posted on 2024-02-18, 16:29authored byLi-Sha Zhang, Xu-Sheng Cao, Yefeng Yang, Zhizhen Ye, Jin-Ming Wu
To
develop versatile photocatalysts for efficient degradation of
distinct organic pollutants in water is a continuous pursuit in environment
remediation. Herein, we directly oxidize Ti3C2 MXene with hydrogen peroxide to produce C-doped anatase TiO2 nanowires with aggregates maintaining a layered architecture
of the MXene. The Ti3C2 MXene provides a titanium
source for TiO2, a carbon source for in situ C-doping,
and templates for nanowire aggregates. Under UV light illumination,
the optimized Ti3C2/TiO2 exhibits
a reaction rate constant 1.5 times that of the benchmark P25 TiO2 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 Ti3C2 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 Ti3C2/TiO2 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 TiO2 toward photodegradations for typical
persistent organic pollutants of phenol, dye molecule of rhodamine
B, antibiotic of tetracycline, pharmaceutical wastewater of ofloxacin,
and pesticide of N,N-dimethylformamide, when evaluated
in total organic carbon removal.