酶法催化二氧化碳制备高附加值化学品研究进展

现代工业的发展不断消耗煤、石油、天然气等碳化石燃料,并产生了大量的温室气体CO₂,使人类面临能源和环境的双重挑战,开发绿色能源、控制CO₂对环境的影响迫在眉睫.CO₂是一种廉价的碳源,可通过化学法、光化学法、电化学法或酶法等转化为高附加值含碳化学品,实现CO₂的资源化循环利用,是解决全球碳排放所带来的能源和环境危机的双赢策略.受CO₂胞内天然生物转化的启发,酶法为CO₂的循环利用带来了新的机遇,相比于传统的化学及光、电化学法,可表现出绿色、高效、温和、高选择性等优点,有望为CO₂高值化利用带来新的契机.有鉴于此,本文从胞内CO₂生物转化机理出发,综述了国内外近年来多种单酶及多酶级联催化CO₂高值化利用的最新研究进展,并交叉论述了固定化酶催化体系的构建、酶定向进化和改造、酶催化过程调控等内容,总结了酶法转化目前存在的缺陷和不足,并提出了展望,以期为酶法催化CO₂高值化利用提供一定的参考和借鉴.     

Au-Ag复合纳米阵列的制备及其等离激元共振吸收特性

利用二次阳极氧化法在硫酸体系中制备了多孔氧化铝模板,用交流法在模板中沉积了Au-Ag复合纳米阵列,并研究了其表面等离激元共振吸收特性.和单独的Au、Ag纳米线阵列不同,Au-Ag复合纳米阵列的紫外可见吸收光谱中有两个横向吸收峰,一个纵向共振吸收峰.Au-Ag复合纳米阵列的纵向等离共振波长可以通过改变Ag的生长时间进行有效调节.实验结果发现,Au沉积对后续沉积Ag的最佳沉积电压有影响.     

Facile Synthesis of Au Nanocube-CdS Core-Shell Nanocomposites with Enhanced Photocatalytic Activity

Au nanocube-CdS core-shell nanocomposites are prepared by using a one-pot method in aqueous phase with cetyltrimethylammonium bromide as the surfactant. The extinction properties and photocatalytic activity of Au-CdS nanocomposites are investigated. Compared with the pure Au nanocubes, the Au-CdS nanocomposites exhibit enhanced extinction intensity. Compared with CdS nanoparticles, the Au-CdS nanocomposites exhibit improved photocatalytic activity. Furthermore, the photocatalytic et~ciency is even better with the increase in the core size of the Au-CdS nanocomposites. Typically, the photocatalytic efficiency of the Au-CdS with 62 nm sized Au nanocubes is about two times higher than that of the pure CdS. It is believed that the Au-CdS nanocomposites may find potential applications in environmental fields, and this synthesis method can be extended to prepare a wide variety of functional composites with Au cores.