Photocatalytic odor abatement by platinized TiO2 under optically transmitted LED–UV light

Abstract

Combined use of platinized titania and light emitting diode (LED) ultraviolet (UV) illumination was explored for photocatalytic odor abatement with carbon disulfide (CS2) as model odorant. Noble metal deposition on anatase titanium dioxide (TiO2) surface was achieved by UV assisted photoreduction of platinum (Pt). Solid-state and elemental analyses show that surface platinized (Pt/TiO2) and bare (TiO2) titania, while of comparable bulk structural properties, differ in light absorption and surface characteristics as a result of the photodeposited Pt. The effect of distance and collimation was modeled to predict the impact of position of UV source and collimation on UV radiation intensity and distribution on photocatalyst surface. Increased radiation intensity due to minimized divergence with collimated LED–UV has improved output beam intensity, resulting in enhanced photoreaction rates regardless of photocatalyst used. Fitting of batch experimental data into classical Langmuir–Hinshelwood (L–H) kinetic model yielded higher model parameter values with Pt/TiO2 than TiO2 as well as the calcined counterparts. Lower number of surface OH groups and better charge carrier separation in calcined and/or Pt surface treated titania were proposed as main factors underpinning enhanced reaction rates and photonic efficiencies. Data fitting into a pseudo-steady-state L–H kinetic model has returned higher optimized fit parameter values with Pt/TiO2 than TiO2 while showing a nonlinear power law relationship between irradiation intensity and reaction rate. Results of fluorescence excitation-emission (EEM) spectroscopy and infrared (IR) thermography corroborate the occurrence of localized surface plasmon resonance (LSPR) effects such as subdued fluorescence and localized heating. By employing plasmonic photocatalysts and innovative delivery of photoradiation, this study has presented a case of a straightforward approach to environmental odor abatement based on affordable and widely available UV–LEDs and titania support.