碳自掺杂石墨相氮化碳纳米片的制备及其在可见光照射下的光解水产氢性能

石墨相氮化碳(g?C3N4)由于具有对可见光吸收范围较窄和光生载流子分离效率低等缺陷,其光解水产氢活性较差。我们采用简单的一步热共聚法,以尿素和2,4,6?三氨基嘧啶(TAPD)混合物为前驱物,制备碳自掺杂纳米片(CNNS?x,x mg代表掺入TAPD的质量)。X射线衍射(XRD)、元素分析(EA)和X射线光电子能谱(XPS)等测试结果表明,来自TAPD的嘧啶环成功引入g?C3N4共轭体系中,使所得的CNNS?x具有较窄的带隙,较快的光生载流子迁移速率,从而提高其对可见光的吸收效率和光生载流子的分离效率。得益于此,CNNS?x在可见光照射下表现出较好的光解水产氢活性。特别是CNNS?30具有最佳光解水性能,其产氢速率可达57.6μmol·h-1,是g?C3N4纳米片(CNNS)的4倍。

Preparation of Carbon Self-Doping Graphic Carbon Nitride Nanosheets for Photocatalytic H2 Evolution Performance under Visible-Light Irradiation

The photocatalytic activity of graphic carbon nitride(g?C3N4)was limited because of poor visible?light utilization and low photogenerated carriers separation.Herein,carbon self?doping g?C3N4(CNNS?x,x mg represents the mass of TAPD in precursor)was simply prepared by one?step thermal co?polymerization of the homogeneous mixture of urea and 2,4,6?triaminopyrimidine(TAPD).The as?prepared CNNS?x was carefully characterized by powder X?ray diffraction(XRD),elemental analysis(EA),and X?ray photoelectron spectroscopy(XPS),which indicated that the pyrimidine was incorporated into theπ?conjugated graphic carbon nitride.Thus,the CNNS?x was endowed with narrower bandgap,higher electric conductivity,which are favorable for improving the efficiency of visible?light absorption and photogenerated carrier separation.As a consequence,all the CNNS?x show remarkably improved performance in photocatalytic hydrogen evolution activity under visible?light irradiation.The optimum sample(CNNS?30)showed an excellent hydrogen evolution rate(~57μmol·h-1),which was up to 4 times higher than that of g?C3N4 nanosheets(CNNS).