Wang Fangxiao, Chen Yanglin, Zhu Rongshu, Sun Jianmin
State Key Laboratory of Urban Water Resource and Environment, MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150090, China.
Dalton Trans. 2017 Aug 29;46(34):11306-11317. doi: 10.1039/c7dt01528c.
Magnetic visible-light-driven photocatalyst, porous C/ZnFeO (denoted as C/ZFO-CE) was fabricated via a CO-mediated ethanol route. CO-mediated ethanol route largely mitigated the solvent strength and facilitated the homogenous deposition of ZnFeO (ZFO) through the coordination of metallic cation with CO and HCO anions, which were hydrolyzed from CO and HO, thereby avoiding additional precipitant. Moreover, the HCO, CO and NO in the system acted as templates for the formation of porous C avoiding the additional organic mesoporous templates, thus reducing the synthesis cost. For the degradation of RhB and phenol, the C/ZFO-CE system in presence of minute HO exhibited remarkably improved catalytic performance compared with the systems of HO, ZFO, C/ZFO-CE, C/ZFO-E (C/ZnFeO synthesized in pure ethanol) and C/ZFO-E in the presence of minute HO. Furthermore, 2.0 mL of HO (30%) combined with C/ZFO-CE obtained the maximum degradation efficiencies of 100% for RhB within 60 min and 91% for phenol within 120 min. The high efficiency for degradation of pollutants over C/ZFO-CE catalyst in the presence of minute HO was possibly attributed to the strong harvest of visible light, the improved separation efficiency of the photoinduced charges and the overall ˙OH production by the "photo-Fenton" process. The existence of ˙OH during photodegradation process was evidenced via the PL-TA (photoluminescence-terephthalic acid) technique, ESR spectra and trapping experiments of active species using different scavengers. Furthermore, a possible reaction mechanism involving the Fenton-like reaction for the photodegradation of pollutants is proposed based on the experimental results.
通过CO介导的乙醇路线制备了磁性可见光驱动的光催化剂多孔C/ZnFeO（表示为C/ZFO-CE）。CO介导的乙醇路线大大降低了溶剂强度，并通过金属阳离子与由CO和H₂O水解产生的CO₃²⁻和HCO₃⁻阴离子的配位作用促进了ZnFeO（ZFO）的均匀沉积，从而避免了额外的沉淀剂。此外，体系中的HCO₃⁻、CO₃²⁻和NO₃⁻作为形成多孔C的模板，避免了额外的有机介孔模板，从而降低了合成成本。对于RhB和苯酚的降解，与H₂O₂体系、ZFO体系、C/ZFO-CE体系、C/ZFO-E（在纯乙醇中合成的C/ZnFeO）体系以及在微量H₂O₂存在下的C/ZFO-E体系相比，在微量H₂O₂存在下的C/ZFO-CE体系表现出显著提高的催化性能。此外，2.0 mL的H₂O₂（30%）与C/ZFO-CE组合在60分钟内对RhB的降解效率达到100%，在120分钟内对苯酚的降解效率达到91%。在微量H₂O₂存在下，C/ZFO-CE催化剂对污染物的高效降解可能归因于对可见光的强烈捕获、光生电荷分离效率的提高以及“光芬顿”过程中整体˙OH的产生。通过PL-TA（光致发光-对苯二甲酸）技术、ESR光谱以及使用不同清除剂的活性物种捕获实验证明了光降解过程中˙OH的存在。此外，基于实验结果提出了一种可能的涉及类芬顿反应的污染物光降解反应机理。
