Zhang Li-Sha, Cao Xu-Sheng, Yang Yefeng, Ye Zhizhen, Wu Jin-Ming
School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, PR China.
Zhejiang Provincial Engineering Research Center of Oxide Semiconductors for Environmental and Optoelectronic Applications, Institute of Wenzhou, Zhejiang University, Wenzhou 325006, PR China.
Langmuir. 2024 Feb 27;40(8):4424-4433. doi: 10.1021/acs.langmuir.3c03754. Epub 2024 Feb 18.
To develop versatile photocatalysts for efficient degradation of distinct organic pollutants in water is a continuous pursuit in environment remediation. Herein, we directly oxidize TiC MXene with hydrogen peroxide to produce C-doped anatase TiO nanowires with aggregates maintaining a layered architecture of the MXene. The TiC MXene provides a titanium source for TiO, a carbon source for in situ C-doping, and templates for nanowire aggregates. Under UV light illumination, the optimized TiC/TiO exhibits a reaction rate constant 1.5 times that of the benchmark P25 TiO nanoparticles, toward photocatalytic degradations of trace phenol in water. The mechanism study suggests that photogenerated holes play key roles on the phenol degradation, either directly oxidizing phenol molecules or in an indirect way through oxidizing first the surface hydroxyl groups. The unreacted TiC MXene, although with trace amounts, is supposed to facilitate electron transfer, which inhibits charge recombination. The unique nanostructure of layered aggregates of nanowires, abundant surface oxygen vacancies arising from the carbon doping, and probably the TiC/TiO heterojunction guarantee the high photocatalytic efficiency toward removals of organic pollutants in water. The photocatalyst also exhibits an activity superior to, or at least comparable to, the benchmark P25 TiO toward photodegradations for typical persistent organic pollutants of phenol, dye molecule of rhodamine B, antibiotic of tetracycline, pharmaceutical wastewater of ofloxacin, and pesticide of -dimethylformamide, when evaluated in total organic carbon removal.
开发用于高效降解水中不同有机污染物的多功能光催化剂是环境修复领域一直以来的追求。在此，我们用过氧化氢直接氧化TiC MXene，以制备具有聚集体的C掺杂锐钛矿型TiO纳米线，该聚集体保持了MXene的层状结构。TiC MXene为TiO提供钛源，为原位C掺杂提供碳源，并为纳米线聚集体提供模板。在紫外光照射下，优化后的TiC/TiO对水中痕量苯酚的光催化降解反应速率常数是基准P25 TiO纳米颗粒的1.5倍。机理研究表明，光生空穴在苯酚降解中起关键作用，既可以直接氧化苯酚分子，也可以通过先氧化表面羟基的间接方式。未反应的TiC MXene虽然含量极少，但被认为有助于电子转移，从而抑制电荷复合。纳米线层状聚集体的独特纳米结构、碳掺杂产生的丰富表面氧空位以及可能的TiC/TiO异质结保证了对水中有机污染物去除的高光催化效率。当以总有机碳去除率进行评估时，该光催化剂对苯酚、罗丹明B染料分子、四环素抗生素、氧氟沙星制药废水和二甲基甲酰胺农药等典型持久性有机污染物的光降解活性也优于或至少与基准P25 TiO相当。
