Khoa Nguyen Tri, Kim Soon Wook, Yoo Dae-Hwang, Cho Shinuk, Kim Eui Jung, Hahn Sung Hong
Department of Physics and Energy Harvest-Storage Research Center and ‡Department of Chemical Engineering, University of Ulsan , Ulsan 680-749, South Korea.
ACS Appl Mater Interfaces. 2015 Feb 18;7(6):3524-31. doi: 10.1021/acsami.5b00152. Epub 2015 Feb 6.
Heterostructures of gold-nanoparticle-decorated reduced-graphene-oxide (rGO)-wrapped ZnO hollow spheres (Au/rGO/ZnO) are synthesized using tetra-n-butylammonium bromide as a mediating agent. The structure of amorphous ZnO hollow spheres is found to be transformed from nanosheet- to nanoparticle-assembled hollow spheres (nPAHS) upon annealing at 500 °C. The ZnO nPAHS hybrids with Au/rGO are characterized using various techniques, including photoluminescence, steady-state absorbance, time-resolved photoluminescence, and photocatalysis. The charge-transfer time of ZnO nPAHS is found to be 87 ps, which is much shorter than that of a nanorod (128 ps), nanoparticle (150 ps), and nanowall (990 ps) due to its unique structure. The Au/rGO/ZnO hybrid shows a higher charge-transfer efficiency of 68.0% in comparison with rGO/ZnO (40.3%) and previously reported ZnO hybrids. The photocatalytic activities of the samples are evaluated by photodegrading methylene blue under black-light irradiation. The Au/rGO/ZnO exhibits excellent photocatalytic efficiency due to reduced electron-hole recombination, fast electron-transfer rate, and high charge-transfer efficiency.
以四丁基溴化铵作为媒介剂，合成了金纳米粒子修饰的还原氧化石墨烯（rGO）包裹的ZnO空心球（Au/rGO/ZnO）异质结构。发现非晶态ZnO空心球的结构在500℃退火后从纳米片组装的空心球转变为纳米颗粒组装的空心球（nPAHS）。使用包括光致发光、稳态吸收、时间分辨光致发光和光催化在内的各种技术对具有Au/rGO的ZnO nPAHS杂化物进行了表征。发现ZnO nPAHS的电荷转移时间为87皮秒，由于其独特的结构，该时间比纳米棒（128皮秒）、纳米颗粒（150皮秒）和纳米壁（990皮秒）的电荷转移时间短得多。与rGO/ZnO（40.3%）和先前报道的ZnO杂化物相比，Au/rGO/ZnO杂化物显示出更高的68.0%的电荷转移效率。通过在黑光照射下光降解亚甲基蓝来评估样品的光催化活性。由于电子-空穴复合减少、电子转移速率快和电荷转移效率高，Au/rGO/ZnO表现出优异的光催化效率。
