Visible light degradation of methylene blue from water by triangle Au@TiO2 mesoporous catalyst
TiO2-coated triangle Au with a core-shell structure(Au@TiO2)was synthesized using the sol-gel method.After hydrothermal crystallization,the particle size expanded to 300 nm with crystallization of the shell TiO2 into a mesoporous anatase phase,while the morphology of the triangle Au particle remained unchanged.The structure and properties of the samples were characterized using powder X-ray diffraction(PXRD),ξ potential,high-resolution transmission electron microscopy(HRTEM),thermogravimetric analysis(TGA),photoluminescence(PL)spectrosco-py,photocurrent(i-t)measurements,and methylene blue(MB)photodegradation tests.The results revealed that the photocatalytic degradation rate of crystallized triangle Au@TiO2 was significantly higher than that of the amorphous material.Specifically,1 mg·mL-1 Au@c-TiO2 achieved complete degradation of 60 mg·L-1 MB after one hour of visi-ble light irradiation.An electron paramagnetic resonance(EPR)experiment was conducted,indicating that·O2-and ·OH are the active species responsible for the degradation process.By combining experimental results with finite-difference time-domain(FDTD)analysis,we proposed a mechanism for the photodegradation process.
photodegradationTiO2triangle Au particlevisible light
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