Graphene based catalysts for environmental and energy applications

当悬浮在水介质中的半导体光催化剂受光照射时，产生的带电物种(电子和空穴)移动到表面，产生非常活跃的氧化自由基，能够氧化溶液中存在的有机物质。产生的e--h+对也可以导致水分子分裂成元素氢和氧。因此，如果以太阳能为光源，光催化可用于去除难降解污染物并提供清洁能源；由于光催化在废物处理和提供清洁能源方面的巨大潜力，开发高活性的光催化剂是最活跃的研究领域之一。 在过去的几年里，我们的研究工作的一个重要部分是使用、合成和测试基于二氧化钛的催化剂来处理顽固的有机化合物，这些化合物抵抗传统的生物和化学处理。特别是，我们使用了商用的TiO2Degussa催化剂和紫外线辐射来处理来自不同行业的各种废水中的各种有机化合物，如电子加工和制药工业。我们还合成了具有高光催化活性的掺杂TiO2光催化剂，使可见光可以用于该过程。 本研究涉及我们实验室合成的石墨烯/二氧化钛纳米复合催化剂的应用，该催化剂具有广泛的应用前景。石墨烯是一种以蜂窝结构排列的二维碳原子的薄片，具有极大的比表面积、高透明度和良好的电子导电性等优异性能。这些性质使得它在用作电子和能量转换设备(如燃料电池)的催化剂以及光催化催化剂方面非常有吸引力。除了催化剂的合成及其对其性能的影响外，研究计划还将重点放在使用催化剂来销毁微电子加工和制药行业废水中发现的几种化合物。将使用三种类型的石墨烯：原始石墨烯(G)、氧化石墨烯(GO)和由麦吉尔等离子体处理实验室的等离子体合成(NG)产生的氮功能化石墨烯。实验工作将集中在催化剂的活性以及反应机理和中间产物的鉴定上。因此，除了为加拿大两个重要的工业领域(微电子和制药)开发环境友好的工艺和设备外，拟议的研究还有望增加我们对催化材料的性质、光催化反应的动力学和机理的了解，从而有助于我们对催化的基础知识。最后，预计至少有四名博士、三名硕士和几名本科生将在项目期间接受研究培训。

When a semiconductor photocatalyst which is suspended in an aqueous medium is irradiated by light, the generated charged species (electron and holes) travel to the surface to produce very active oxidizing radicals that are capable of oxidizing organic material present in the solution. The generated e-- h+ pairs can also cause the splitting of the water molecule to elemental hydrogen and oxygen. Thus photocatalysis can be applied for cleaning up recalcitrant pollutants and provide clean energy source if solar energy is used as the light source; the development of photocatalysts with high activity is one of most active research fields because of the tremendous potential of photocatalysis in waste treatment and in providing clean energy. In the past several years, an important part of our research effort was on the use, synthesis and testing of TiO2 based catalysts for the treatment of recalcitrant organic compounds that resist conventional biological and chemical treatment. In particular, we have used the commercially-available TiO2 Degussa catalyst and UV radiation for the treatment of various organic compounds found in various waste water streams from diverse industries such electronics processing and pharmaceutical industry. We have also synthesized doped TiO2 catalyst with high photocatalytic activity so that visible light can be used for the process. The present proposed research is concerned with the use of graphene/TiO2 nanocomposite catalysts synthesized in our laboratory and which can be used in a wide range of applications. Graphene is a very thin sheet of two dimensional carbon atoms arranged in a honeycomb structure that has some outstanding properties such as extremely large surface area, high transparency and excellent electron conductivity. These properties make it very attractive for its use as a support for catalysts for electronic and energy conversion devices such as fuel cells as well as for photocatalysis. In addition to the synthesis of the catalyst and its effect on its properties the research program will focus on the use of the catalyst for the destruction of several compounds found in the waste waters from the microelectronics processing and pharmaceutical industries. Three types of graphene will be used: pristine graphene (G), graphene oxide (GO) and nitrogen functionalized graphene produced by plasma synthesis (NG) in the Plasma Processing Laboratory at McGill. The experimental work will focus on the activity of the catalyst and the identification of the reaction mechanism and intermediate products. Thus in addition to the development of environmentally friendly processes and devices for two important industrial areas in Canada (microelectronics and pharmaceuticals), the proposed research is expected to increase our understanding of the properties of the catalytic materials, kinetics and mechanisms of the photocatalytic reactions thus contributing to our fundamental knowledge of catalysis. Finally it is expected that at least four Ph.D., three Masters and several undergraduate students will receive training in research during the program.