied by using cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). The results demonstrated that the oxidation of sec-butyl alcohol depends strongly on oxidation states of electrode surface. Sb adatoms on Pt surface can adsorb oxygen at relatively low potentials, and exhibit catalytic effects for sec-butyl alcohol oxidation, In comparison with the case of Pt electrode, the oxidation peak potential of sec-butyl alcohol on Pt surface modified with Sb was negatively shifted about 100 mV. On the contrary, the oxidation of S adatoms consumes oxygen species on Pt electrode surface. As a consequence, the oxidation of sec-butyl alcohol was inhibited by the presence of S-ad. The EQCM studies provided quantitative results of surface mass changes during sec-butyl alcohol oxidation, and have thrown new light on elucidating different effects of adatoms Sb-ad and S-ad on Pt electrode towards sec-butyl alcohol oxidation

掺镨GaN薄膜的微结构与光致发光

利用背散射／沟道（RBS／C）技术、原子力显微镜（AFM）和光致发光（PL）谱研究了掺镨GaN薄膜的微结构和可见光发光特性。RBS／C结果表明，注入Pr后，在注入层引入了晶格损伤；注入样品经1050℃退火后，部分损伤得到恢复，但是晶体质量没有恢复到注入前的状态。AFM结果表明，注入Pr后，表面凹凸不平，而且在注入区引起了膨胀，膨胀幅度达到23．368nm左右。PL结果表明，在850—1050℃退火，发光强度按e指数增加；当退火温度达到1050℃，发光强度最强，经过数据拟合可得Pr^3＋的热激活能为5．8eV

掺稀土半导体光电特性和应用

结合我们近年来在掺稀土硅基材料和Ⅲ-Ⅴ族化合物半导体材料的发光研究，简述目前国际上在这方面研究的新进展，重点介绍掺铒硅基发光和掺稀土GaN发光材料和器件的研究结果

掺铒GaN薄膜光致发光的研究

采用傅立叶变换红外光谱（FT－IR）研究了掺铒GaN薄膜光致发光特性，光致发光谱（PL）的测量结果表

掺Er/Er+O的GaN薄膜光学性质的研究

利用Raman散射谱研究了GaN注Er以及Er+O共注样品的振动模，并讨论了共注入O对Er离子发光的影响. 在Raman散射谱中，对于注Er的GaN样品出现了300 cm~(-1)和670 cm~(-1)两个新的Raman峰，而对于Er+O共注样品，除了上述两个峰外，在360 cm~(-1)处出现了另外一个新的峰，其中300 cm~(-1)峰可以用disorder-activated Raman scattering (DARS)来解释，670 cm~(-1)峰是由于与N空位相关的缺陷引起的，而360 cm~(-1)峰是由O注入引起的缺陷络合物产生的. 由于360 cm~(-1)模的缺陷出现，从而导致Er+O共注入GaN薄膜红外光致发光(PL)强度的下

掺Er／Pr的GaN薄膜深能级的研究

利用深能级瞬态谱（DLTS）、傅里叶变换红外光谱（FT-IR）对GaN以及GaN掺Er／Pr的样品进行了电学和光学特性分析．研究发现未掺杂的GaN样品只在导带下0．270eV处有一个深能级；GaN注入Er经900℃，30min退火后的样品出现了四个深能级，能级位置位于导带下0．300eV，0．188eV，0．600eV和0．410eV；GaN注入Pr经1050℃，30min退火后的样品同样出现了四个深能级。能级位置位于导带下0．280eV，0．190eV，0．610eV和0．390eV；对每一个深能级的来源进行了讨论．光谱研究表明，掺Er的GaN样品经900℃，30min退火后，可以观察到Er的1538nm处的发光。而且对能量输运和发光过程进行了讨论

掺铒nc-Si/SiO_2薄膜中nc-Si和Er~(3+)与非辐射复合缺陷间相互作用对薄膜发光特性的影响

对nc-Si/SiO_2薄膜中纳米硅(nc-Si)、Er~(3+)和非辐射复合缺陷三者间的关系作了研究.在514.5 nm光激发下,nc-Si/SiO_2薄膜在750nm和1.54μm处存在较强的发光,前者与薄膜中的nc-Si有关,后者对应于Er~(3+)从第一激发态4I13/2到基态4I15/2的辐射跃迁.随薄膜中Er3+含量的提高,1.54μm处的发光强度明显增强,750 nm处的发光强度却降低.H处理可以明显增强薄膜的发光强度,但是对不同退火温度样品,处理效果却有所不同.根据以上实验结果,可得如下结论:在nc-Si颗粒附近的Er~(3+)和其他的缺陷组成了nc-Si颗粒内产生的束缚激子的非辐射复合中心,束缚激子通过Er~(3+)的非辐射复合,激发Er~(3+)产生1.54μm处的发光,同时降低了750nm处的发光强度.nc-Si颗粒附近其他非辐射复合中心的存在会降低Er~(3+)被激发的概率,引起1.54μm处的发光强度降低