Fabrication, mechanism, formic acid-tuned degradation and photocatalytic hydrogen production of novel modified ZnO spheres by L - TA - DMF assisted hydrothermal method

Many ZnO microspheres were fabricated by hydrothermal method using L-TA and DMF as double capping agents. These spheres possess many novel nanostructures and exhibit unique and flexible self - assemblies and building units. For example, diverse pattern-like spheres, core/shell spheres, and semispheres were obtained. FTIR spectra of S1-S9 show TA and HCOOH modified ZnO spheres, which agree with those of XPS analysis. PL spectra show that violet, blue, green, yellow and orange emissions generated simultaneously can be tuned. E-g and epsilon are influenced by c. TA and DMF lead to diverse and novel ZnO growth, while DMF can tune the number of surface active sites of exposed (002) facet of ZnO, which determines final photocatalytic efficiency. TOC results show most of MB are mineralized rather than being partially degraded. The photocatalytic H-2 generation rate is 4.15 ml h(-1) g(-1) under simulated sunlight irradiation. In addition, DMF - induced photocatalytic mechanisms and two self-assemblies were proposed.