High Surface Area Metal Oxides Research Articles

High Surface Area Metal Oxide Enhanced Self-Powered Microfluidic Device for Real-Time Pathological Detection

Biomarkers based sensing in the realm of disease prevention, its diagnosis, and drug development has shown its unique importance in health care. In particular, the platelet level in blood is strongly linked with the development of several kind of severe diseases like coronavirus disease 2019, diabetes, and microbial infections as well as individuals undergoing cancer diagnosis. Currently, commercial methods employed for platelet level determination in whole-blood are based on Coulter principle, flow cytometry, and image analysis. However, these technologies are intricate, time consuming, expensive, and require a trained operator as well as lack of portability. Considering these issues, we have developed a self-powered portable device for real-time platelet level monitoring, aimed towards point-of-care applications. The fabricated self-powered-microfluidic triboelectric nanogenerator (SPM-TENG) utilized test sample flow-resistance for sensing of platelet level and triboelectric voltage output as sensing signal. For the fine tuning of fabricated SPM-TENG, we compared the triboelectric voltage output from gold electrode measurement setup and terminal electrode measurement setup. In view of further improvement in stability, voltage output and to minimize the noise in sensing signals, the geometrical optimization of microfluidic channel was performed. In conclusion we have optimized the device as a terminal electrode measurement setup with copper tubes on terminals of microfluidic channel and copper oxide nanowires grown on the interior of copper tubes. These copper oxide nanowires provide a high surface area for solid-liquid contact separation and is responsible for enhanced sensing signal. The fabricated SPM-TENG has shown its great potential in platelet level sensing with plasma-based samples as well as whole-blood samples. The proposed device demonstrated its practicality towards real-time rapid sensing of platelet level and portability.

Synthesis of high-surface-area mesoporous SnO2 nanomaterials using carbon template

Metal oxide porous nanomaterials are of great interest across scientific fields due to their intriguing properties, allowing their usage from lab-scale research to industrial applications. However, the production of high surface area metal oxide nanomaterials still poses significant challenges. This study introduces a novel method for synthesizing highly porous tin oxide (SnO2) nanostructures using carbon as the template material. The synthesis process includes the formation of a precursor composite containing resorcinol-formaldehyde gel and a tin oxide precursor, which is first carbonized to convert the resorcinol-formaldehyde into a porous three-dimensional carbon framework. This framework acts as a scaffold for the nucleation of SnO2 nanoparticles. Subsequent oxidation selectively removes the carbon template, yielding highly porous SnO2 nanomaterials. Electron microscopy analysis shows that the nanomaterials feature a particle size with average diameter of ∼30 nm, whereas Gas adsorption-desorption characterization indicates pronounced mesoporosity, with a pore size of 3 nm and a specific surface area of 476 m2/g. The enhanced surface area surpasses the previously reported studies on porous SnO2. This is significant considering the easy production process of the nanomaterials, which signifies its potential for large-scale production. Furthermore, this approach offers versatility, as different materials can replace the carbon component, allowing for tailored nanostructure design and enhanced properties. The resulting materials can offer exciting possibilities in the field of materials science and nanotechnology.

Synthesis of High Surface Area-Group 13-Metal Oxides via Atomic Layer Deposition on Mesoporous Silica.

The atomic layer deposition of gallium and indium oxide was investigated on mesoporous silica powder and compared to the related aluminum oxide process. The respective oxide (GaOx, InOx) was deposited using sequential dosing of trimethylgallium or trimethylindium and water at 150 °C. In-situ thermogravimetry provided direct insight into the growth rates and deposition behavior. The highly amorphous and well-dispersed nature of the oxides was shown by XRD and STEM EDX-mappings. N2 sorption analysis revealed that both ALD processes resulted in high specific surface areas while maintaining the pore structure. The stoichiometry of GaOx and InOx was suggested by thermogravimetry and confirmed by XPS. FTIR and solid-state NMR were conducted to investigate the ligand deposition behavior and thermogravimetric data helped estimate the layer thicknesses. Finally, this study provides a deeper understanding of ALD on powder substrates and enables the precise synthesis of high surface area metal oxides for catalytic applications.

Ni-Fe-layered double hydroxide/N-doped graphene oxide nanocomposite for the highly efficient removal of Pb(II) and Cd(II) ions from water

Heavy metal removal from industrial wastewater has remained a tremendous challenge as the water pollution caused by them is posing a serious ecological threat. Several nanostructured materials have been developed for effective scavenging of water-borne metal ions, including high surface area metal oxides, mesoporous silica and carbon based materials. The oxide mediated interaction between the metal ions and the adsorbent leads to efficient loading of these toxic metal ions. Therefore, in order to design a highly efficient adsorbent for trapping toxic lead and cadmium ions from wastewater, a nanocomposite of Ni-Fe layered double hydroxide with N-doped graphene oxide have been synthesized via co-precipitation technique at ambient conditions and its metal adsorption characteristics have been further investigated under varying conditions such as pH, concentration, adsorbent loading and the time of contact. This novel nanocomposite has been found to exhibit Langmuir type adsorption of the metal ions indicating chemical nature of their adsorption on the surface of the nanocomposite and significantly higher adsorption efficiency as compared to the individual constituents. The adsorption process was found to follow a pseudo second-order rate equation with a rate constant of 0.025 g mg−1min−1. The nanocomposite was found to have a very high loading capacity of ∼1000 mg/g for both lead and cadmium ions respectively. It also works well over a wide pH range (5–11) and the adsorbent can be easily regenerated after use. Thus, this material holds strong potential for applications in the treatment of heavy metal intoxicated industrial wastewater.

Catalytic pyrolysis of lignin with red mud derived hierarchical porous catalyst for alkyl-phenols and hydrocarbons production

Red mud (RM) was activated by a feasible digestion-precipitation method followed by calcination at 600 °C (denoted as ACRM), which was used as a novel catalyst during the thermal degradation of the lignin. The prepared catalyst was then applied to the lignin derived from agricultural waste using a vertical fixed-bed microreactor between 350–650 °C. The texture characteristics of the activated RM were characterized by XRF, FTIR, XRD, TEM, SEM-EDS, NH3-TPD, and the N2 isothermal absorption method. The analysis results indicated that the ACRM catalyst possessed a high specific surface area, hierarchical porosity, acidity and active metal oxides (Fe2O3, Al2O3, and TiO2). Maximum bio-oil yield (25 wt.%) was observed at 550 °C, however, the bio-oil yield exhibited an overall declined trend in comparison to the non-catalytic pyrolysis at the corresponding pyrolysis temperatures. The relative contents of alkyl-phenols and the hydrocarbons significantly increased using the ACRM catalyst at 550 °C, which was attributed to the strengthening of dehydroxylation, demethylation, demethoxylation, and alkylation reactions. The study demonstrated the ACRM could be used as a promising catalyst for upgrading the pyrolysis vapours of lignin with considerable economic and ecological benefits.

(Invited) Metal Oxide Nanocoating As Electrocatalyst Support, and More

With a standard electrochemical oxidation potential at 0.207 V, carbon is prone to being oxidized in PEM fuel cells. This has been observed over the years and addressed by using system controls in fuel cell vehicles. While adding a control system can resolve the problem, it also adds more weight and cost to fuel cell vehicles. Electrochemical corrosion of carbon can be a serious problem in many other kinetically accelerated processes, for example, rechargeable batteries and pseudocapacitors. Certain metal oxides have been studied as possible replacements for carbon. In this talk, I will present our studies on preparing high surface area metal oxides in the form of nanocoatings. In particular, a newly developed technique to make titania and niobia nanocoatings on different carbons, including carbon black and carbon nanotubes, will be presented. To make the oxides electrically conductive, carbon activation and elemental doping were shown to be effective. Furthermore, electronic interactions of metal catalyst nanoparticles and metal oxides will be discussed in terms of promotion of electrocatalytic activity.

Multimolecular assemblies on high surface area metal oxides and their role in interfacial energy and electron transfer.

High surface area metal oxides offer a unique substrate for the assembly of multiple molecular components at an interface. The choice of molecules, metal oxide, and the nature of the assembly method can have a profound influence on the mechanism, rate, and efficiency of photoinduced energy and electron transfer events at the interface. Owing to their diversity and high level of control, these interfacial assemblies are of interest for numerous applications including solar energy conversion, photoelectrosynthesis, photo-writable memory, and more. Although these assemblies are generated with very different goals in mind, they rely on similar surface binding motifs and molecular structure-property relationships. Therefore, the goal of this review is to summarize the various strategies (i.e. co-deposition, axial coordination, metal ion linkages, electrostatics, host-guest interactions, etc.) for assembling chromophores, hosts, electron donors/acceptors, and insulating co-adsorbent molecules on mesoporous metal oxide substrates. The assembly, synthesis, and characterization, as well as subsequent photoinduced events (i.e. cross-surface energy/electron transfer, interchromophore energy transfer, electron injection, and others) are discussed for the various assembly strategies.

Microwave exfoliated graphene oxide/TiO2 nanowire hybrid for high performance lithium ion battery

Lithium ion battery (LIB) is a key solution to the demand of ever-improving, high energy density, clean-alternative energy systems. In LIB, graphite is the most commonly used anode material; however, lithium-ion intercalation in graphite is limited, hindering the battery charge rate and capacity. To date, one of the approaches in LIB performance improvement is by using porous carbon (PC) to replace graphite as anode material. PC's pore structure facilitates ion transport and has been proven to be an excellent anode material candidate in high power density LIBs. In addition, to overcome the limited lithium-ion intercalation obstacle, nanostructured anode assembly has been extensively studied to increase the lithium-ion diffusion rate. Among these approaches, high specific surface area metal oxide nanowires connecting nanostructured carbon materials accumulation have shown promising results for enhanced lithium-ion intercalation. Herein, we demonstrate a hydrothermal approach of growing TiO2 nanowires (TON) on microwave exfoliated graphene oxide (MEGO) to further improve LIB performance over PC. This MEGO-TON hybrid not only uses the high surface area of MEGO but also increases the specific surface area for electrode–electrolyte interaction. Therefore, this new nanowire/MEGO hybrid anode material enhances both the specific capacity and charge–discharge rate. Scanning electron microscopy and X-ray diffraction were used for materials characterization. Battery analyzer was used for measuring the electrical performance of the battery. The testing results have shown that MEGO-TON hybrid provides up to 80% increment of specific capacity compared to PC anode.

Thermal Stability Limits of Imidazolium Ionic Liquids Immobilized on Metal-Oxides.

Thermal stability limits of 33 imidazolium ionic liquids (ILs) immobilized on three of the most commonly used high surface area metal-oxides, SiO2, γ-Al2O3, and MgO, were investigated. ILs were chosen from a family of 13 cations and 18 anions. Results show that the acidity of C2H of an imidazolium ring is one of the key factors controlling the thermal stability. An increase in C2H bonding strength of ILs leads to an increase in their stability limits accompanied by a decrease in interionic energy. Systematic changes in IL structure, such as changes in electronic structure and size of anion/cation, methylation on C2 site, and substitution of alkyl groups on the imidazolium ring with functional groups have significant effects on thermal stability limits. Furthermore, thermal stability limits of ILs are influenced strongly by acidic character of the metal-oxide surface. Generally, as the point of zero charge (PZC) of the metal-oxide increases from SiO2 to MgO, the interactions of IL and metal-oxide dominate over interionic interactions, and metal-oxide becomes the significant factor controlling the stability limits. However, thermal stability limits of some ILs show the opposite trend, as the chemical activities of the cation functional group or the electron donating properties of the anion alter IL/metal-oxide interactions. Results presented here can help in choosing the most suitable ILs for materials involving ILs supported on metal-oxides, such as for supported ionic liquid membranes (SILM) in separation applications or for solid catalyst with ionic liquid layer (SCILL) and supported ionic liquid phase (SILP) catalysts in catalysis.

Synthesis of metal oxide nanoparticles via a robust "solvent-deficient" method.

We report an efficient, general methodology for producing high-surface area metal oxide nanomaterials for a vast range of metal oxides, including at least one metal oxide nanomaterial from nearly every transition metal and semi-metal group in the periodic table (groups 3-4 and 6-15) as well as several from the lanthanide group (see ). The method requires only 2-3 simple steps; a hydrated metal salt (usually a nitrate or chloride salt) is ground with bicarbonate (usually NH4HCO3) for 10-30 minutes to form a precursor that is then either untreated or rinsed before being calcined at relatively low temperatures (220-550 °C) for 1-3 hours. The method is thus similar to surfactant-free aqueous methods such as co-precipitation but is unique in that no solvents are added. The resulting "solvent-deficient" environment has interesting and unique consequences, including increased crystallinity of the products over other aqueous methods and a mesoporous nature in the inevitable agglomerates. The products are chemically pure and phase pure with crystallites generally 3-30 nm in average size that aggregate into high surface area, mesoporous agglomerates 50-300 nm in size that would be useful for catalyst and gas sensing applications. The versatility of products and efficiency of the method lend its unique potential for improving the industrial viability of a broad family of useful metal oxide nanomaterials. In this paper, we outline the methodology of the solvent-deficient method using our understanding of its mechanism, and we describe the range and quality of nanomaterials it has produced thus far.

Modification of Pd for formic acid decomposition by support grafted functional groups

AbstractFormic acid is proposed as a storage material to supply hydrogen gas for small portable fuel cell devices. However catalysts for its decomposition must be highly active and selective to provide a high quantity of hydrogen and carbon dioxide at ambient conditions but prevent any CO formation that can poison the catalysts. In this paper we report the functionalization of high surface area metal oxides with amine groups, which are then utilized as catalyst support to host Pd nanoparticles. It is demonstrated that the electronic and geometric properties of Pd nanoparticles can be substantially modified by these functionalized supports, resulting in improved activity and selectivity performance for the formic acid dehydrogenation.

Development of Continuous and Ultrathin Pt Electrocatalysts Using Plasma-Assisted ALD

High cost of Pt prevents wide-spread application of fuel cell vehicles. Fine nanoparticles (3-5nm in diameter) are traditionally used in order to increase electrochemically active surface area. A continuous Pt film is more stable and has a 5-10 fold higher area-specific activity than Pt nanoparticles.1 This is only economically viable when the Pt film is less than ~3 nm thick.Pt ALD usually yields Pt nanoparticles during initial film growth. We have shown earlier in work on flat substrates that tungsten, with a higher surface energy than platinum (3.5 J/m2 vs 2.5 J/m2), can serve as an adhesion layer to achieve Pt ALD films that are dense and continuous at thicknesses of ~1.5 nm.2,3 To fabricate a practical electrocatalyst we developed a plasma-assisted, open-ended rotary reactor to deposit W and Pt ALD films on the high surface area metal oxide particles. We also deposited the layers on 3M NSTF substrate, an oriented organic crystalline substrate.Transmission electron microscopy (TEM) showed uniform and continuous ~3-5 nm Pt films on the TiO2 particles. The W ALD and Pt ALD films deposited on the 3M NSTF substrate were characterized using TEM with electron energy loss spectroscopy (EELS). The TEM-EELS analysis revealed W ALD and Pt ALD films with thicknesses of ~3 nm that were continuous and conformal on the high aspect ratio NSTF substrates. The production of these thin film on high surface area substrates demonstrates that it is possible to further reduce cost of fuel cell catalyst. Acknowledgements The authors thank Mark K. Debe, Edward M. Fischer, and Andrew Steinbach of 3M for providing non-platinized NSTF substrate. Thanks are also extended to Cristin Keary, Tom Moylan, and Peter Harvey for engineering support. References H. A. Gasteiger et al., Appl. Cat. B: Env. 56, 9 (2005).L. Baker et al., Appl. Phys. Lett. 101, 111601 (2012).US Patent 8,647,723.

Mesoporous aerogel titanium oxide–silicon oxide combinations as adsorbents for an azo-dye

This work investigates various high surface area metal oxide aerogels for the adsorption of a model pollutant, disperse red 19 (DR-19), under no irradiation and visible light irradiation. High surface area aerogels (200–490m2/g) adsorb a significantly higher percentage of the model pollutant than the commercially available TiO2 (51m2/g). Titanium dioxide–silicon dioxide high surface area aerogels combined with manganese or cobalt ions are shown to be more effective at sorption of the azo-dye than an undoped titanium oxide–silicon oxide aerogel, despite the higher surface area of the latter. Surface coverages, in molecules DR-19/nm2, are 0.18, 0.29, and 0.37 for a 10mg loading of TiO2–SiO2, TiO2–SiO2–Mn, and TiO2–SiO2–Co aerogels, respectively, under no irradiation. These numbers are shown to increase with decreased sorbent loading, decrease with increased sorbent loading, and remain unchanged with the same loading under visible light irradiation. These results suggest the adsorption of pollutants on titanium oxide–silicon oxides is dependent on both surface area and transition metal dopants. The presence of the manganese or cobalt ions enhances adsorption.

Sacrificial template synthesis of high surface area metal oxides. Example: An excellent structured Fenton-like catalyst

Standard sacrificial template synthesis allows metal oxide nanotubes to be produced from ZnO nanowires. In spite of their high interest in several technological fields, the low surface area of these nanotubes is a drawback for most applications. Here we report for the first time the sacrificial template synthesis of stainless steel wire-mesh (SSWM) supported metal oxides of high technological interest (CuO, CeO2, α-Fe2O3 and TiO2) with specific surface area values (84–275m2g−1) that are at least one order of magnitude higher than that of metal oxide nanotubes. The key to achieving this outstanding result was the use of a novel template (SSWM-supported ZnO nanosheets) with a large proportion of polar surfaces. As an example of application of these materials, a structured reactor with a highly active SSWM-supported α-Fe2O3 catalyst was successfully tested for the continuous Fenton-like degradation of aqueous Methylene blue.

Investigation of Modified Graphene for Energy Storage Applications

Lithium-ion batteries (LIB) have been receiving extensive attention because of the high specific energy density for wide applications such as electronic vehicles, commercial mobile electronics, and military applications. In LIB, graphite is the most commonly used anode material; however, lithium-ion intercalation in graphite is limited, hindering the battery charge rate and capacity. To overcome this obstacle, nanostructured anode assembly has been extensively studied to increase the lithium-ion diffusion rate. Among these approaches, high specific surface area metal oxide nanowires connecting nanostructured carbon materials accumulation have shown propitious results for enhanced lithium intercalation. Recently, nanowire/graphene hybrids were developed for the enhancement of LIB performance; however, almost all previous efforts employed nanowires on graphene in a random fashion, which limited lithium-ion diffusion rate. Therefore, we demonstrate a new approach by hydrothermally growing uniform nanowires on graphene aerogel to further improve the performance. This nanowire/graphene aerogel hybrid not only uses the high surface area of the graphene aerogel but also increases the specific surface area for electrode-electrolyte interaction. Therefore, this new nanowire/graphene aerogel hybrid anode material could enhance the specific capacity and charge-discharge rate. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used for materials characterization. Battery analyzer and potentio-galvanostat are used for measuring the electrical performance of the battery. The testing results show that nanowire graphene hybrid anode gives significantly improved performance compared to graphene anode.

Electrocatalytic oxidation of small organic molecules in acid medium: Enhancement of activity of noble metal nanoparticles and their alloys by supporting or modifying them with metal oxides

Different approaches to enhancement of electrocatalytic activity of noble metal nanoparticles during oxidation of small organic molecules (namely potential fuels for low-temperature fuel cells such as methanol, ethanol and formic acid) are described. A physical approach to the increase of activity of catalytic nanoparticles (e.g. platinum or palladium) involves nanostructuring to obtain highly dispersed systems of high surface area. Recently, the feasibility of enhancing activity of noble metal systems through the formation of bimetallic (e.g. PtRu, PtSn, and PdAu) or even more complex (e.g. PtRuW, PtRuSn) alloys has been demonstrated. In addition to possible changes in the electronic properties of alloys, specific interactions between metals as well as chemical reactivity of the added components have been postulated. We address and emphasize here the possibility of utilization of noble metal and alloyed nanoparticles supported on robust but reactive high surface area metal oxides (e.g. WO3, MoO3, TiO2, ZrO2, V2O5, and CeO2) in oxidative electrocatalysis. This paper concerns the way in which certain inorganic oxides and oxo species can act effectively as supports for noble metal nanoparticles or their alloys during electrocatalytic oxidation of hydrogen and representative organic fuels. Among important issues are possible changes in the morphology and dispersion, as well as specific interactions leading to the improved chemisorptive and catalytic properties in addition to the feasibility of long time operation of the discussed systems.

Cobalt(iii) complexes as functional ligands for metal (oxide) surfaces

Co(III) polyamine complexes with either two or three labile coordination sites bind strongly to high surface area metal oxides such as goethite or aluminium trihydroxide, and have been shown to act as passivating agents for aluminium flake in aqueous media, in addition to providing a potential method for surface functionalisation.

NiO(111) nanosheets as efficient and recyclable adsorbents for dye pollutant removal fromwastewater

Semiconductor single-crystalline polar NiO(111) nanosheets with well-defined hexagonalholes have been investigated for application in dye adsorption and combustion processes.With regard to adsorption technologies, high surface area metal oxides have an advantageover activated carbon in that the adsorbed species can be combusted and the adsorbentreused in the case of metal oxides while regeneration of activated carbon remainschallenging and thus the adsorbent/adsorbate system must be disposed of. Here,three typical textile dyes, reactive brilliant red X-3B, congo red and fuchsin red,were studied for removal from wastewater with two NiO systems and activatedcarbon. These studies revealed that the NiO(111) nanosheets exhibited muchmore favorable adsorptive properties than conventionally prepared nickel oxidepowder (CP-NiO) obtained from thermal decomposition of nickel nitrate. Themaximum adsorption capabilities of the three dyes on NiO(111) nanosheets reached30.4 mg g−1,35.15 mg g−1 and22 mg g−1 for reactive brilliant red X-3B, congo red and fuchsin acid, respectively, while themaximum adsorption capabilities of the three dyes on CP-NiO were only 8.4, 13.2 and12 mg g−1 for reactive brilliant red X-3B, congo red and fuchsin acid. To simulate the adsorptionisotherm, two commonly employed models, the Langmuir and the Freundlich isotherms, wereselected to explicate the interaction of the dye and NiO(111). The isotherm evaluationsrevealed that the Langmuir model demonstrated better fit to experimental equilibrium datathan the Freundlich model. The maximum predicted adsorption capacity was 36.1 mg g−1. In addition, adsorption kinetic data of NiO(111) followed a pseudo-second-order rate forcongo red. These studies infer that NiO(111) nanosheets possess desirable properties forapplication in adsorption and combustion applications.

Aqueous synthesis of high surface area metal oxides

By applying high throughput synthesis and characterization technologies, we have been optimizing common dry or aqueous synthetic routes for the preparation of high surface area metals and oxides, such as precipitation and modified Pechini methods. For wet combustion synthesis, we have been screening a variety of organic acids as dispersants and developed proprietary recipes for individual metals. By resorting to easily decomposable organic acids (as opposed to citric acid in the original Pechini combustion method), such as glyoxylic acid, oxalacetic acid and ketoglutaric acid, it is possible to obtain high surface area materials for many metals after careful optimization of acid/metal ratio and calcination conditions. Examples are Sn, In, Co, Ru, Ni, Fe, Mn, Y, Ce and Rare Earth oxides and their mixtures. After calcination in the temperature range of about 300–400 °C, surface areas >150 m 2/g could be obtained for Er, Tm, Co, Ru, and Nb; >200 m 2/g for Sn, Fe, Mn, and Y; >300 m 2/g for Ce; and >400 m 2/g for Ni oxide. Noteworthy are also >140 m 2/g for La 2O 3, >80 m 2/g for CuO, and 75 m 2/g for ZnO. For V, around 40 m 2/g was possible for the nearly carbon-free V 2O 5, whereas up to 90 m 2/g was obtained for a 90% V–10% carbon composite (by incomplete combustion of the organic acid). Residual carbon helps in stabilizing the porous oxide against sintering. Thus, conventional aqueous routes (precipitation, Pechini) can be competitive to more elaborate and costly methods such as those using organic solvents, sol–gel, supercritical drying or template/hydrothermal synthesis. Combustion synthesis is well suited for the preparation of mixed oxides from mixed metal solutions in aqueous organic acids. Bulk porous Co and CoRu mixed oxides have been screened for liquid phase alcohol oxidations and CoRuCe oxides for CO oxidation and VOC destruction, and doped NiO has been reduced to the metal and tested for various hydrogenations.

Anodic Aluminum Oxide Templated Channel Electrodes via Atomic Layer Deposition

Dye-sensitized solar cells (DSSCs) utilize high surface area metal oxide sintered particle networks to absorb molecular dyes and transport injected charge carriers. While this sintered particle architecture allows liquid electrolyte DSSCs to achieve efficiencies up to 11%, slow charge transport through the semiconductor network limits the amount of modification that can be made to the electrolyte and dye without adversely affecting the efficiency. The functionalization of anodic aluminum oxide membranes with thin films of transparent, semiconducting oxides via atomic layer deposition may allow for significantly faster charge transport. We demonstrate the fabrication of ZnO thin films within and upon commercially available anodic aluminum oxide membranes via atomic layer deposition.