Band gap engineered TiO2 nanoparticles for visible light induced photocatalysis

<div>Visible light-active TiO2 (m-TiO2) nanoparticles were obtained by an electron beam treatment of</div><div>commercial TiO2 (p-TiO2) nanoparticles. The m-TiO2 nanoparticles exhibited a distinct red-shift in the</div><div>UV-visible absorption spectrum and a much narrower band gap (2.85 eV) due to defects as confirmed by</div><div>diffuse reflectance spectroscopy (DRS), photoluminescence (PL), X-ray diffraction, Raman spectroscopy,</div><div>electron paramagnetic resonance, transmission electron microscopy, X-ray photoelectron spectroscopy</div><div>(XPS), electrochemical impedance spectroscopy (EIS) and linear scan voltammetry (LSV). The XPS</div><div>revealed changes in the surface states, composition, Ti4+ to Ti3+ ratio, and oxygen deficiencies in the m-</div><div>TiO2. The valence band XPS, DRS and PL results were carefully examined to understand the band gap</div><div>reduction of m-TiO2. The visible light-responsive enhanced photocatalytic activity of m-TiO2 was</div><div>demonstrated by degrading methylene blue and brilliant blue G. The EIS and LSV in the dark and under</div><div>visible light irradiation further support the visible light-induced photocatalytic activities of the m-TiO2</div><div>due to a decrease in electron transfer resistance and an increase in photocurrent. This study confirms</div><div>that m-TiO2 can be used effectively as a photocatalyst and photoelectrode material owing to its</div><div>enhanced visible light-induced photocatalytic activity.