熔融盐法制备Na掺杂的缺陷型g-C₃N₄

Preparation of Na-Doped Defect g-C₃N₄via Molten Salt Method

采用一步煅烧法,控制熔融盐NaCl的用量得到一系列Na掺杂的缺陷型g-C3N4。样品的物相和元素组成表征结果表明,所制备的样品是Na掺杂的g-C3N4,Na的掺杂导致g-C3N4中暴露了N缺陷,且随着NaCl用量的增加,g-C3N4中的缺陷浓度逐渐升高最终趋于饱和。Na掺杂的g-C3N4的光催化产H2O2性能明显优于纯相g-C3N4,当NaCl与尿素的比例为1/5时样品表现最佳光催化活性,达到1.17 mmol/(g•h)的H2O2产生速率。光电性能测试结果表明,g-C3N4中的N缺陷可以作为电子载体陷阱,捕获光生电子,促进光生电子空穴对的分离,而Na可以充当层间传输通道,促进光生电子的迁移。通过捕获剂实验以及EPR测定,确定光催化产H2O2过程中主要的活性物种为1O2。

By calcining different ratios of precursor urea and molten salt NaCl, defective g-C3N4 doped with different amounts of Na is obtained. The characterization results of the phase and element composition of asprepared samples showed that the samples are Na-doped g-C3N4, in which N defects are exposed and the amount of N defects in g-C3N4 tends to be saturated with the increase of the amount of NaCl. The photocatalytic H2O2 production activity of Na doped g-C3N4 is better than pure g-C3N4. When the mass ratio of NaCl/Urea was 1/5, g-C3N4 showed the best photocatalytic activity, reaching a rate of 1.17 mmol/(g•h). The photoelectric properties of samples exhibited that N vacancies can be acted as electron carrier traps to capture photogenerated electrons and promote the separation of photogenerated electronhole pairs, and Na can act as an interlayer transmission channel to promote the migration of photogenerated electrons. Through the capture agent experiment and EPR determination, it was determined that 1O2 is the main active species in the process of photocatalytic H2O2 production.