g-C3N4和CuO复合材料的制备、表征及光催化研究

高温煅烧三聚氰胺制备类石墨结构氮化碳(g-C3N4),然后以硝酸铜Cu(NO3)2和g-C3N4为原料,去离子水和无水乙醇作溶剂,在加入适量氨水的反应条件下通过水热法反应制备g-C3N4/CuO纳米复合材料.采用场发射扫描电子显微镜(FE-SEM)、光电子能谱仪(XPS)、紫外可见漫反射(UV-Vis-DRS)和荧光光谱(PL)等测试对复合材料进行表征.通过XRD、SEM和XPS测试结果可知微米球形CuO和g-C3N4紧密的结合起来,而由UV和PL谱图表明CuO和g-C3N4的复合扩展了材料对可见光的吸收范围和减慢了材料的光生电子和空穴的复合率.通过在可见光下降解甲基橙(MO)来检测复合材料的光催化活性,结果表明,在没有过氧化氢(H2O2)的体系下,经过4 h的光反应后,70-g-C3N4/CuO对MO的降解率达到了85;;但是在H2O2的体系下,经过1 h光反应后,70-g-C3N4/CuO对MO的降解率达到了96;.通过自由基的捕获实验说明羟基自由基、超氧自由基、空穴在降解MO过程中起到重要的作用.复合材料在经过四次的循环实验后,对MO的降解率基本能达到90;.因此,g-C3N4和CuO的复合抑制了电子-空穴的复合和扩展了吸收光波长范围,这样就使g-C3N4/CuO材料有了好的光催化性和稳定性.

Synthesis,Characterization and Photocatalytic Property of g-C3N4/CuO Composite

Graphitic carbon nitride (g-C3N4) was prepared by the thermal condensation of melamine.Then, A g-C3N4/CuO nano composite materials were prepared using Cu(NO3)2 and g-C3N4 as raw material under hydrothermal method in present of amount of ammonia with deionized water and anhydrous ethanol as solvent.The obtained photocatalyst was characterized by field emission scanning electron microscope (FE-SEM), photoelectron spectrometer (XPS) and uv-vis diffuse reflection (UV-Vis-DRS) and fluorescence spectroscopy (PL).According to the XRD, SEM and XPS test result, micro spherical CuO and g-C3N4 closely together;the UV and PL spectra show that the combination of CuO and g-C3N4 composite can expand the scope of visible light absorption and slows down the compound rate of electrons and holes.The degradation of methyl orange (MO) aqueous solution was used to evaluate the photocatalytic activity of 70-g-C3N4/CuO under visible light irradiation.The results show that in the absence of hydrogen peroxide (H2O2) system, the degradation rate of MO remains 85; after 4 h of light reaction,but the existence of H2O2 system, the photodecomposition rate of MO reached 96; after 1 h light reaction.Through laboratory experiments on the trapping free radicals, hydroxyl free radical and hole played an important role in the process of degradation of MO.After four times of circulation, the basic for the degradation of MO rate still reached 90;.Thus the g-C3N4/CuO material had good photocatalytic and stability.