Som, T.; Troppenz, G.; Wendt, R.; Wollgarten, M.; Rappich, J.; Emmerling, F.; Rademann, K.: Graphene Oxide/α-Bi2O3 Composites for Visible-Light Photocatalysis, Chemical Catalysis and Solar Energy Conversion. ChemSusChem 7 (2014), p. 854-865
10.1002/cssc.201300990
Open Accesn Version
Abstract:
The growing challenges of environmental purification by solar photocatalysis, precious metal free catalysis and photocurrent generation in photovoltaic cells are receiving the utmost global attention. Here we demonstrate the one-pot green chemical synthesis of a new stable heterostructured, eco-friendly, multifunctional micro-composite consisting of α-Bi2O3 micro-needles intercalated with anchored graphene oxide (GO) micro-sheets (1.0 wt%) for the above mentioned applications in a large economical scale. The bare α-Bi2O3 micro-needles display twice as better photocatalytic activities than commercial TiO2 (Degussa-P25) while the GO hybridized composite exhibit ~4-6 times enhanced photocatalytic activities than neat TiO2 photocatalyst in the degradation of colored aromatic organic dyes (crystal violet and rhodamine 6G) under visible light irradiation (300 W tungsten lamp). The highly efficient activity is associated with the strong surface adsorption ability of GO for aromatic dye molecules, the high carrier acceptability and efficient electron-hole pair separation in Bi2O3 by individual adjoining GO sheets. Introduction of Ag nanoparticles (2.0 wt%) further enhances the photocatalytic performance of the composite over 8 folds due to a plasmon-induced electron-transfer process from Ag nanoparticles via GO sheets into the conduction band of Bi2O3. The new composites are also catalytically active. They catalyze the reduction of 4-nitrophenol to 4-aminophenol in presence of borohydride ions. Photoanodes assembled from GO/α-Bi2O3 and Ag/GO/α-Bi2O3 composites display an improved photocurrent response (power conversion efficiency ~ 20% higher) over those prepared without GO in dye-sensitized solar cells (DSSCs).