铁掺杂类石墨相氮化碳类芬顿/光催化氧化作用机制

Mechanism of Iron-doped Graphite-like Carbon Nitride Fenton-like/Photocatalytic Oxidation

采用热聚合法制备并优化了不同铁掺杂比的铁掺杂类石墨相氮化碳(Fe-g-C3N4)类芬顿光催化剂,铁元素可完全掺杂进入类石墨相氮化碳(g-C3N4)结构中并组成Fe—N配位键,最佳的Fe掺杂比为10%(质量分数)。Fe-g-C3N4类芬顿/光催化氧化对罗丹明B的降解速率和降解率均远高于g-C3N4的,反应10 min时降解率已达到87.9%,反应过程中起主要作用的活性基团为羟基自由基,超氧自由基和空穴电子也有一定作用。在pH值为3~9范围内,Fe-g-C3N4类芬顿/光催化氧化对罗丹明B的降解率均高于90%,大幅度拓宽了适用范围;H2O2的投加量会显著影响Fe-g-C3N4类芬顿/光催化氧化的降解效能,H2O2最佳投量范围为1.0~1.5 mmol/L。

Iron-doped graphite-like carbon nitride(Fe-g-C3 N4)Fenton-like photocatalyst was prepared by using thermal polymerization and optimized by adjusting the iron-doped ratios.The optimal iron-doped ratio was 10%,and iron element could be completely doped into the graphite-like carbon nitride(g-C3 N4)structure and formed Fe-N coordination bond.The degradation velocity and degradation rate of rhodamine B by Fe-g-C3 N4 Fenton-like/photocatalytic oxidation were much higher than those of g-C3 N4.The degradation rate of rhodamine B reached up to 87.9%after 10 minutes of reaction.The main active oxygen species were hydroxyl radicals,followed by superoxide radicals and hole electrons.The degradation rate of rhodamine B by Fe-g-C3 N4 Fenton-like/photocatalytic oxidation was always more than 90%when the pH was in the range of 3-9,which greatly broadened the scope of application.The dosage of H2 O2 greatly influenced the degradation efficiency of Fe-g-C3 N4 Fenton-like/photocatalytic oxidation,and its optimal dosage was between 1.0 mmol/L and 1.5 mmol/L.