High-yield synthesis, optical properties and photocatalytic performance of graphitic carbon nitride
Date of Issue2016-06-10
School of Physical and Mathematical Sciences
Graphitic carbon nitride (g-C3N4), an emerging graphene-like two-dimensional (2D) material, has received wide attention by its fascinating photocatalytic performances as a photocatalyst in a variety of photocatalytic reactions such as photocatalytic water splitting and photocatalytic degradation. Owing to a bandgap of 2.7 eV, g-C3N4 is able to make use of the renewable and sustainable solar energy and conduct photocatalytic reaction under visible-light. Moreover, g-C3N4 is inexpensive, abundant and eco-friendly. It also has high thermal and chemical stability. Therefore, researchers believe that g-C3N4 is the most promising photocatalyst to serve in environmental protection and energy conservation. Studies on the chemical, optical and photocatalytic properties of g-C3N4 is very important and of great interests to the public. In the thesis, we report the synthesis, characterizations, and photocatalytic application of g-C3N4 products. High-yield synthesis of g-C3N4 powder via sealed heating method and half-sealed heating method are demonstrated. Based on the g-C3N4 powder, the g-C3N4 films are further produced by vacuum heating deposition and thermal evaporator. The chemical composition and crystallization of the as-prepared g-C3N4 products are demonstrated by multiple characterizations such as thermal gravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning transmission electron microscopy and electron energy loss spectroscopy. On the other hand, a systematic optical study of g-C3N4 is carried out with several approaches. Using infrared and Raman spectroscopy, the chemical band vibrational modes of g-C3N4 products are revealed, and the absorption and emission property of g-C3N4 are investigated by UV-visible spectroscopy and photoluminescence spectroscopy. Moreover, the photocatalytic property of g-C3N4 is explored by the photodegradation experiment. We also build g-C3N4\hematite heterojunctions and study its photocatalytic water splitting performance.