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Although the intrinsic properties of biocatalytic nanomaterials have led to their increasing importance for biomedical applications, their applicability has been hindered by the disadvantages of (1) environmentally deleterious synthesis procedures, (2) non-biocompatibility of conventional surface functionalising agents, (3) lack of stealth properties, and (4) blockage of biocatalytically active surface sites during synthesis, functionalisation, and application. The present work reports a new green stealth engineering strategy, using environmentally-friendly natural materials green synthesis technique, and stimuli-responsive molecules for the development of biocompatible ceria-based nanocatalysts with lifetime biocatalytic properties. This green and stealth technique has the advantages of being an integrated, one-pot, room-temperature synthesis and surface-modification method involving surfactant-free precipitation, aqueous silanisation, and metal-free O-PET-ATRP surface functionalisation approach. The surface functionalisation represents a stealth and targeted-design approach that leverages a zwitterionic charge-switchable glycopolymeric stealth coating that serves the four functions of being (1) biologically benign, (2) plasma-protein-repulsive in the physiological environment, (3) charge-switchable between physiological environment and tumour microenvironment, and (4) target-specific in the tumour microenvironment. Critically, lifetime catalytic activity is engineered through the avoidance of adsorption of the functionalising and processing species on lattice sites instead of active sites. These processes were monitored by various analytical techniques in order to elucidate the mechanisms of action of the nanoceria while overcoming environmental, processing, and physiological barriers in nanoceria. The outcomes of this new green and stealth engineering strategy provide lifetime retention of nanoceria’s surface-active-sites, thereby optimising the catalytic redox activity in the physiological environment of pH 7.4 (antioxidant) and tumour microenvironment pH of 6.2 (prooxidant) for neuroblastoma and other therapies. Importantly, this novel approach in the design and engineering of new materials with optimal performance has the potential to enable widespread applicability in the biomedical field.

The present work reports data for TiO2 thin films spin coated on unpolished fused silica (FS) and unpolished (001) rutile annealed at 200°, 350°, 450°, and 550 °C for 8 h in air. Characterization/testing consisted of glancing-angle X-ray diffraction, laser Raman microspectroscopy, atomic force microscopy, UV–Vis spectrophotometry, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, transmission electron microscopy, and methylene blue (MB) photodegradation. The recrystallization depended on the type of substrate, where FS substrates yielded Si-contaminated anatase films of limited crystallinity (amorphous at 200 °C) and thickness ~160–200 nm while the rutile substrates resulted in well crystallized epitaxial films of ~200–300 nm thickness. The Si grain boundary diffusion coefficients were 4.59 × 10−19 m2s (200 °C) and 5.00 × 10−19 m2s (550 °C). This diffusion mechanism was supported by the XPS data before and after MB aqueous solution testing, which suggested that Si contamination was on the grain boundaries and was leached during testing. The thickness of all films increased slightly as the annealing temperature increased, which resulted from grain rearrangement and growth. The optical transmissions of all films were low and the reflectances higher, which resulted from the roughness and unevenness of the films. The optical indirect band gaps (Eg) from transmission and reflectance spectrophotometries decreased for the anatase films but increased for the rutile films with increasing annealing temperature. These trends reflect the dominance of competing mechanisms, where recrystallization and Eg decrease are dominant for anatase but void formation and Eg increase are dominant for rutile. The photocatalytic performances of the anatase films were superior to those of the rutile films. The performances corresponded to the annealing temperatures and so were linked directly to the crystallinity and, to a lesser extent, the surface area (reflected by the roughness and unevenness) since the other factors examined were inconsistent with the performance data.

Sn-doped anatase hollow spheres were fabricated using a template method involving polystyrene spheres as core and anatase coating as shell. The synthesis route included the preparation of PS spheres, followed by their coating by Sn-doped TiO 2 sol-gel precursor and subsequent removal of the PS cores by pyrolysis and recrystallization at 500 °C for 2 h. The observation of minor amounts of rutile suggests that Sn promotes the anatase → rutile phase transformation. At doping levels of ≤ 1.0 mol% Sn, the unsaturated solubility and increasing defect densities enhanced nucleation. At 1.0–2.0 mol% Sn, the solubility remained unsaturated but increasing Sn incorporation reduced crystallinity owing to lattice deformation and partial amorphization. At 2.0–3.0 mol% Sn, solid solution saturation occurred, resulting in excess dopant precipitation, leading to grain boundary pinning and partial blockage of surface-active sites. Ionic radii, thermodynamic, phase equilibria, intervalence charge transfer, and defect chemistry considerations suggest that Sn 4+ exhibits substitutional solid solubility in the TiO 2 lattice. The photocatalytic performance was in the order 1.0 > 1.2 > 1.5 ≈ 0.7 > 2.0 > 0.0 > 3.0 mol% Sn. This ranking is consistent with the dominant role of crystallinity such that, at ≤ 1.0 mol% Sn, the performance increased owing to enhanced nucleation from low defect density and increasing crystallinity while, at 1.0–2.0 mol% Sn, the performance decreased from increased lattice strain and effective partial amorphization, and, at 2.0–3.0 mol% Sn, it decreased from maximal lattice strain and blockage of active sites.

There is growing interest in reducing the use of ordinary Portland cement (OPC) owing to its high energy consumption and CO2 emissions. An environmentally-friendly alternative is the use of geopolymers, which can potentially reduce direct CO2 emissions through the appropriate choice of raw materials, mix design, and curing regimes. In this regard geopolymer mortars are also realistic candidates for the replacement of OPC mortars in nuclear waste immobilisation applications as they provide a more durable incorporation matrix as well as suppressing the formation of radiolytic hydrogen. The advantages of geopolymers over OPC for nuclear waste immobilisation include i) lower water content as alkaline activator is the main component that drives geopolymerisation, ii) higher thermal stability (

Flat TiO2 thin films were dip coated on contact lens polymer substrates (fluorinated ethylene propylene copolymer, FEP) using a hybrid sol-gel and annealed for 12 h at ≤200 °C. The grain sizes were in the range 10–20 nm but extensive shrinkage cracking was present. The crystallinities of the films annealed at ≤150 °C increased with increasing temperature gradually but only to a limited extent, although the crystallinity at 200 °C was significant. Recrystallisation resulted in decreased transparency, increased reflectivity, and a red shift to lower band gap. The methylene blue (MB) degradation was in the order 25 °C

TiO2 thin films of varying Co and Mo individual doping levels (0.00–1.00 mol% metal basis) were fabricated on soda-lime-silica glass substrates by spin coating, followed by annealing at 450 °C for 2 h. Mineralogical analyses showed that all of the films were comprised only of anatase and suggested that both Co and Mo formed interstitial solid solutions. For the Co-doped films, the variation in anatase XRD peak intensities indicated three discrete stages of structural and nanostructural development: recrystallization (≤0.05 mol% Co), lattice distortion (0.05–0.60 mol% Co), and precipitation (≥0.60 mol% Co). For the Mo-doped films, Mo consistently enhanced nucleation, recrystallization, and lattice distortion within the solubility limit, which was not reached at 1.00 mol% Mo. Chemical analyses showed that Ti4+/Ti3+, Co3+/Co2+, and Mo5+/Mo4+ (and possibly Mo6+) were present in the films. The formation of non-equilibrium valences was considered in terms of the effects of crystal field stabilization energy (CFSE), intervalence charge transfer (IVCT), and electronegativity. Nanostructural analyses of the Co-doped films showed that, with increasing doping level, the grain size increased at the lowest level, followed by a decrease owing to changes in the structure (lattice destabilization) and nanostructure (localized liquid formation). In contrast, the grain size of the Mo-doped films increased with increasing doping level due to the maintenance of solid solubility, defect formation (and associated enhanced nucleation and recrystallization), and grain growth. Defect formation and charge compensation resulted in lattice contraction, which was confirmed by laser Raman microspectroscopy and resultant destabilization. Optical analyses showed that all of the thin films were flat, smooth, and nanostructurally homogeneous. The band gap data suggested that the governing effect derived from the lattice distortion associated with the lattice incorporation of both dopants. Photocatalytic testing showed that the lowest level of doping for both dopants (0.01 mol%) yielded maximal photocatalytic activity and that the performance decreased with increasing doping levels. This was attributed to the effects of nucleation and recrystallization, semiconducting effect, dopant size effect, and minimal lattice distortion.

The present work reports structural/microstructural correlations with biological performance for three nanoceria morphologies, aiming to elucidate the major factors in their interactions with fibrosarcoma. These include the pH of the in vitro medium and the crystallinities, stoichiometries, surface areas and chemistries, and maximal oxygen vacancy concentrations ([VO••]Max). Although the [VO••]Max is dominant in the redox behavior, the role of the morphology was manifested in the order of effectiveness of the redox regulation, which was nanocubes (NC) < nanorods (NR) < nanooctahedra (NO). The proposed mechanism illustrates the role of VO•• in explaining antioxidant behavior at physiological pH 7.4 and prooxidant behavior in the tumor microenvironment pH 6.4. Cellular uptake at pH 7.4 was dominated by the morphology of the nanoparticle, demonstrating the order NO < NC < NR. Control of the [VO••]Max, morphology, and dependent structural and microstructural parameters can be used to optimize the uptake and r...

The present work reports data for the mineralogical, nanostructural, optical, and photocatalytic properties of Cr-doped, V-doped, and Cr/V-codoped TiO2 nanoparticles in terms of the effects of doping level and associated particle size on their photocatalytic performance. The photocatalytic performance of doped TiO2 is dependent not only on the particle size at low-doping levels but also on both the type and amount of dopant(s) at high-doping levels. These data illustrate the existence of two clear regimes in behaviour and enable the introduction of a new interpretation of the causes of these effects. At ultralow and low-doping levels, extrinsic effects (viz., particulate characteristics) determine the performance. At high-doping levels, intrinsic effects (viz., dopant-controlled chemical and electrical characteristics) determine the performance. In the intermediate range of medium-doping levels, the performance shows the mixed effects of these two factors. A schematic model comprehensively summarizing the role of doping in these extrinsic and intrinsic effects on the photocatalytic process is presented. Further, a phenomenological model that identifies the regions of dominance of these effects as a function of particle size and doping level on the photocatalytic performance is proposed. These generic models assist in both understanding the systematic effects of doping on photocatalysts and identifying approaches for modification.

The present work provides guidelines for the engineering of oxygen vacancy concentrations using morphology-maps based on the characteristics of nanoceria (CeO2−x) nanocubes, nanorods, and truncated nanooctahedra. These were characterised by XRD, TEM, BET, DLS, and XPS. The morphology maps reveal that the redox performance, particle size, and surface roughness (apparent porosity) can be optimised by engineering the oxygen vacancy concentrations, but the morphology is dominated by the reaction temperature. However, the oxygen vacancy concentration is controlled by the concentration of the NaOH precipitant/oxidant. These vacancies can be potentially located at the surface, subsurface, and bulk regions, but the subsurface vacancies provide the principal redox activity. The biological effects of nanoceria in terms of oxygen vacancies were analysed in normal and cancer cells. Nanoceria particles exhibit antioxidant and cytoprotective effects at physiological pH 7.4 but prooxidant and cytotoxic effects at tumour microenvironment pH 6.4. The relative redox performances and cytotoxicities are in the order nanocubes < nanorods < truncated nanooctahedra, which is a direct reflection of the relative oxygen vacancy concentrations. The redox performance of nanoceria has been contextualised by cellular uptake and its quantification in osteosarcoma cells.

The present work reports the rapid preparation of CeO2 nanorods by surfactant-free precipitation for the first time, which initiates a strategy for the quantitative elucidation of the importance of the exposed crystallographic planes and the oxygen vacancy concentrations of different morphologies of nanoceria. These relations are revealed through comparison of the relative surface areas of the exposed crystallographic planes. The precipitation temperature was critical in that nanooctahedra formed at the three lower temperatures and nanorods formed at the highest. The key feature to differentiate the photocatalytic performance was the morphology that the nanorods exhibit ∼200% superior performance compared to those of the nanooctahedra. The principal reason for this is the presence of exposed {110} planes in the nanorods, which are not present in nanoctahedra. This crystallographic dependence of the improved performance of the nanorods is attributed directly to the greater oxygen vacancy concentration for the calculated surface area of this morphology.

Monoclinic WO3 films with tunable (002) and (200) orientations parallel to fluorinedoped tin oxide substrates were electrodeposited from peroxotungstic acid (PTA) solutions and subjected to anneali ...

Bismuth-based metal oxide compounds are promising candidates as novel photocatalysts for environmental remediation. However, their low quantum efficiencies and rapid electron-hole recombination times have hindered their uptake for photocatalytic applications. The present work reports an investigation of the effects of variable Bi/Ti ratio during hydrothermal synthesis on the phase assemblage, nanostructure, surface chemistry, band gap, and photocatalytic performance. Increasing Ti concentration resulted in variations in characteristics and properties according to the sequential formation of the principal phases α-Bi2O3 (BO), Bi4Ti3O12 (BTO), and (Na0.5Bi0.5)TiO3 (NBT). Samples fabricated with precursors having a Bi/Ti ratio of 12/12 exhibited the highest methylene blue (MB) photodegradation rate of 92% under UV irradiation for 2 h. This excellent photocatalytic performance is attributed to the formation of an NBT/BTO heterojunction with advantageous band alignment.

Glass-ceramics (GCs) based on titanate pyrochlores have attracted recent attention as candidate waste forms for actinide immobilization. As zirconate pyrochlore has a superior radiation resistance, it is anticipated that Zr substitution of Ti in titanate pyrochlore GCs would increase their potential for waste form applications. The concept was primarily addressed via the preparation of Gd2Ti2-xZrxO7 (x = 0.1–0.3) GCs to determine the effects of sintering temperature, Zr substitution, and pyrochlore content (50–70 wt%) on the properties of the resultant GCs. XRD and SEM analyses were used to reveal the phase assemblages and microstructures while TEM and Raman spectroscopy were used to analyze the local structures. XRD results confirmed the formation of the targeted pyrochlore as the major phase, with Gd9.33(SiO4)6O2 oxyapatite present as a minor phase. SEM analyses revealed that up to 0.2 formula units of Ti could be substituted by Zr under the processing conditions. The pyrochlore crystallite sizes were largely controlled by the sintering temperature and cooling rate and showed little sensitivity to the glass contents. This work has demonstrated successful substitutions of Ti with Zr in Gd2Ti2O7 GCs as potential waste forms for actinide wastes owing to their superior radiation resistance.

This is the peer reviewed version of the following article: Zheng, X., Mofarah, S. S., Cazorla, C., Daiyan, R., Esmailpour, A. A., Scott, J., Yao, Y., Lim, S., Wong, V., Chen, E. Y., Arandiyan, H., Koshy, P., Sorrell, C. C., Decoupling the Impacts of Engineering Defects and Band Gap Alignment Mechanism on the Catalytic Performance of Holey 2D CeO2−x-Based Heterojunctions. Adv. Funct. Mater. 2021, 31, 2103171, which has been published in final form at https://doi.org/10.1002/adfm.202103171. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. Critical catalysis studies often lack elucidation of the mechanistic role of defect equilibria in solid solubility and charge compensation. This approach is applied to interpret the physicochemical properties and catalytic performance of a free-standing 2D–3D CeO2-x scaffold, which is comprised of holey 2D nanosheets, and its heterojunctions with MoO3-x and RuO2. The band gap alignment and structural defects are engineered using density functional theory (DFT) simulations and atomic characterization. Further, the heterojunctions are used in hydrogen evolution reaction (HER) and catalytic ozonation applications, and the impacts of the metal oxide heteroatoms are analyzed. A key outcome is that the principal regulator of the ozonation performance is not oxygen vacancies but the concentration of Ce3+ and Ce vacancies. Cation vacancy defects are measured to be as high as 8.1 at% for Ru-CeO2-x. The homogeneous distribution of chemisorbed, Mo-oxide, heterojunction nanoparticles on the CeO2-x holey nanosheets facilitates intervalence charge transfer, resulting in the dominant effect and resultant ˜50% decrease in overpotential for HER. The heterojunctions are tested for aqueous-catalytic ozonation of salicylic acid, revealing excellent catalytic performance from Mo doping despite the adverse impact of Ce vacancies. The present study highlights the use of defect engineering to leverage experimental and DFT results for band alignment.

The presence of kaolinite as mineral in coal may significantly influence coking properties of coal, therefore affects quality of coke that is produced from such coals. In this paper, the effect of kaolinite addition on pyrolysis behaviour of coal was examined by blending kaolinite with a medium rank, high vitrinite, low ash coal. Thermoplasticity of coal was characterised by using a Gieseler Plastometer. Char and tar samples were collected through pyrolysis at 450 °C in a Gray-King apparatus. The functional groups of the char samples were measured using FT-IR spectroscopy, while tar compositions were characterised using GC/MS. The results indicated that under the test conditions, addition of up to 5 wt% of kaolinite could increase the coal fluidity, attributed to the decrease in CH 3 /CH 2 ratio in the residual char. The proportion of C O/C C bonds affected the plastic range. Furthermore, the results showed that kaolinite addition suppresses the evolution of low molecular compounds in tar phase. This study provides useful information for optimising coal blending in cokemaking industry.

Microstructural features of coke particles are crucial for determining the performance of cokes in ironmaking blast furnaces. An analytical study was carried out to examine coke microstructure using image analysis. The microstructure parameters were correlated to the tensile strength of cokes. Coke properties were related to coal fluidity data based on Gieseler Plastometer measurements and other coal properties including quantitative mineralogy of coals using SIROQUANT analysis. Based on the microstructural data, a new modified microstructural parameter (S+) is proposed to characterize the heterogeneous nature of the physical structure of coke particles. The modified parameter was shown to have a good correlation with the tensile strength of coke as well as with the plastic range of the parent coals. Coal rank was shown to have a strong influence on the thermo-plasticity, with the results showing that there is an increase in both the maximum fluidity and plastic range of coals with increasing volatile matters of coal. The study highlighted the significance of coal mineral chemistry on coke particle characteristics from the observation that kaolinite-rich coals displayed a better correlation with the proposed modified parameter as well as the coke strength under the tested conditions. Stamp charging is also shown to have a positive impact on the microstructure as well as mechanical strength of cokes. This study has implications for the optimisation of the impact of coal chemistry and process conditions on coke quality.

The properties of mullite-glass and mullite-mullite interfaces have been investigated at 1800K by molecular dynamics (MD) simulation and high-resolution TEM. The simulation showed that mullite-glass interfaces typically have much lower interfacial energies than mullite-mullite interfaces, which results from the structural flexibility of the glass and associated accommodation of interfacial mismatch. The (110)-glass interface has the lowest energy of all interfaces studied, which is consistent with the observed dominance of this interface in experimental mullite-glass samples examined by TEM. The simulation shows that the interfacial energies of the (100)-glass and (010)-glass interfaces are higher than that those of the (001)-glass interface, so [100] and [010] would be expected to be the dominant growth directions. However, the growth of mullite in glass occurs predominantly in the [001] direction. This apparent discrepancy can be explained by the fact that growth in the [100] and [010] directions is limited by slow growth of (110) plane (i.e., [110] direction), which facilitates [001] growth, which are confirmed by the TEM data. This article is protected by copyright. All rights reserved.

Ce-doped TiO 2 thin films were prepared by sol-gel, spin coated on glass substrates, and annealed at 450 °C for 2 h. Solid solubility of Ce in anatase at the lowest doping level (≤0.25 mol% Ce) generated point defects that enhanced nucleation and recrystallization, resulting in relatively uniform grain sizes. In contrast, at ≥0.50 mol% Ce, overdoping, precipitation at grain boundaries, and liquid formation resulted in bimodal nanostructures with decreasing sizes of both the matrix grains and agglomerates owing to the progressive hindrance of Ti diffusion. The optimal photocatalytic performance at 0.25 mol% Ce was associated with a less densely packed array of fine matrix grains, while the performance at higher doping levels was dominated by liquid formation, greater packing densities, and blockage of active sites. The occurrence of Ce ↔ Ti intervalence charge transfer and associated oxygen vacancy formation are likely causes for the observed lowering of the band gap, reduction in the recombination rate, and enhancement of radiation absorption at longer wavelengths (red shift).

Highly-transparent V-doped TiO2 thin films were prepared by sol-gel processing, spin coated on fused silica glass substrates, and annealed in air at 450 °C for 2 h. All of the films were comprised of anatase as the sole crystalline phase. The XPS data suggested that V formed an interstitial solid solution with anatase. The formation of an unsaturated solid solution at the lowest doping level of 0.05 mol% resulted in the formation of lattice defect sites, which enhanced anatase recrystallisation, grain growth, and crystallinity. In contrast, the formation of supersaturated/oversaturated solid solutions at the higher doping levels of 0.10–1.00 mol% resulted in lattice deformation, partial amorphisation, precipitation, and liquid formation. The coexistence of multiple valence states, viz., Ti4+/3+, V4+/3+, and possibly V5+ in the doped TiO2 films was attributed to intervalence charge transfer. Dye degradation tests revealed that the 0.05 mol% V-doped films showed the best photocatalyic performance and this was attributed to the combined effects of greater anatase crystallinity and reduced band gap. In contrast, increasing V-doping levels resulted in gradual decreases in the photocatalytic performance, which are attributed principally to the decrease in areal density of the surface-active sites owing to liquid-phase densification. The greater degradation of MB solution relative to that of RhB solution is attributed principally to the cationic nature of MB, which allows greater adsorption on the photocatalyst surface in comparison to the anionic RhB.

Since there is increasing concern for the impact of air quality on human health, the present work surveys the materials and technologies for air purification using photocatalytic materials. The coverage includes (1) current photocatalytic materials for the decomposition of chemical contaminants and disinfection of pathogens present in air and (2) photocatalytic air purification systems that are used currently and under development. The present work focuses on five main themes. First, the mechanisms of photodegradation and photodisinfection are explained. Second, system designs for photocatalytic air purification are surveyed. Third, the photocatalytic materials used for air purification and their characteristics are considered, including both conventional and more recently developed photocatalysts. Fourth, the methods used to fabricate these materials are discussed. Fifth, the most significant coverage is devoted to materials design strategies aimed at improving the performance of photocatalysts for air purification. The review concludes with a brief consideration of promising future directions for materials research in photocatalysis.

The kinetics of the anorthite–Al system have been examined by exposing anorthite to pure Al at 850–1150 °C for 0.5–250 h. The interfaces were investigated by electron microscopy (SEM, EDS, EPMA, and TEM). The results showed that Si4+–Al3+ interdiffusion and associated oxygen vacancies plus Ca2+–Al3+ interdiffusion and associated calcium vacancies drove the anorthite → CA2 and the CA2 → A (alumina) transformations, respectively, at 850 and 950 °C. At 1050 and 1150 °C, increased solubilities of silicon and oxygen in the liquid Al resulted in significant formation of CA2, which, when in contact with anorthite, leads to formation of gehlenite. Si4+–Al3+ interdiffusion was identified as the controlling process of the anorthite–Al interactions and so it has been quantified in terms of the activation energy of Q = 112 kJ/mol and the diffusion coefficient pre-factor of D 0 = 4 × 10−8 m2/s.

Ceria (CeO2) nanorods have been prepared by simple short-term precipitation at room temperature for the first time using aqueous solutions based on Ce(NO3)3·6H2O and NaOH. TEM showed that (a) the two solutions alone yielded nanooctahedra of cross section ∼10 nm and (b) selective surface modification by isopropanol (IPA) played a significant role in the morphological development of approximately square nanorods of dimensions 4–5 nm width, 15–25 nm length, and [110] growth direction. DFT was used to assess surface energies and the interactions of the H2O and IPA molecules with the {111}, {110}, and {100} ceria surfaces. A growth mechanism on the basis of these adsorption energies and orientations is proposed and it depends on the favorable IPA adsorption energy. Its effect is twofold. First, it facilitates the formation of a {110} prism that alters the morphology from octahedral to spheroidal and then cuboidal. Second, the anisotropic electrostatic field in the electrical double layer, which is established by the oriented adsorption of the IPA molecule, is considered to facilitate the growth of the nanorod morphology. XPS data show that nanorods exhibit a greater concentration of Ce3+ (and associated oxygen vacancies) than do the nanooctahedra. The parameters determining the development of nanoparticle morphology are ranked in the order: packing density ≈ lattice spacing > IPA adsorption > H2O adsorption > surface energy. The present work suggests the applicability of crystallography considerations and DFT modeling to direct the crystal growth of specific morphologies.

Methanol decomposition is a promising method for hydrogen production. However, the performance of current catalysts for this process is not sufficient for commercial applications. In this work, methanol adsorption on the CeO

Oxygen vacancy concentrations are critical to the redox/photocatalytic performance of nanoceria, but their direct analysis is problematic under controlled atmospheres but essentially impossible under aqueous conditions. The present work provides three novel approaches to analyze these data from XPS data for the three main morphologies of nanoceria synthesized under aqueous conditions and tested using in vacuo analytical conditions. First, the total oxygen vacancy concentrations are decoupled quantitatively into surface-filled, subsurface-unfilled, and bulk values. Second, the relative surface areas are calculated for all exposed crystallographic planes. Third, XPS and redox performance data are deconvoluted according to the relative surface areas of these planes. Correlations based on two independent empirical results from volumetric surface XPS, combined with sequential deep XPS and independent EELS data, confirm that these approaches provide quantitative determinations of the different oxygen vacancy concentrations. Critically, the redox/photocatalytic performance depends not on the total oxygen vacancy concentration but on the concentration of the active sites on each plane in the form of subsurface-unfilled oxygen vacancies. This is verified by the pH-dependent performance, which can be increased significantly by exposing these vacancies to the surroundings. These approaches have significance to the design and engineering of semiconducting materials exposed to the environment.

Fe/Mo single doped and codoped TiO2 thin films were spin coated on polished fused silica substrates and annealed in air at 450 °C for 2 h. The XPS data for the anatase thin films were distinctive in showing that Fe-doping caused Ti4+ reduction, Mo-doping caused Ti4+ oxidation, and codoping did not alter the Ti valence. The XPS data also showed that the precursor valences of Fe3+ and Mo5+ were reduced upon annealing. Analysis of the potential roles of thermodynamics and intervalence charge transfer (IVCT) demonstrates that the latter drives the equilibria both in solution and during annealing. Photocatalytic performance testing indicated that Fe-doping was slightly deleterious, Mo doping had a consistent positive effect, and codoping exhibited a clear negative trend as a function of doping concentration. These results are interpreted in terms of the effect of IVCT on the matrix valence, dopant valences, and charge carrier trapping. Fe doping exhibited reduced performance because both matrix Ti(4−x)+ and dopant Fe(3−y)+ acted as electron traps. Mo doping exhibited enhanced performance because the matrix Ti(4+x)+ acted as a hole trap and the dopant Mo(5−x)+ and Mo(4−x)+ acted as electron traps, thereby promoting charge separation. Codoping exhibited a clearly detected negative trend on the performance because, while Ti4+ played no role, Fe(3−y)+, Mo(5−x)+, and Mo(4−x)+ all acted as traps for the majority charge carrier electrons.

The present work reports findings for the application of specialized aerospace aluminum rivets, manufactured from Al 7075 (Al-Zn-Mg-Cu) T6 alloy stem/mandrel, with an Al 5056 (Al-Mg) shank or sleeve, which were used for construction rectification of an outdoor louver façade on a high-rise building. These specialized rivets were used to replace failed conventional construction rivets, which consisted of sleeve and mandrel comprised of either all-steel, all-aluminum, or aluminum-steel. The building is in close vicinity to the ocean and exposed to extremely high wind loading, making the rivets susceptible to failure by corrosion and fatigue. The focus of the present work is to report the examination of the specialized replacement rivets following an in-service lifetime of 12 years. The examination revealed that the replacement rivets (mandrel and sleeve) remained intact and uncontaminated, essentially free of corrosion. It is likely that sunlight exposure and the composite nature of the rivets enhanced the performance through age hardening. Analysis of the rivets included visual inspection, optical microscopy, Vickers microhardness testing, and transmission electron microscopy. The aim of the analysis was to correlate microstructures with microhardnesses, using these data to evaluate the ultimate tensile strength (UTS), yield strength (YS), and the potential for further age hardening. The Vickers microhardnesses were observed to have increased by ~8% over the service lifetime of 12 years, which equates to increases in YS (34.8–46.8 MPa) and UTS (23.8–45.6 MPa). Although the results show that there is a large increase in the strength values when comparing the unused rivets to the 12-year-old rivets, this increase in hardness may not necessarily be due purely to natural aging kinetics such as exposure from the sun and outdoor temperature. However, there appears to be some insignificant alteration of the microstructure and mechanical properties as a result of this exposure.

The present work provides a concise examination of the historical global production levels of bauxite, primary aluminum, and secondary aluminum from 1850 to 2015. It also provides a contextual background to these data by summarizing the main etymological, technical, and commercial developments throughout most of this period. It further includes comprehensive data for the pricing of primary aluminum in both historical and 2015 dollars on the basis of economy cost. The syntheses of the data include the following: Global production levels of bauxite based on three data setsGlobal production levels of primary aluminum based on three data setsGlobal production levels of secondary aluminum based on three data setsComparative global production levels of secondary aluminum based on five data setsPrices of primary aluminum in historical US dollars and in US dollars indexed to 2015 values based on four data setsConversion rates for historical US dollars against 2015 valuesIn addition to the preceding global data, extensive pre-1900 data for French, Swiss, and US production levels and French and US prices of primary aluminum are compiled.

Altres ajuts: ICN2 is supported by the CERCA Programme/Generalitat de Catalunya. Holey 2D metal oxides have shown great promise as functional materials for energy storage and catalysts. Despite impressive performance, their processing is challenged by the requirement of templates plus capping agents or high temperatures; these materials also exhibit excessive thicknesses and low yields. The present work reports a metal-based coordination polymer (MCP) strategy to synthesize polycrystalline, holey, metal oxide (MO) nanosheets with thicknesses as low as two-unit cells. The process involves rapid exfoliation of bulk-layered, MCPs (Ce-, Ti-, Zr-based) into atomically thin MCPs at room temperature, followed by transformation into holey 2D MOs upon the removal of organic linkers in aqueous solution. Further, this work represents an extra step for decorating the holey nanosheets using precursors of transition metals to engineer their band alignments, establishing a route to optimize their photocatalysis. The work introduces a simple, high-yield, room-temperature, and template-free approach to synthesize ultrathin holey nanosheets with high-level functionalities.

Since the permeation of the inflammatory cytokines into hydrogel scaffolds has been shown to cause dysfunction of encapsulated cells, appropriate design strategies to circumvent this are essential. In the present work, it was hypothesized that highly crosslinked PVA-fucoidan and PVA-carrageenan hydrogels can control permeation of the trefoil-shaped inflammatory cytokine IL-1β while allowing the permeation of the globular protein albumin. PVA, fucoidan, and carrageenans were functionalized with methacrylate groups and the functionalized polymers were co-crosslinked by UV photopolymerization. The resultant hydrogels were characterized physicochemically and the release of fucoidan and carrageenans was quantified by developing a colorimetric assay, which was validated by XPS analysis. The permeability characteristics of the hydrogels were evaluated using bovine serum albumin (BSA), IgG, and IL-1β. The results demonstrated an increase in hydrogel swelling through the incorporation of the polysaccharides with minimal overall mass loss. The release studies showed hydrogel stability, where the formulations exhibited ~43% retention of fucoidan and ~60-80% retention of carrageenans consistently up to 7 days. The permeation data revealed very low permeation of IgG and IL-1β through the hydrogels, with1% permeation after 24 h, while allowing6% permeation of BSA. These data indicate that such hydrogels can be used as the basis for cytokine-protective implantable devices for clinical applications.

Fly ash is an aluminosilicate and the major by‐product from coal combustion in power stations, its increasing volumes are major economic and environmental concerns, particularly since it is one of the largest mineral resources based on current estimates. Mullite (3Al2O3&middot, 2SiO2) is the only stable phase in the Al2O3‐SiO2 system and is used in numerous applications owing to its high‐temperature chemical and mechanical stabilities. Hence, fly ash offers a potential economical resource for mullite fabrication, which is confirmed by a review of the current literature. This review details the methodologies to utilise fly ash with different additives to fabricate what are described as porous interconnected mullite skeletons or dense mullite bodies of approximately stoichiometric compositions. However, studies of pure fly ash examined only high‐Al2O3 forms and none of these works reported long‐term, high‐temperature, firing shrinkage data for these mullite bodies. In the present work, high‐SiO2 fly ashes were used to fabricate percolated mullite, which is demonstrated by the absence of firing shrinkage upon long‐term high‐temperature soaking. The major glass component of the fly ash provides viscosities suitably high for shape retention but low enough for ionic diffusion and the minor mullite component provides the nucleating agent to grow mullite needles into a direct‐bonded, single‐crystal, continuous, needle network that prevents high‐temperature deformation and isolates the residual glass in the triple points. These attributes confer outstanding long‐term dimensional stability at temperatures exceeding 1500&deg, C, which is unprecedented for mullite‐based compositions.

Anatase thin films were prepared by sol-gel, spin coated on glass, and annealed (450 °C/2 h). The effects of cobalt and vanadium doping (0.05–1.00 mol%) on the mineralogical (GAXRD, Raman), nanostructural (AFM), optical (UV-Vis), and chemical (XPS) properties were considered. A new perspective of the role of ionic size effects on substitutional (Co2+) and interstitial (V3+) solid solubility in the elongated TiO6 octahedron and the consequent roles of lattice deformation and charge compensation is presented. The role of intervalence charge transfer (transient, permanent) and the effects of electronegativity and electron affinity on the presence and absence of ions of different valence states also are considered, explaining the detection of nonequilibrium V4+ and the nondetection of Ti3+. The data are interpreted according to a model for nanostructural evolution during annealing, which allows interpretation of the film thickness and roughness, grain and crystallite sizes, and band gap as a function of dopant concentration. The detection of high levels of contamination from the glass substrates, which decreased during aqueous methylene blue (MB) testing (≤24 h), indicates the likelihood of mass transport by grain boundary diffusion of these ions (Na+, Mg2+, Ca2+, Si4+). This leaching impacted on the loss of dopant ions precipitated on the grain surfaces following the achievement of saturation solubility, as suggested by the calculation of the relevant speciation and Pourbaix diagrams. The photocatalytic performance by MB testing revealed that Co (precipitated) had a deleterious effect at all levels while V (dissolved) showed slight improvements over undoped TiO2 at most levels.

The present work reports the SEM, EPMA and TEM examination of reactions at the interface of Al7075 alloy and a 50/50 wt% mixture of BaAl2Si2O8 + CaAl2Si2O8 feldspars at 850 °C, 1150 °C and 1250 °C. Sintering of the feldspar mixture at 1450 °C caused dissolution of ~1.0 wt% Ca in BaAl2Si2O8 and 0.5 wt% Ba in CaAl2Si2O8. The interaction of the Al alloy with the sintered feldspars shifted the alloy composition to the Al–Si–αBaAl2Si2 and Al–Si–βaAl2Si2 compatibility triangles. The feldspars underwent a series of phase transformations, leading ultimately to the formation of Al2O3.

Highly-transparent TiO 2 thin films with varying W-dopant levels (0.010–0.100 mol%) were deposited on soda-lime-silica glass substrates by spin coating, followed by annealing in air at 450 °C for 2 h. Characterization was by GAXRD, AFM, SIMS, XPS, UV–vis, and MB degradation. The films were comprised of single-crystal anatase grains. Increasing doping levels increased the crystallite sizes, grain sizes, and film thicknesses; they also changed the grain morphology from anhedral to euhedral. W 6+ ions formed a substitutional solid solution in anatase and probably exhibited charge compensation by Ti vacancy formation, which led to lattice contraction. Contamination from the glass substrates was homogeneously distributed on the grain boundaries. Doping decreased the optical indirect band gap. However, at the highest doping level, it is not certain if this was an artificial effect of precipitation from overdoping or a true effect of lattice stress. The 0.010 mol% W sample showed the best performance probably owing to its formation of a homogeneous solid solution within the range of semiconducting properties, which could have narrowed the band gap or introduced mid-gap states. The 0.100 mol% W sample may have been overdoped and caused WO 3 precipitation. If so, the presence of the TiO 2 –WO 3 couple may have enhanced charge separation and hence photocatalytic performance.

Proton activities of suspensions of Ti particles with added cationic polyelectrolyte as a function of acid additions have been investigated and compared in terms of the electrophoretic mobility and deposition yield. The proton activity in ethanol medium decreased with the addition of PEI polyelectrolyte and reduced further in the presence of Ti particles. The decrease in proton activity in the suspension indicates that protonation occurred on both the PEI molecules and Ti particles. It is proposed that the protonation of the amine groups of PEI and hydroxyl sites of Ti particle led to the formation of hydrogen bonding between the Ti particle and PEI molecules. Increase in the PEI and Ti with increasing acid addition translated to higher electrophoretic mobilities and deposition yield at low ranges of acetic acid addition (

The present work on the mechanical properties of ≤10 wt% fly ash additions in 2.5 wt% increments to recycled high-density polyethylene (RHDPE) synthesizes experimental data from three similar published reports. The present work shows, as a function of increasing fly ash addition level, maxima at the initial fly ash addition level of 2.5 wt% for the tensile elastic modulus (+25%) and tensile strength (+10%); a slight general increase in the yield stress (+6%); and significant general decreases in the yield strain (−61%), elongation at break (−92%), and Charpy impact strength (−55%). Combining these data with data for higher-level additions of fly ash (≤40 wt%/23 vol%) and cenospheres (≤39 vol%) to HDPE or RHDPE provides the basis for design parameters and a generalized model for the interpretation of failure of composites of hard brittle spherical dispersant additions in ductile polymeric matrices. The relevant load-extension plots are characterized by three behavioral regions: ductile deformation (dispersion strengthening and stress concentration), crazing (debonding and cavitation), and brittle failure (fibril failure). The locations of these regions and their transitions are a function of five dependent variables: dispersant volume, dispersant particle size, intrinsic flaw size (viz., dispersant size), generated flaw size (viz., void size), and interfacial bond strength and associated load transfer. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

TiO x C y powders with tunable composition and high specific surface areas have been synthesized by impregnation of porous carbon black with titanium isopropoxide and firing in argon at 1400 °C. The compositional ratio of the individual ions can be controlled over a broad compositional range by tuning the stoichiometric ratio of the initial reactants. The resultant powders show no detectable oxide or carbonaceous impurity phases. The powders retain artefacts of the porosity of the templating carbon and yield specific surface areas as high as 108 m 2 g −1 , which makes them useful in catalytic/electrocatalytic applications.

Undoped and Fe-doped CeO2 thin films were fabricated by spin coating on F-doped tin oxide glass substrates followed by annealing at 500 °C for 15 h. The concentration of the dopant was varied from 2 to 10 % iron by weight (metal basic). Glancing angle X-ray diffraction and laser Raman microspectroscopy indicated that the films consisted only of CeO2 without any impurity phases of FexOy. The thickness of the films was determined by dual-beam focused ion beam milling to be ~150 nm for undoped film, while Fe-doped CeO2 films have thickness of ~200 nm for all dopant samples. The transmission spectra from UV–visible spectrophotometry showed a redshift of the absorption edge of the doped films, and the optical indirect band gap of the films decreased from 3.48 to 3.20 eV with increasing dopant concentration. Furthermore, the results have been proposed in the diagram of electron–hole trapping.

This work investigates the interfacial interactions of Al7075 alloy with BaAl2Si2O8 at high temperatures [1423 K and 1523 K (1150 °C and 1250 °C)]. X-ray diffraction, electron probe microanalysis, and scanning electron microscopy coupled with energy dispersive spectroscopy were used to identify the mineralogical and microstructural changes at the interfaces. The vaporization, migration, and subsequent oxidation of alloying constituents (Mg and Zn) in contact with BaAl2Si2O8 caused intense interfacial phase transformations, forming spinel solid solution, magnesia solid solution, celsian-based solid solution, and barium magnesium silicate solid solution. The driving force for these phase transformations at the reaction front is the interdiffusion processes between Al (or Mg/Zn)-Si and Mg (or Zn)-Ba that occurs owing to the relative elemental gradients. The rate-limiting step of corrosion kinetics was identified to be Ba substitution in the MgO structure. The corrosion mechanism (extensive phase transformation of Ba-celsian by interdiffusion processes) at high temperatures was found to be different from that observed at lower temperatures [1123 K (850 °C)].

The present work reports an investigation of the interactions of Al 7075 alloy and anorthite at 850°C (150 h) and 1150°C (24 h). Transmission electron microscopy, electron probe microanalysis, X-ray diffraction, and scanning electron microscopy coupled with energy-dispersive spectroscopy were used to identify the mineralogical and microstructural changes at the metal–ceramic interface. At 850°C, the phase formation mechanisms were (a) Si4+–Al3+ interdiffusion between the Al alloy and anorthite to form calcium dialuminate (CA2) and Ca2+–Mg2+ interdiffusion between the Al alloy and calcium dialuminate to form spinel. At 1150°C, spinel + Al2O3 and calcium hexaluminate (CA6) + CA2 were the major and minor phase mixtures, respectively in the corroded area. A thin layer of calcium monoaluminate (CA), gehlenite, and Si was present in the immediate vicinity of anorthite. The early stages of corrosion at 1150°C and 850°C were identical. However, due to thickening of the corroded region (viz., spinel formation) and enhanced evaporation of Mg at the higher temperature, the interdiffusion path evolves from Si4+–Al3+ + Ca2+–Mg2+ to Si4+–Al3+ + Ca2+–Al3+, thus establishing the following phase evolution path at the interface: Anorthite→Gehlenite→CA→CA2→CA6→Al2O3

V-doped, Mo-doped, and codoped anatase powders have been fabricated by hydrothermal synthesis at 150 °C for 20 h, followed by calcining at 500 °C for 4 h in air. The raw materials were titanium tetra-isopropoxide, VCl3, and MoCl5 and the doping levels were in the relatively low range of 0.02–0.08 mol% (metal basis). The samples were characterized by XRD, SEM, FESEM, BET, UV–Vis spectrophotometry, XPS, and MB degradation by UV–Vis and simulated-solar light spectrophotometry. All of the powders consisted of anatase only and the crystallinities decreased for all dopant levels. For all samples as a function of dopant level, the grain sizes were similar and in the range ∼ 1– 5 μ m , with some dense agglomerates of size up to ∼ 20 μ m , although individual grains consisted of highly agglomerated nanoscale particles. For the doped samples, the crystallite sizes generally decreased, the surface areas were consistent, and the band gaps decreased for V doping but increased for Mo doping. The codoped samples appeared to be dominated by the V doping as they exhibited similar trends. These trends were interpreted largely in terms of the effects of irregular, clustered, or homogeneous dopant distribution on the nucleation and grain growth. The XPS data revealed the presence of V 5 + , Mo 4 + , Mo 5 + , Ti 3 + , and Ti 4 + . The presence of these dopants and their variable valence states was interpreted in terms of intervalence charge transfer (IVCT) and multivalence charge transfer (MVCT) and the associated introduction of midgap states, which represent key parameters in the semiconducting behavior of these doped materials. The irregular trends in photocatalytic performance as a function of dopant level and an increasing trend for the codoped samples revealed the competition between the positive effects of decreasing crystallite size and increasing role of midgap states versus the negative effects of decreasing crystallinity for the doped samples and the dominance of the former two factors for the codoped samples.

TiO2 coatings were fabricated by anodizing unpolished and polished Ti6Al4V substrates in 1–3 M H2SO4 for 10 and 20 min at 120 V. Anatase was the principal polymorph and oxygen dissolution in the Ti6Al4V substrates caused αTi lattice contraction. Dielectric breakdown and associated heating of the insulating TiO2 promoted trace rutile formation. The surface preparation of the Ti6Al4V substrates was the principal factor that determined not only the grain and pore sizes but also the morphology and topography of the coating. Consequently, the presence of the amorphous TiO2 passivating layer (unpolished) resulted in thicker and more irregular coatings than when anodization was done on the bare metal surface (polished). Large-scale delamination steps were observed for the coatings on the unpolished substrates while localized delaminations occurred for the coatings on polished substrates; the amounts of both increased with increasing anodization time. 3D laser scanning confocal microscopy allowed distinction between the fine-scale morphology and the coarse-scale topography. These data showed that increasing time and acid concentration resulted in similar trends of increasing roughness (morphology) and unevenness (topography). The present work focusses on the effect of initial substrate surface characteristics and its modification to improve the quality of the coatings formed by anodization of titanium biomedical implants.

Photocatalytic materials are pivotal for the implementation of disruptive clean energy applications such as conversion of H$_{2}$O and CO$_{2}$ into fuels and chemicals driven by solar energy. However, efficient and cost-effective materials able to catalyze the chemical reactions of interest when exposed to visible light are scarce due to the stringent electronic conditions that they must satisfy. Chemical and nanostructuring approaches are capable of improving the catalytic performance of known photoactive compounds however the complexity of the synthesized nanomaterials and sophistication of the employed methods make systematic design of photocatalysts difficult. Here, we show by means of first-principles simulation methods that application of biaxial stress, $\eta$, on semiconductor oxide thin films can modify their optoelectronic and catalytic properties in a significant and predictable manner. In particular, we show that upon moderate tensile strains CeO$_{2}$ and TiO$_{2}$ thin films become suitable materials for photocatalytic conversion of H$_{2}$O into H$_{2}$ and CO$_{2}$ into CH$_{4}$ under sunlight. The band gap shifts induced by $\eta$ are reproduced qualitatively by a simple analytical model that depends only on structural and dielectric susceptibility changes. Thus, epitaxial strain represents a promising route for methodical screening and rational design of photocatalytic materials.

Innovative approaches to the control of immune response to tissue engineering scaffolds is of high priority. IL-10, an anti-inflammatory cytokine, has traditionally been conjugated to synthetic polymers for local immunomodulation. Marine-sulfated polysaccharides have been reported to possess anti-inflammatory properties. In the present work, it was hypothesized that photopolymerizable fucoidan and carrageenan play similar roles as the IL-10. The polysaccharides were functionalized with methacrylate groups. Their immunomodulatory properties were evaluated and compared relative to IL-10. The polysaccharides were characterized by NMR spectroscopy, revealing 12-13 % functionalization. The data revealed that fucoidan had the same activity as the IL-10 in decreasing LPS- and IFN-γ-stimulated CD86 expression. In addition, fucoidan had a protective role against LPS- and IFN-γ-induced cell growth inhibition. All polysaccharides demonstrated ∼90 % superoxide radical scavenging and they considerably decreased LPS-stimulated nitric oxide production. These results suggest that photopolymerizable fucoidan can be an alternative to IL-10 in the design of immunomodulatory biomaterials.

Conductive metal oxides represent a new category of functional material with vital importance for many modern applications. The present work introduces a new conductive metal oxide V

Background In this study, a historical case series is reported of reaction bonded silicon nitride (Si3N4) implants for anterior lumbar interbody fusion (ALIF) for a patient population of 30 and surgery levels L3/4, L4/5, and/or L5/S1. Before the study, the only work on Si3N4 as a biomedical material was associated preliminary work, which involved animal trials using a rabbit model. The objective was to undertake the first use of Si3N4 as a biomedical material for humans, as an implant for ALIF. Methods The Si3N4 implants were prepared by die-pressing silicon powder and reaction bonding in 95 N2/5 H2 at ∼1400°C for ∼50 hours. The surgeries involved a retroperitoneal approach for L3/4 and L4/5 levels and a transperitoneal approach for L5/S1 level. The patient follow-up involved assessment of radiologic fusion up to 30 years and clinical outcomes to 10 years. Results The reaction bonded Si3N4 implants were found to be biologically safe and to show high fusion rates with minimal subsidence, no abnormal reaction, and no other complications. The primary outcome measure, visual analog scale back pain, improved from a preoperative mean of 8.4 (range, 6–10) to a mean of 3.7 (range, 0–9) at 5 years and a mean of 4.9 (range, 0–9) at 10 years. The Oswestry Disability Index improved from a preoperative mean of 48 (range, 26–84) to a mean of 35 (range, 4–76) at 10 years. Conclusions This study confirms that Si3N4 is biologically safe in the long-term, with capacity for excellent radiologic osseointegration.

International audience; The Pechini method was more effective in fabricating Ce/Cr codoped TiO2 nanoparticles of superior photocatalytic properties in comparison with the sol-gel method. The improved efficiency was attributed to: a) formation of mixed-phase anatase + rutile with greater homogeneity of dopant incorporation, b) development of open agglomerated morphologies with significantly higher surface areas, and c) favourable valence changes (increased Ti 3+ concentrations) owing to electron exchange in inter valence and/or multi valence charge transfer reactions. Chen, Wen-Fan, et al. "Enhancement of Ce/Cr Codopant Solubility and Abstract Ce/Cr codoped TiO2 nanoparticles were synthesized using sol-gel and Pechini methods with heat treatment at 400°C for 4 h. A conventional sol-gel process produced well crystallized anatase while Pechini synthesis yielded less ordered mixed-phase anatase + rutile; this suggests that the latter method enhances Ce solubility, increases chemical homogeneity, but destabilizes the TiO2 lattice. Greater structural disruption from the decomposition of the Pechini precursor formed more open agglomerated morphologies while the lower levels of structural disruption from pyrolysis of the dried sol-gel precursor resulted in denser agglomerates of lower surface areas. Codoping and associated destabilization of the lattice reduced the binding energies in both powders. Cr 4+ formation in sol-gel powders and Cr 6+ formation in Pechini powders suggest that these valence changes derive from synergistic electron exchange from intervalence and/or multivalence charge transfer. Since Ce is too large to allow either substitutional or interstitial solid solubility, the concept of integrated solubility is introduced, in which the Ti site and an adjacent interstice are occupied by the large Ce ion. The photocatalytic performance data show that codoping was detrimental owing to the effects of reduced crystallinity from lattice destabilization and surface area. Two regimes of mechanistic behavior are seen, which are attributed to the unsaturated solid solutions at lower codopant levels and supersaturated solid solutions at higher levels. The present work demonstrates that the Pechini method offers a processing technique that is superior to sol-gel because the former facilitates solid solubility and consequent chemical homogeneity.