g-C3N4/ZnO hybrid material as photocatalyst for photocatalytic CO2 reduction

• Main Author: Hu, Zhaoning
• Other Authors: Xue Can
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering::Materials::Composite materials
• Online Access: http://hdl.handle.net/10356/66378
• Institution: Nanyang Technological University

The climate change resulting from the increasing emission of greenhouse gases in atmosphere has become a serious global environmental issue. Among total amount of the greenhouse gases, CO2 is the principal one and takes account of 76%. To overcome this issue, extensive research has been done upon a process of photocatalytic reduction of CO2 into hydrocarbon fuels. This photocatalytic reduction process has drawn lots of attention for it can decrease the amount of CO2 and generate solar fuels at the same time. ZnO has been widely studied as a photocatalyst for the CO2 photocatalytic reduction process, for it is abundant, nontoxic and stable. Among the various morphologies of ZnO, ZnO one-dimensional (1D) nanowire has high specific surface area and high charge carrier mobility, therefore it is a promising photocatalyst. Graphitic carbon nitride (g-C3N4) is an organic polymer which is under intensive study recently for CO2 photoreduction. It has favorable energy band to reduce CO2, nice CO2 fixation capability and able to harvest energy from visible light region. By adding g-C3N4 on ZnO nanowire as cocatalyst, a higher CO2 conversion efficiency is expected. In this study, a hybrid material is synthesized by growing g-C3N4 on ZnO nanowire following a solvothermal method. Characterizations including SEM, XRD, FT-IR, EDX and UV-visible spectroscopy have been done. The result shows a layer of tri-s-triazine structured g-C3N4 in spherical shape is grown on top of ZnO nanowire. The gas performance test results show this hybrid material has much larger CO and CH4 yield rate compared to clean ZnO nanowire and pure g-C3N4. Further study could concentrate on exploring the detailed mechanism in g-C3N4 synthesizing process, finding the optimal amount of g-C3N4 in the hybrid material and trying alternative g-C3N4 synthesizing method to grow g-C3N4 on other ZnO morphologies to get better photocatalytic CO2 reduction performance.