Han Noh Soo, Kim Dukhan, Lee Jong Woon, Kim Jaehyun, Shim Hyeong Seop, Lee Yongjin, Lee Dongil, Song Jae Kyu
Department of Chemistry, Kyung Hee University , Seoul 130-701, Korea.
Department of Chemistry, Yonsei University , Seoul 120-749, Korea.
ACS Appl Mater Interfaces. 2016 Jan 20;8(2):1067-72. doi: 10.1021/acsami.5b09987. Epub 2016 Jan 8.
Semiconductor-metal nanocomposites prepared with well-defined gold nanoclusters, such as Au25, Au144, and Au807, showed size-dependent photocatalytic activities for the reduction of nile blue and azobenzene. Whereas the photoreduction of nile blue was directly related with the charge separation and transfer rate from the photoexcited ZnO to gold nanoclusters, the photoreaction of azobenzene showed unexpected size effect with a clear threshold. Mechanistic investigations revealed that the photoreduction of azobenzene proceeded via a proton-coupled electron transfer process. The photocatalytic activity of the ZnO-Au nanocomposites was also dependent on the excitation intensity, demonstrating that the multielectron/multiproton process was controlled by the charge separation and transfer in the nanocomposites.
用定义明确的金纳米团簇（如Au25、Au144和Au807）制备的半导体-金属纳米复合材料，对尼罗蓝和偶氮苯的还原表现出尺寸依赖性的光催化活性。尼罗蓝的光还原与从光激发的ZnO到金纳米团簇的电荷分离和转移速率直接相关，而偶氮苯的光反应则表现出意想不到的尺寸效应，有一个明确的阈值。机理研究表明，偶氮苯的光还原是通过质子耦合电子转移过程进行的。ZnO-Au纳米复合材料的光催化活性也取决于激发强度，表明多电子/多质子过程受纳米复合材料中的电荷分离和转移控制。
