@article{chin_grant_ollis_2009, title={Quantitative photocatalyzed soot oxidation on titanium dioxide}, volume={87}, ISSN={["1873-3883"]}, DOI={10.1016/j.apcatb.2008.09.020}, abstractNote={Abstract We report here the titanium dioxide (TiO 2 ) photocatalyzed oxidation of deposited hurricane lamp soot. Sol–gel derived TiO 2 was coated on quartz crystal microbalance (QCM) elements. Characterization by spectroscopic ellipsometry ( SE ) and atomic force microscopy (AFM) revealed low surface roughness of 0–17%, and SE showed a linear variation of the TiO 2 thickness versus the number of sol–gel spin coats. Soot was deposited on the calcined TiO 2 film using an analytical rotor passing through a hurricane lamp flame, and subsequently irradiated with near-UV light. Varying the soot mass on the TiO 2 -coated QCM crystals revealed behaviors over 20,000 min ranging from total soot destruction of a single pass soot layer to minimal oxidation of an eight pass soot layer, the latter caused by soot screening of the incident UV light. A series/parallel reaction mechanism [P. Chin, G.W. Roberts, D.F. Ollis, Industrial & Engineering Chemistry Research 46 (2007) 7598] developed to describe previous literature data on TiO 2 -catalyzed soot photooxidation was successfully employed to capture the longer time changes in presumably graphitic soot mass as a function of UV illumination time from 1000 to 20,000 min and of soot layer thickness. Short time soot mass loss is attributed to oxidation of organic carbons deposited on the graphitic soot components. This kinetic model can be used to predict the rate of TiO 2 -catalyzed soot destruction as a function of near-UV illumination time and initial soot layer thickness.}, number={3-4}, journal={APPLIED CATALYSIS B-ENVIRONMENTAL}, author={Chin, Paul and Grant, Christine S. and Ollis, David F.}, year={2009}, month={Apr}, pages={220–229} }
 @article{chin_ollis_2008, title={Design approaches for a cycling adsorbent/photocatalyst system for moor air purification: Formaldehyde example}, volume={58}, ISSN={["1047-3289"]}, DOI={10.3155/1047-3289.58.4.494}, abstractNote={Abstract A kinetic model for a cycling adsorbent/photocatalyst combination for formaldehyde removal in indoor air (Chin et al. J. Catalysis 2006, 237, 29-37) was previously developed in our lab, demonstrating agreement with lab-scale batch operation data of other researchers (Shiraishi et al. Chem. Engineer. Sci. 2003, 58, 929-934). Model parameters evaluated included adsorption equilibrium and rate constants for the adsorbent (activated carbon) honeycomb rotor, and catalytic rate constant for pseudo-first-order formaldehyde destruction in the titanium dioxide photoreactor. This paper explores design consequences for this novel system. In particular, the batch parameter values are used to model both adsorbent and photocatalyst behavior for continuous operation in typical residential home challenges. Design variables, including realistic make-up air fraction, adsorbent honeycomb rotation speed, and formaldehyde source emission rate, are considered to evaluate the ability of the system to achieve World Health Organization pollutant guidelines. In all circumstances, the size of the required rotating adsorbent bed and photoreactor for single-stage operation and the resultant formaldehyde concentration in the home are calculated. The ability of how well such a system might be accommodated within the typical dimensions of commercial ventilation ducts is also considered.}, number={4}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Chin, Paul and Ollis, David F.}, year={2008}, month={Apr}, pages={494–501} }
 @article{chin_ollis_2007, title={Decolorization of organic dyes on Pilkington Activ (TM) photocatalytic glass}, volume={123}, ISSN={["0920-5861"]}, DOI={10.1016/j.cattod.2007.01.069}, abstractNote={The air–solid photocatalytic degradation of organic dye films Acid Blue 9 (AB9) and Reactive Black 5 (RBk5) is studied on Pilkington Activ™ glass. The Activ™ glass comprises of a colorless TiO2 layer deposited on clear glass. The Activ™ glass is characterized using atomic force microscopy (AFM) and X-ray diffraction (XRD). Using AFM, the TiO2 average agglomerate particle size is 95 nm, with an apparent TiO2 thickness of 12 nm. The XRD results indicate the anatase phase of TiO2, with a calculated crystallite size of 18 nm. Dyes AB9 and RBk5 are deposited in a liquid film and dried on the Activ™ glass to test for photodecolorization in air, using eight UVA blacklight-blue fluorescent lamps with an average UVA irradiance of 1.4 mW/cm2. A novel horizontal coat method is used for dye deposition, minimizing the amount of solution used while forming a fairly uniform dye layer. About 35–75 monolayers of dye are placed on the Activ™ glass, with a covered area of 7–10 cm2. Dye degradation is observed visually and via UV–vis spectroscopy. The kinetics of photodecolorization satisfactorily fit a two-step series reaction model, indicating that the dye degrades to a single colored intermediate compound before reaching its final colorless product(s). Each reaction step follows a simple irreversible first-order reaction rate form. The average k1 is 0.017 and 0.021 min−1 for AB9 and RBk5, respectively, and the corresponding average k2 is 2.0 × 10−3 and 1.5 × 10−3 min−1. Variable light intensity experiments reveal a p = 0.44 ± 0.02 exponent dependency of initial decolorization rate on the UV irradiance. Solar experiments are conducted outdoors with an average temperature, water vapor density, and UVA irradiance of 30.8 °C, 6.4 g water/m3 dry air, and 1.5 mW/cm2, respectively. For AB9, the average solar k1 is 0.041 min−1 and k2 is 5.7 × 10−3 min−1.}, number={1-4}, journal={CATALYSIS TODAY}, author={Chin, Paul and Ollis, David F.}, year={2007}, month={May}, pages={177–188} }
 @article{chin_roberts_ollis_2007, title={Kinetic Modeling of photocatalyzed soot oxidation on titanium dioxide thin films}, volume={46}, ISSN={["0888-5885"]}, DOI={10.1021/ie070083t}, abstractNote={Recent research [Mills et al. Chemosphere 2006, 64, 1032−1035; Lee and Choi J. Phys. Chem. B 2002, 106, 11818−11822] has demonstrated photocatalytic oxidation of “soot” by titanium dioxide thin films. However, little attention has been paid to developing kinetic models of photocatalyzed soot destruction. We develop here a series/parallel kinetic model for soot oxidation and use it to analyze the CO2 data of Mills et al. and the mass loss data of Lee and Choi. The model assumes two oxidation pathways:  a single step yielding CO2 directly and a serial sequence through a solid intermediate species, which is subsequently oxidized to CO2. We extend this simple model to include variable O2 partial pressure, which is used to evaluate the initial CO2 data of Lee and Choi. These models fit the experimental CO2 data of Mills et al. and Lee and Choi well. The simple kinetic model also describes the mass loss data of Lee and Choi for the front mode of sample irradiation.}, number={23}, journal={INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH}, author={Chin, Paul and Roberts, George W. and Ollis, David F.}, year={2007}, month={Nov}, pages={7598–7604} }
 @article{chin_yang_ollis_2006, title={Formaldehyde removal from air via a rotating adsorbent combined with a photocatalyst reactor: Kinetic modeling}, volume={237}, ISSN={["1090-2694"]}, DOI={10.1016/j.jcat.2005.10.013}, abstractNote={A novel rotating honeycomb adsorbent coupled with a photocatalytic reactor demonstrated by Shiraishi et al. is modeled here. In operation, the air pollutant formaldehyde was adsorbed from a simulated room (10 m3) onto a slowly rotating honeycomb, which then passed slowly through a small chamber (0.09 m3) in which locally recirculated heated air desorbed the formaldehyde and carried it through a photocatalytic reactor, which oxidized the desorbed material. The regenerated rotor-adsorbent then rotated back into the airtight chamber. This system was modeled at steady states and transient states to determine adsorption, desorption, and photocatalyst pseudo-first-order rate constants at the appropriate temperatures (ambient temperature for adsorption, 120–180 °C for desorption and photocatalysis). Intensity-corrected values for the photocatalytic rate constant kcat (cm2/(mW s)) deduced from fitting our model to the data of Shiraishi et al. were in good agreement with those calculated from five literature reports for formaldehyde photocatalytic destruction.}, number={1}, journal={JOURNAL OF CATALYSIS}, author={Chin, P and Yang, LP and Ollis, DF}, year={2006}, month={Jan}, pages={29–37} }
 @article{chin_sun_roberts_spivey_2006, title={Preferential oxidation of carbon monoxide with iron-promoted platinum catalysts supported on metal foams}, volume={302}, ISSN={["1873-3875"]}, DOI={10.1016/j.apcata.2005.11.030}, abstractNote={A series of 5 wt% Pt/0.5 wt% Fe/γ-Al2O3 catalysts supported on metal foams of different geometries were synthesized and tested for preferential oxidation of a low CO concentration in the presence of a high H2 concentration. The catalysts were tested in a fixed bed adiabatic reactor at a total pressure of 0.2 MPa (absolute) to simulate fuel processor operating pressure. The inlet temperature was varied from 80 °C to 170 °C, and the gas hourly space velocity ranged from 5000 h−1 to 45,000 h−1. The inlet gas composition to the reactor reproduced that of the effluent stream from the water-gas-shift reactor in a typical fuel processor: H2 42%, CO2 9%, H2O 12%, CO 1.0%, O2 0.5–1.0%, and N2 35–35.5%. The geometry of a foam is characterized by the volume fraction of solid material (cell density) and by the number of pores per inch. The catalysts with lower cell densities generally exhibited higher CO conversions and selectivities. Under most operating conditions, the CO conversion and selectivity of the best metal foam catalysts were comparable to those of a 400 cells per square inch, ceramic straight-channel monolith with the same nominal catalyst loading. Both the reverse water-gas-shift (r-WGS) reaction and transport resistances affected the performance of these catalysts. Under adiabatic conditions, the r-WGS reaction made it impossible to achieve low outlet CO concentrations. The effects of space velocity and linear velocity were studied independently using various catalyst lengths and volumetric gas flow rates. At a constant space velocity, the CO conversion increased with higher linear velocities, suggesting a significant mass transfer resistance between the bulk gas and the catalyst surface.}, number={1}, journal={APPLIED CATALYSIS A-GENERAL}, author={Chin, P and Sun, XL and Roberts, GW and Spivey, JJ}, year={2006}, month={Mar}, pages={22–31} }
 @article{roberts_chin_sun_spivey_2003, title={Preferential oxidation of carbon monoxide with Pt/Fe monolithic catalysts: interactions between external transport and the reverse water-gas-shift reaction}, volume={46}, ISSN={["1873-3883"]}, DOI={10.1016/j.apcatb.2003.07.002}, abstractNote={A series of Pt/Al2O3 catalysts, promoted with Fe and supported on 400 cpsi (cells per square inch) (62 cells/cm2) ceramic straight-channel monoliths, was synthesized and evaluated for preferential oxidation (PROX) of a low concentration of CO in the presence of a high concentration of H2. These catalysts were evaluated in an adiabatic reactor at a total pressure of 0.20 mPa inlet temperatures of 80–170 °C, and a space velocity of 30,000 h−1. The inlet gas composition was—H2: 42%, CO2: 9%, H2O: 12%, CO: 0–1.0%, O2: 0–1.0%, with N2 as the balance. For a catalyst containing 5 wt.% Pt in the washcoat, the carbon monoxide and oxygen conversions increased as the iron concentration in the washcoat was increased up to about 0.5 wt.% Fe. The reverse water-gas-shift (r-WGS) reaction played an important role in determining the outlet CO concentration. A catalyst with 1.6 g/in.3 (0.098 g/cm3) of an alumina washcoat containing 5 wt.% Pt/Al2O3 promoted with 0.5 wt.% Fe was selected for detailed investigation. The effects of both space velocity and linear velocity were studied. External transport was a significant resistance with this catalyst, at the above experimental conditions. The external resistances to heat and mass transfer, coupled with the effect of the r-WGS reaction, reduced the observed CO conversion and selectivity.}, number={3}, journal={APPLIED CATALYSIS B-ENVIRONMENTAL}, author={Roberts, GW and Chin, P and Sun, XL and Spivey, JJ}, year={2003}, month={Nov}, pages={601–611} }