Surface Area Of Photocatalyst Research Articles

Ammonia photosynthesis under ambient conditions using an efficient nanostructured FeS2/CNT solar-energy-material with water feedstock and nitrogen gas

Through a facile solvothermal route, pyrite (FeS2) semiconductor nanoparticles were synthesized in the absence and presence of carbon nanotube (CNT), and employed as effective, narrow-bandgap, hole-scavenger-free, photocatalyst/solar-energy materials in a water photosplitting setup, to convert N2 molecules into ammonia – a modern/green H-based fuel and agriculturally important chemical. The investigations revealed that the presence of CNT substantially enhances the photocatalyst activity. The superiority of FeS2/CNT nanocomposite energy material was explained in detail in terms of the ability of CNT to increase the photocatalyst surface area and interact with more N2 molecules, boost the absorption of photons and effectually harvest the incident light, retard the recombination of e/h pairs, decrease the system impedance and facilitate the charge transfer process. Based on water-oxidation and proton reduction phenomena occurring upon the photocatalyst surface, the N2-photofixation process was also interpreted from mechanistic/photoelectrochemical/energetic perspective.

A step forward in heterogeneous photocatalysis: Process intensification by using a static mixer as catalyst support

Despite the proven efficiency of heterogeneous photocatalysis using immobilized catalysts, this process lacks integration with the industry due to limitations on mass and photon transfer. The current study aimed to go up against this scenario by applying for the first time a Kenics® static mixer as catalyst support for heterogeneous photocatalysis in tubular reactors. Stainless steel Kenics® static mixers coated with TiO2 or Fe2O3 photocatalyst were assembled in a borosilicate tube coupled to a compound parabolic collector (CPC) and applied to the degradation of the antibiotic oxytetracycline (OTC) in aqueous solution. The use of the Kenics® static mixer provided intense mixing even under laminar flow, and, beyond that, the use of sunlight and a CPC ensured that the entire photocatalyst surface area was receiving front side illumination.Fe2O3 catalyst showed superiority over TiO2 for OTC degradation, exhibiting a pseudo-first-order kinetic constant 79% higher. However, while no TiO2 leaching occurred, up to around 0.7 mg L−1 of total dissolved iron were leachated. Thus, both homogeneous and heterogeneous photo-Fenton reactions may have contributed to the higher OTC degradation by Fe2O3 photocatalysis.The effect of various parameters on the photocatalytic efficiency was assessed: (i) photocatalyst deposition technique, (ii) photocatalyst dosage, (iii) H2O2 concentration, and (iv) number of static mixing elements. Spray coating technique showed superiority over dip coating. OTC degradation was improved by using 50 mL of TiO2 suspension together with 77 mg L−1 of H2O2, and 75 mL of Fe2O3 suspension together with 154 mg L−1 of H2O2. The increase of the number of Kenics® static mixing elements from two to six did not improve the OTC degradation rate. Furthermore, the reusability of both catalysts was proved.

Efficient visible-light photocatalysis of ZIF-derived mesoporous ZnFe2O4/ZnO nanocomposite prepared by a two-step calcination method

Specific surface area of photocatalyst usually has an important influence on its photocatalytic performance. Herein, mesoporous ZnFe2O4/ZnO nanocomposites were successfully fabricated by facile calcination methods using ZnFe2O4/ZIF-8 as the precursor. The structure, morphology, optical and adsorption properties of the as-prepared samples were detailedly characterized, and photocatalytic performances of these samples were mainly evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation (λ > 400nm). The results demonstrated that the ZnFe2O4/ZnO hybrids are of enhanced visible-light photocatalytic performances among all the samples, indicating that the heterojunction structure between ZnFe2O4 and ZnO efficiently inhibited the the recombination of photogenerated electron-hole pairs. Wherein, the ZFO/C6A4 sample prepared via two-step calcination method (600°C in Ar and then 400°C in air ambient) possessed higher visible light photocatalytic activity than the ZFO/A6 sample prepared via one-step calcination (600°C in air ambient). This phenomenon was probably ascribed to the lager pore volume and average pore size of ZFO/C6A4 sample. Moreover, the potential carbon doping in ZnO particles during two-step calcination process was inferred by the XRD analysis, which further facilitated the separation of photogenerated electron-hole pairs in the ZFO/C6A4 sample. On the other hand, the composite sample also exhibited good magnetic recovery property and photochemical stability. These results indicated that the ZnFe2O4/ZnO nanocomposite prepared via two-step calcination method would be quite promising for the degradation of organic pollutants.

Copper and platinum doped titania for photocatalytic reduction of carbon dioxide

The parent TiO2, platinum and copper doped TiO2 photocatalysts with 0.5–2wt. % of Pt, 0.5–2wt. % Cu and 1wt. % Pt combined with 1wt. % Cu were prepared by the sol-gel method. All the prepared photocatalysts were tested for the CO2 photocatalytic reduction in a stirred batch reactor. The main reaction product was methane, however, hydrogen and carbon monoxide were also detected. The textural, (micro)structural, optical and electronic properties of photocatalysts were characterized in detail by low-temperature nitrogen physisorption, X-ray powder diffraction, EDX, HRTEM, X-ray fluorescence, X-ray photon spectroscopy, scanning electron microscope, transmission electron microscope and diffuse reflectance UV–vis spectroscopy. The photoelectrochemical characteristics of the photocatalysts were determined using photoelectric spectrometry. The highest yields of CH4, H2 and CO were achieved in the presence of 2wt. % Cu/TiO2, 0.5 wt. % Cu/TiO2 and pure, amorphous TiO2. Based on the conducted experiments it was suggested that both the amount of chemisorbed oxygen or/and hydroxyl species on the TiO2 surface and specific surface area of photocatalyst highly influence its photocatalytic activity.

Photocatalytic efficiency of Fe2O3/TiO2 for the degradation of typical dyes in textile industries: Effects of calcination temperature and UV-assisted thermal synthesis

The inadequate management practices in industrial textile effluents have a considerable negative impact on the environment and human health due to the indiscriminate release of dyes. Photocatalysis is one of the diverse advance oxidation processes (AOPs) and titanium dioxide (TiO2) is recognized for its high oxidation and reduction power. A composite photocatalyst of Fe2O3/TiO2 is synthesized using different mass ratios of Fe:TiO2 to improve its photoactivity. The composite photocatalyst is calcined at 300–900 °C. Their photocatalytic activity for the degradation of Congo red (CR) and methyl orange (MO) is investigated by total organic carbon (TOC) analysis. The formation and characterization of the as-prepared composite are studied by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). The effect of calcination temperature on the composite Fe2O3/TiO2 photocatalyst is investigated using Fourier transform infrared spectroscopy (FTIR). The photocatalytic activity and the phase conversion are studied by X-ray diffraction (XRD). The specific surface area of photocatalysts at different calcination temperatures is investigated based on Brunauer-Emmett-Teller (BET) surface area analysis. Results show that at an optimum calcination temperature of 300 °C for the photocatalyst preparation, the specific surface area is maximum and the photocatalyst has the highest photoactivity. Thus, the degradation of organic materials reaches 62.0% for MO and 46.8% for CR in the presence of Fe2O3/TiO2 (0.01 w:w Fe:TiO2) calcined at 300 °C with the highest specific surface area (98.73 m2/g). The transformation of TiO2 from anatase to rutile is facilitated by high temperature and high concentration of iron while high crystallization and particle size increase occur. An optimum calcination temperature of 300 °C is found at which the degradation of typical dyes in textile industries is maximum.

A highly efficient pn junction nanocomposite solar-energy-material [nano-photovoltaic] for direct conversion of water molecules to hydrogen solar fuel

Abstract: Besides their application in photovoltaics, semiconductor solar-energy-materials can be directly employed as photocatalysts of hydrogen fuel production using sunlight and water feedstock. In this paper, through a facile hydrothermal route, we synthesized a CuO-ZnO pn junction nanocomposite in the absence and presence of carbon nanotube (CNT), and applied them in a water photosplitting setup to evolve hydrogen gas. The investigation revealed that in the presence of CNT, the photocatalyst performance increases significantly–becomes approximately twice. The superior activity witnessed here for the ternary nanocomposite (CuO-ZnO/CNT) was explained in terms of the ability of CNT to enlarge the photocatalyst surface area, enhance the absorption of photons, and prohibit the recombination of photogenerated e/h pairs. Finally, quantum yield and energy efficiency analyses were performed on both binary and ternary nanocomposite materials as well as on their semiconductor components, and the results were discussed in detail from physicochemical viewpoint.

Exploration of silver decoration concentration to enhance photocatalytic efficiency of titanium dioxide photocatalysts

Ag decoration on TiO2 is favorable to absorption of visible light and wider absorption range. Ag nanoparticles playing the role of electron receivers on TiO2 surface enhance photodegradation. However, excess Ag nanoparticles caused reduced specific surface area of photocatalysts and increased probability of charge recombination, resulting in lower photocatalytic efficiency. In this study, the influence of various Ag decoration concentrations on photocatalytic activity was investigated. Surface treatment by nitric acid after Ag decoration was performed to avoid excessive Ag deposition. The extent of Ag elimination and its impacts on photocatalytic activity were also explored. An optimum Ag content in the photocatalyst was achieved and photocatalytic efficiency was obviously improved. It was found that the number of calcination times affected the crystallinity and stability of photocatalysts. Better photocatalytic efficiency could be obtained after twice calcinations.

ZnO nanorods grown on ultrathin ZnO seed layers: Application in water treatment

Ultrathin and ultrasmooth ZnO films, grown by atomic layer deposition (ALD), are used as seed layers for chemical bath deposition (CBD), to synthesize dense and long ZnO nanorod arrays. The enhanced photocatalytic capability of the sintesized materials reveals their potentiality for wastewater treatment. The thickness of the ALD seed layers triggers the final ZnO nanorods height and density and, accordingly, the overall photocatalyst surface area. In particular, the thinnest ALD ZnO layer promotes the grow of highly oriented and dense ZnO nanorod arrays, which are able to efficiently degradate methylene blue dye and phenols under UV light irradiation. These heterogeneous photocatalysts are stable to aging effects, can be easily removed from water without any filtration process and can be efficiently reused for multiple degradation cycles.

Review of photocatalytic water-splitting methods for sustainable hydrogen production

This paper examines photocatalytic hydrogen production as a clean energy solution to address challenges of climate change and environmental sustainability. Advantages and disadvantages of various hydrogen production methods, with a particular emphasis on photocatalytic hydrogen production, are discussed in this paper. Social, environmental and economic aspects are taken into account while assessing selected production methods and types of photocatalysts. In the first part of this paper, various hydrogen production options are introduced and comparatively assessed. Then, solar-based hydrogen production options are examined in a more detailed manner along with a comparative performance assessment. Next, photocatalytic hydrogen production options are introduced, photocatalysis mechanisms and principles are discussed and the main groups of photocatalysts, namely titanium oxide, cadmium sulfide, zinc oxide/sulfide and other metal oxide-based photocatalyst groups, are introduced. After discussing recycling issues of photocatalysts, a comparative performance assessment is conducted based on hydrogen production processes (both per mass and surface area of photocatalysts), band gaps and quantum yields. The results show that among individual photocatalysts, on average, Au–CdS has the best performance when band gap, quantum yield and hydrogen production rates are considered. From this perspective, TiO2–ZnO has the poorest performance. Among the photocatalyst groups, cadmium sulfides have the best average performance, while other metal oxides show the poorest rankings, on average. Copyright © 2016 John Wiley & Sons, Ltd.

Enhancing the photocatalytic activity of CdS nanorods for selective oxidation of benzyl alcohol by coating amorphous TiO2 shell layer

One dimension (1D) core–shell structural CdS@TiO2 was fabricated by a modified sol–gel method. The thickness of amorphous TiO2 (a-TiO2) layer was adjusted by changing the amount of ammonia. Although a-TiO2 shell layer diminishes the visible light absorption in a certain extent, it largely increases the surface area of photocatalyst and effectively promotes the separation rate of photogenerated electron–hole pairs. It was revealed that a-TiO2 shell layer can effectively enhance the photocatalytic activity of CdS NRs for benzyl alcohol (BA) to benzaldehyde (BAD) transformation. Moreover, the core–shell structural CdS@a-TiO2 showed high stability and reusability for the selective oxidation of BA.

Effect of TiO2 polymorph and alcohol sacrificial agent on the activity of Au/TiO2 photocatalysts for H2 production in alcohol–water mixtures

This study compares the performance of 5 different Au/TiO2 photocatalysts for H2 production in alcohol–water mixtures under UV excitation, placing particular emphasis on the role of the TiO2 support and alcohol sacrificial reagent. 1.5wt.% Au/TiO2 photocatalysts were prepared by the deposition–precipitation with urea method, using P25 TiO2 (85% anatase and 15% rutile, 49m2g−1), sol–gel anatase (39m2g−1), hydrothermally synthesised anatase (115m2g−1), commercial brookite (33m2g−1) and hydrothermally synthesised rutile (29m2g−1) as supports. UV–Vis, TEM, XRD, XPS and Au L3-edge EXAFS characterisation studies confirmed the presence of gold nanoparticles of mean size 5–10nm on all the Au/TiO2 photocatalysts, which generated intense localised surface plasmon resonances (LSPRs) centred between 560 and 590nm. Gold nanoparticle deposition suppressed electron–hole pair recombination in each TiO2 support following UV excitation, and created cathodic sites on TiO2 for H2 evolution. Photocatalytic H2 production tests were conducted in water, methanol–water, ethanol–water, ethylene glycol–water and glycerol–water mixtures (alcohol concentration 10vol.%) at a UV flux of 6.5mWcm−2. H2 production rates decreased in the order Au/P25>Au/anatase SG≈Au/brookite>Au/anatase HT≫Au/rutile HT when the rates were normalised against photocatalyst surface area. For each Au/TiO2 photocatalyst, the rates decreased in the order glycerol>ethylene glycol>methanol>ethanol. Good correlations were established between H2 production rates and the number of hydroxyl groups, polarity and relative hole scavenging ability of the alcohols. Results improve knowledge about the role of sacrificial reagents in photocatalytic hydrogen production.

Photocatalytic H<sub>2</sub> Production Using Semiconductor Nanomaterials via Water Splitting – An Overview

Heterogeneous semiconductor based photocatalytic hydrogen (H2) production by water splitting is one of the widely recognized promising sustainable technologies to deliver clean energy for future energy demands. The present review article mainly focus on the overview of principle of water splitting, different semiconductor nanomaterials used for photocatalytic water splitting in the presence of UV and solar light irradiation, role of sacrificial reagents, simultaneous degradation of pollutants and H2 production reaction, strategy for development of efficient photocatalyst for H2 production. Further the flaws associated with present photocatalytic system like recombination rate of electron–hole pairs, low visible-light response, use of hazardous irradiation sources and surface area of photocatalyst etc. has also been discussed. Recently the use of energy efficient light emitting diodes (LEDs) as an irradiation source for H2 production is highly attracted due to its unique characteristics. Recent literature on LED source based photocatalytic system for H2 production has also been summarized and highlighted. At last, the future prospects and challenges towards the designing of better photocatalytic system for H2 production have also been discussed. From the literature survey, it is concluded that construction of efficient photocatalytic system for simultaneous degradation of pollutants and H2 production under energy efficient irradiation source offer clean and simple system for solving the futuristic environmental concerns and energy crisis.

Titanium Dioxide Supported on Different Porous Materials as Photocatalyst for the Degradation of Methyl Green in Wastewaters

TiO2nanoparticles were immobilized on two porous materials used as catalyst supports, namely, activated carbon (AC) and natural clay (NC), through an impregnation process using TiO2(P25) as precursor. The so-prepared composite materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), and nitrogen physisorption, that is, Brunauer-Emmett-Teller (BET) surface area determination. SEM and TEM observation evidenced that TiO2was deposited on AC and NC surface. XRD results confirmed that TiO2existed in a mixture of anatase and rutile phases. The specific surface area of photocatalysts decreased drastically in comparison with the original materials. The photocatalytic activity of these materials was assayed in the oxidation of Methyl Green (MG) dye in aqueous medium under UV irradiation. TiO2/AC exhibited higher photocatalytic oxidation activity than TiO2at neutral pH. Total mineralization of MG was confirmed by means of COD analysis, pointing to these materials as an efficient, cost-effective, and environment friendly alternative for water treatment.

Template‐Free Synthesis of Hollow Porous Strontium Titanate Particles

Strontium titanate (SrTiO3) is a potential photocatalyst of H2 evolution for providing green energy. One of the main strategies for increasing the efficiency of H2 evolution is to increase the surface area of photocatalysts. In this study, spray pyrolysis was used because of its superior flexibility in morphological control. Three typical reactants, nitric acid, acetic acid, and citric acid, were added to Sr and Ti precursors to form various morphological SrTiO3 powders. The SrTiO3 powders were investigated by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, focused ion beam technique, and the Brunauer–Emmett–Teller (BET) method to determine the phase composition, surface morphology, geometry, inner structure, and specific surface area, respectively. Four main morphologies of SrTiO3 particles, namely, porous, concave porous, wrinkled spherical, and hollow porous structures, were obtained. Among these powders, SrTiO3 particles prepared with citric acid had the highest surface area (46.9 m2/g) because of their hollow porous structure. Finally, the formation mechanisms of these four distinct SrTiO3 morphologies are discussed.

Efficient Visible-Light-Driven Photocatalytic Degradation with Bi2O3 Coupling Silica Doped TiO2

A new TiO2-based visible light photocatalyst (Bi2O3/Si–TiO2) was synthesized by both Bi2O3 coupling and Si doping via a two-step method. The structural, morphological, light absorption, and photocatalytic properties of as-prepared samples were studied using various spectroscopic and analytical techniques. The results showed that Bi2O3/Si–TiO2 catalysts held an anatase phase and possessed high thermal stability. The doped Si was woven into the lattice of TiO2, and its content had a significant effect on the surface area and the crystal size of Bi2O3/Si–TiO2. The introduced Bi species mainly existed as oxides on the surface of TiO2 particles, and the Bi2O3 photosensitization extended the light absorption into the visible region. Bi2O3 coupling also favored the separation and transfer of photoinduced charge carriers to inhibit their recombination and Si doping enlarged the surface area of photocatalysts. Compared to bare TiO2, Bi2O3/TiO2, and Si–TiO2, Bi2O3/Si–TiO2 samples showed better activities for the degradation of methyl orange (MO) and bisphenol A (BPA) under visible light irradiation (λ > 420 nm). The highest activity was observed for 1.0% Bi2O3/15% Si–TiO2 calcined at 500 °C. The superior performance was ascribed to the high surface area, the ability to absorb visible light, and the efficient charge separation associated with the synergetic effects of appropriate amounts of Si and Bi in the prepared samples. The adsorbed hydroxyl radicals (•OH) were also found to be the most reactive species in the photocatalytic degradation.

Ag-doped ZnO nanorods coated metal wire meshes as hierarchical photocatalysts with high visible-light driven photoactivity and photostability

Ag-doped ZnO nanorods were grown on stainless-steel wire meshes to fabricate the hierarchical photocatalysts with excellent visible light driven activity and anti-photocorrosion property. Effects of Ag doping and the surface structure on the surface chemistry, surface wetting properties, absorption band shift, photoelectrochemical response, and photocatalytic decolorization properties of the hierarchical photocatalysts, together with the stability of photocatalytic activity for recycled photocatalysts were investigated. Ag doping leads to red-shift in the absorption band and increased visible light absorption. Nanorods coated wire meshes hierarchical structure not only increases the surface area of photocatalysts but also makes the surface hydrophilic. The photocatalytic activity enhancement and reduced photocorrosion can be achieved because of increased surface area, enhanced hydrophilicity, and the interaction between the metal wire/ZnO and Ag/ZnO heterostructure interface which can improve the charge separation of photogenerated charge carriers.

Synthesis, Surface Characterization and Photocatalytic Activity of TiO2 Supported on Almond Shell Activated Carbon

Three types of photocatalysts were synthesized by metal organic chemical vapor deposition and impregnation methods using the almond shell activated carbon as support. These photocatalysts denoted by (TiO2/ASAC (V), TiO2/ASAC (I1) and TiO2/ASAC (I2)) were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and nitrogen adsorption–desorption isotherms. SEM observation shows that TiO2 was deposited on activated carbon surface. XRD results confirm that TiO2 existed in a mixture of anatase and rutile phases. The DRS spectra show the characteristic absorption edge of TiO2 at approximate 380 nm corresponding to the optical band gap of 3.26 eV. Besides, FTIR spectrum indicated the presence of (Ti–O) groups. The specific surface area of photocatalysts decreased drastically in comparison with the original activated carbon. The catalysts were very efficient for the photodegradation of total organic carbon (TOC) from industrial phosphoric acid solution under UV irradiation. The kinetics of photocatalytic TOC degradation was found to follow a pseudo-first-order model. The prepared TiO2/ASAC showed high photoactivity for the photodegradation of TOC in the following order: TiO2/ASAC (V) > TiO2/ASAC (I1) > TiO2/ASAC (I2) > ASAC > TiO2 (P25).

Optimization Studies of Photocatalytic Tungsten-Doped Titania Coatings Deposited by Reactive Magnetron Co-Sputtering

In this article we investigate the structural and photocatalytic properties of W-doped titanium dioxide coatings. TiO2-W thin films were deposited onto glass slides by reactive magnetron co-sputtering. The properties of the films were analyzed using such techniques as XRD, Raman spectroscopy, EDX, TEM, and surface profilometry. The photocatalytic properties of the coatings were assessed using the methylene blue (MB) degradation test under UV and fluorescent light sources. The methylene blue decomposition experiments showed that, at the optimum dopant concentration of tungsten, the photocatalytic activity can be improved by a factor of 6, compared to undoped titania. For the coatings discussed within this work, the optimum dopant concentration was determined to be 5.89 at.% of W. The results indicated that tungsten doping at this level extends the lifetime of the photogenerated charge carriers and significantly increases the photocatalyst surface area.

The impeding effect of dissolved oxygen on the photocatalytic reduction of [PdCln(H2O)4−n]2−n (n = 0–4) complexes employing different TiO2 photocatalysts in the absence of an added sacrificial reducing agent

The photocatalytic reduction of chloro-aqua palladium(II) complexes, [PdCln(H2O)4−n]2−n (n=0–4), as a means of palladium metal recovery and waste water purification, was investigated employing four different titanium dioxide samples in a batch reactor. These suspensions were subjected to UV irradiation in the absence of an added sacrificial reducing agent (SRA) for oxygen purged, air equilibrated and nitrogen purged solutions. A commercial Degussa P25 titanium dioxide powder (DP25) was taken as standard photocatalyst and compared to three other commercial titanium dioxide powders, namely Tioxide A-HR (AHR), Sigma–Aldrich Anatase (SAA) and Sigma–Aldrich Rutile (SAR). The highest rate of photocatalytic reduction was observed for the lower chlorinated Pd(II) complexes in nitrogen, i.e. oxygen depleted solutions, at constant temperature, photocatalyst load, pH and ionic strength on all four photocatalysts. Sigma–Aldrich Rutile (SAR) was the only photocatalyst capable of reducing the highly chloride coordinated [PdCl4]2− complex, in the absence of an added organic SRA, in air equilibrated and nitrogen purged solutions. The presence of dissolved oxygen was found to be detrimental to the photocatalytic reduction of highly chloride coordinated chloro-aqua palladium(II) complexes. The effect of the structure of the complex as well as the photocatalyst surface area, crystal phase composition, aggregate particle size and band gap energy was explored in an effort to elucidate the observed differences in behaviour of the photocatalysts.

Development of a doped titania immobilised thin film multi tubular photoreactor

This paper describes a novel doped titania immobilised thin film multi tubular photoreactor which has been developed for use with liquid, vapour or gas phase media. In designing photocatalytic reactors measuring active surface area of photocatalyst within the unit is one of the critical design parameters. This dictate greatly limits the applicability of any semi-conductor photocatalyst in industrial applications, as a large surface area equates to a powder catalyst. This demonstration of a thin film coating, doped with a rare earth element, novel photoreactor design produces a photocatalytic degradation of a model pollutant (methyl orange) which displayed a comparable degradation achieved with P25 TiO2. The use of lanthanide doping is reported here in the titania sol gel as it is thought to increase the electron hole separation therefore widening the potential useful wavelengths within the electromagnetic spectrum. Increasing doping from 0.5% to 1.0% increased photocatalytic degradation by ∼17% under visible irradiation. A linear relationship has been seen between increasing reactor volume and degradation which would not normally be observed in a typical suspended reactor system.