Department of Environmental and Chemical Engineering Department, University of Calabria, Via P. Bucci 44A, 87036 Rende, CS (Italy).
Chemistry. 2014 Jan 3;20(1):187-94. doi: 10.1002/chem.201303689. Epub 2013 Dec 10.
There is much current interest in developing graphene-based materials as photocatalysts, particularly in the field of solar fuels and the photocatalytic generation of hydrogen. Graphene is a versatile material allowing different modification strategies to improve its activity. Thus, in the present manuscript we report that, in contrast to the lack of photocatalytic activity of undoped graphene, nitrogen doping introduces UV- and visible-light activity for hydrogen evolution; the efficiency of the material depends on the preparation conditions. The N-doped graphene is obtained by pyrolysis under an inert atmosphere of natural chitosan, which is considered a biomass waste, followed by ultrasound exfoliation, without the need of oxidation and reconstitution. The main parameter controlling the residual amount of nitrogen and the resulting photocatalytic activity is the pyrolysis temperature that produces an optimal material when the thermal treatment is carried out at 900 °C. Due to the fact that, in contrast to graphene oxide, N-doped graphene exhibits an almost "neutral" absorption spectrum, the material exhibits photocatalytic activity upon UV- (355 nm) and visible-light (532 nm) irradiation, and is able to generate hydrogen upon simulated sunlight illumination.
目前人们对将石墨烯基材料开发为光催化剂非常感兴趣，特别是在太阳能燃料和光催化制氢领域。石墨烯是一种多功能材料，可以采用不同的改性策略来提高其活性。因此，在本手稿中，我们报告说，与未掺杂石墨烯缺乏光催化活性相反，氮掺杂会引入用于氢产生的紫外光和可见光活性；材料的效率取决于制备条件。N 掺杂石墨烯是通过在惰性气氛下热解天然壳聚糖（被认为是生物质废料）获得的，然后进行超声剥离，而无需氧化和再合成。控制氮残留量和光催化活性的主要参数是热解温度，当在 900°C 下进行热解时，会产生最佳材料。由于与氧化石墨烯相比，N 掺杂石墨烯表现出几乎“中性”的吸收光谱，因此该材料在紫外光（355nm）和可见光（532nm）辐照下表现出光催化活性，并能够在模拟太阳光照射下产生氢气。
