@article{hamilton_o'donnell_zoellner_sullivan_maggard_2020, title={Flux‐mediated synthesis and photocatalytic activity of NaNbO
            3
            particles}, volume={103}, ISSN={0002-7820 1551-2916}, url={http://dx.doi.org/10.1111/jace.16765}, DOI={10.1111/jace.16765}, abstractNote={Abstract}, number={1}, journal={Journal of the American Ceramic Society}, publisher={Wiley}, author={Hamilton, Adam M. and O'Donnell, Shaun and Zoellner, Brandon and Sullivan, Ian and Maggard, Paul A.}, year={2020}, month={Jan}, pages={454–464} }
 @article{batra_tran_johnson_zoellner_maggard_jones_rossetti_ramprasad_2020, title={Search for Ferroelectric Binary Oxides: Chemical and Structural Space Exploration Guided by Group Theory and Computations}, volume={32}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.9b05324}, abstractNote={The presence of bistable polarization states along with accessible switching capabilities lend ferroelectrics as the ideal candidates for a variety of applications. Although many conventional ferro...}, number={9}, journal={CHEMISTRY OF MATERIALS}, author={Batra, Rohit and Tran, Huan Doan and Johnson, Brienne and Zoellner, Brandon and Maggard, Paul A. and Jones, Jacob L. and Rossetti, George A., Jr Jr and Ramprasad, Rampi}, year={2020}, month={May}, pages={3823–3832} }
 @article{zoellner_o'donnell_wu_itanze_carbone_osterloh_geyer_maggard_2019, title={Impact of Nb(V) Substitution on the Structure and Optical and Photoelectrochemical Properties of the Cu-5(Ta1-xNbx)(11)O-30 Solid Solution}, volume={58}, ISSN={["1520-510X"]}, DOI={10.1021/acs.inorgchem.9b00304}, abstractNote={A family of solid solutions, Cu5(Ta1- xNb x)11O30 (0 ≤ x ≤ 0.4), was investigated as p-type semiconductors for their band gaps and energies and for their activity for the reduction of water to molecular hydrogen. Compositions from 0 to 40 mol % niobium were prepared in high purity by solid-state methods, accompanied by only very small increases in the lattice parameters of ∼0.05% and with the niobium and tantalum cations disordered over the same atomic sites. However, an increasing niobium content causes a significant decrease in the bandgap size from ∼2.58 to ∼2.05 eV owing to the decreasing conduction band energies. Linear-sweep voltammetry showed an increase in cathodic photocurrents with niobium content and applied negative potential of up to -0.6 mA/cm2 (pH ∼7.3; AM 1.5 G light filter with an irradiation intensity of ∼100 mW/cm2). The cathodic photocurrents could be partially stabilized by heating the polycrystalline films in air at 550 °C for 1 h to produce surface nanoislands of CuO or using protecting layers of aluminum-doped zinc oxide and titania. Aqueous suspensions of the Cu5(Ta1- xNb x)11O30 powders were also found to be active for hydrogen production under visible-light irradiation in a 20% aqueous methanol solution with the highest apparent quantum yields for the 10% and 20% Nb-substituted samples. Electronic structure calculations show that the increased photocurrents and hydroen evolution activities of the solid solutions arise near the percolation threshold of the niobate/tantalate framework wherein the Nb cations establish an extended -O-Nb-O-Nb-O- diffusion pathway for the minority carriers. The latter also reveals a novel pathway for enhancing charge separation as a function of the niobium-oxide connectivity. Thus, these results illustrate the advantages of using solid solutions to achieve the smaller bandgap sizes and band energies that are needed for solar-driven photocatalytic reactions.}, number={10}, journal={INORGANIC CHEMISTRY}, author={Zoellner, Brandon and O'Donnell, Shaun and Wu, Zongkai and Itanze, Dominique and Carbone, Abigail and Osterloh, Frank E. and Geyer, Scott and Maggard, Paul A.}, year={2019}, month={May}, pages={6845–6857} }
 @article{kumar_o'donnell_zoellner_martinez_wang_maggard_2019, title={Interfacing Plasmonic Nanoparticles with Ferroelectrics for Hot-Carrier-Driven Photocatalysis: Impact of Schottky Barrier Height}, volume={2}, ISSN={["2574-0962"]}, DOI={10.1021/acsaem.9b01682}, abstractNote={Emergent strategies for efficient solar energy conversion have focused on ways to harness photons in the lower-energy range of sunlight that cannot be utilized by conventional semiconductor photocatalyst systems. Recent research has demonstrated that interfaced plasmonic–ferroelectric particles represent a promising strategy for the utilization of near-infrared (NIR) light owing to the possibility of the more efficient injection of hot charge carriers from noble metal nanoparticles. Described herein, platinum-end-capped gold nanorods (AuNRs) function as antennae to absorb low-energy NIR photons to generate hot electrons that can be injected into ferroelectric PbZrxTi1–xO3 (PZT; x = 0.48, 0.50, 0.52, 0.54, 0.56, and 0.60) and drive the reduction of water to molecular hydrogen at its surfaces. As an aqueous suspension, the interfaced AuNR-PZT particles exhibited maximal photocatalytic rates for hydrogen formation under a 976 nm diode laser (powder density = 2.0 W cm–2) for the 52% Zr (x = 0.52) composition ...}, number={10}, journal={ACS APPLIED ENERGY MATERIALS}, author={Kumar, Vineet and O'Donnell, Shaun and Zoellner, Brandon and Martinez, Jhon and Wang, Gufeng and Maggard, Paul A.}, year={2019}, month={Oct}, pages={7690–7699} }
 @article{zoellner_hou_carbone_kiether_markham_cuomo_maggard_2018, title={Activating the Growth of High Surface Area Alumina Using a Liquid Galinstan Alloy}, volume={3}, ISSN={["2470-1343"]}, DOI={10.1021/acsomega.8b02442}, abstractNote={The growth of high surface area alumina has been investigated with the use of a liquid Galinstan alloy [66.5% (wt %) Ga, 20.5% In and 13.0% Sn] as an activator for aluminum. In this process, the aluminum is slowly dissolved into the gallium-indium-tin alloy, which is then selectively oxidized at ambient temperature and pressure under a humid stream of flowing CO2 or N2 to yield amorphous alumina. This preparative route represents a simple and low toxicity approach to obtain amorphous high surface area alumina with very low water content. The as-synthesized high surface area alumina aerogel was a blue-colored solid owing to the Rayleigh scattering by its dendritic fibrous nanostructure consisting of mainly alumina with small amounts of water. Upon annealing at 850 °C, the amorphous product transformed into γ-Al2O3, as well as θ-Al2O3 upon annealing at 1050 °C. Elemental analysis by energy-dispersive spectroscopy provides further evidence that the high surface area alumina is composed of only aluminum and oxygen. The surface area of the amorphous alumina varied from ∼79 to ∼140 m2/g, depending on the initial weight percentage of aluminum used in the alloy. A correlation between the initial concentration of aluminum in the alloy and the surface area of the alumina product was found to peak at ∼30% Al. These results suggest a novel route to the formation of amorphous alumina aerogel-type materials.}, number={12}, journal={ACS OMEGA}, author={Zoellner, Brandon and Hou, Feier and Carbone, Abigail and Kiether, William and Markham, Keith and Cuomo, Jerome and Maggard, Paul A.}, year={2018}, month={Dec}, pages={16409–16415} }
 @article{ortiz_zoellner_kumar_janelli_tang_maggard_wang_2018, title={Composite Ferroelectric and Plasmonic Particles for Hot Charge Separation and Photocatalytic Hydrogen Gas Production}, volume={1}, ISSN={["2574-0962"]}, DOI={10.1021/acsaem.8b00772}, abstractNote={Plasmonic nanoparticles are excellent light absorbers for harvesting solar energy, resulting in hot electrons that can be utilized in photocatalytic hydrogen production. However, the hot electrons generated in a localized surface plasmon resonance process have a very short lifetime and are challenging to use efficiently. Herein, using near IR light irradiation, we show that by combining gold nanorods (AuNRs) with ferroelectric PbTiO3 particles that possess a large remanent electric dipole moment, hot charges generated on plasmonic particles can be injected into ferroelectric materials and drive the photocatalysis reaction. Compared to metallic Pt-end-capped AuNRs, the efficiency of using hot electrons for photocatalytic reactions is enhanced for the composite catalyst, which improves the light-to-chemical energy conversion efficiencies by about 1 order of magnitude for the same amount of plasmonic particles being used.}, number={9}, journal={ACS APPLIED ENERGY MATERIALS}, author={Ortiz, Nathalia and Zoellner, Brandon and Kumar, Vineet and Janelli, Tara and Tang, Shuli and Maggard, Paul A. and Wang, Gufeng}, year={2018}, month={Sep}, pages={4606–4616} }
 @article{kumar_zoellner_maggard_wang_2018, title={Effect of doping Ge into Y2O3:Ho,Yb on the green-to-red emission ratio and temperature sensing}, volume={47}, ISSN={["1477-9234"]}, DOI={10.1039/c8dt02216j}, abstractNote={The Ge-doped Y2O3:Ho,Yb phosphor tunes the G/R ratio, and the G/R ratio has a higher absolute temperature sensitivity.}, number={32}, journal={DALTON TRANSACTIONS}, author={Kumar, Vineet and Zoellner, Brandon and Maggard, Paul A. and Wang, Gufeng}, year={2018}, month={Aug}, pages={11158–11165} }
 @article{zoellner_gordon_maggard_2017, title={A small bandgap semiconductor, p-type MnV2O6, active for photocatalytic hydrogen and oxygen production}, volume={46}, ISSN={["1477-9234"]}, DOI={10.1039/c7dt00780a}, abstractNote={Visible-light active MnV2O6 with suitable band positions for both water oxidation and reduction.}, number={32}, journal={DALTON TRANSACTIONS}, author={Zoellner, Brandon and Gordon, Elijah and Maggard, Paul A.}, year={2017}, month={Aug}, pages={10657–10664} }
 @article{ortiz_zoellner_hong_jo_wang_liu_maggard_wang_2017, title={Harnessing Hot Electrons from Near IR Light for Hydrogen Production Using Pt-End-Capped-AuNRs}, volume={9}, ISSN={["1944-8244"]}, DOI={10.1021/acsami.7b05064}, abstractNote={Gold nanorods show great potential in harvesting natural sunlight and generating hot charge carriers that can be employed to produce electrical or chemical energies. We show that photochemical reduction of Pt(IV) to Pt metal mainly takes place at the ends of gold nanorods (AuNRs), suggesting photon-induced hot electrons are localized in a time-averaged manner at AuNR ends. To use these hot electrons efficiently, a novel synthetic method to selectively overgrow Pt at the ends of AuNRs has been developed. These Pt-end-capped AuNRs show relatively high activity for the production of hydrogen gas using artificial white light, natural sunlight, and more importantly, near IR light at 976 nm. Tuning of the surface plasmon resonance (SPR) wavelength of AuNRs changes the hydrogen gas production rate, indicating that SPR is involved in hot electron generation and photoreduction of hydrogen ions. This study shows that gold nanorods are excellent for converting low-energy photons into high-energy hot electrons, which can be used to drive chemical reactions at their surfaces.}, number={31}, journal={ACS APPLIED MATERIALS & INTERFACES}, author={Ortiz, Nathalia and Zoellner, Brandon and Hong, Soung Joung and Jo, Yue and Wang, Tao and Liu, Yang and Maggard, Paul A. and Wang, Gufeng}, year={2017}, month={Aug}, pages={25962–25969} }
 @misc{sullivan_zoellner_maggard_2016, title={Copper(I)-Based p-Type Oxides for Photoelectrochemical and Photovoltaic Solar Energy Conversion}, volume={28}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.6b00926}, abstractNote={Recent research efforts have been growing into p-type copper(I) based oxides for development of their use in solar energy applications. The oxides of interest include the binary Cu2O and a number of new ternary CuxMyOz oxides. Both the binary and ternary Cu(I)-based oxides have many advantages when compared to other well-known p-type oxides such as NiO, III–V, and II–VI semiconductors. The benefits found within the diverse group of Cu(I)-containing oxides include bandgap sizes that can be tuned from ∼1.2 to >3.0 eV, high charge carrier mobility, and favorable band energies relative to fuel-producing redox couples. These properties give them potential utility in a variety of different solar applications, such as in dye-sensitized solar cells and suspended powder photocatalysis. Research efforts into surface modifications and changes in their chemical compositions and structures have allowed for greater stability and greater efficiency in aqueous solutions, both of which have represented two key barriers fo...}, number={17}, journal={CHEMISTRY OF MATERIALS}, author={Sullivan, Ian and Zoellner, Brandon and Maggard, Paul A.}, year={2016}, month={Sep}, pages={5999–6016} }
 @article{zoellner_stuart_chung_dougherty_jones_maggard_2016, title={CuNb1−xTaxO3 (x ≤ 0.25) solid solutions: impact of Ta(v) substitution and Cu(i) deficiency on their structure, photocatalytic, and photoelectrochemical properties}, volume={4}, ISSN={2050-7488 2050-7496}, url={http://dx.doi.org/10.1039/c5ta06609c}, DOI={10.1039/c5ta06609c}, abstractNote={Investigation of CuNb1−xTaxO3has led to new insights into the visible-light photocurrents and photocatalytic activities of solid solutions.}, number={8}, journal={Journal of Materials Chemistry A}, publisher={Royal Society of Chemistry (RSC)}, author={Zoellner, Brandon and Stuart, Sean and Chung, Ching-Chang and Dougherty, Daniel B. and Jones, Jacob L. and Maggard, Paul A.}, year={2016}, pages={3115–3126} }
 @article{boltersdorf_sullivan_shelton_wu_gray_zoellner_osterloh_maggard_2016, title={Flux Synthesis, Optical and Photocatalytic Properties of n-type Sn2TiO4: Hydrogen and Oxygen Evolution under Visible Light}, volume={28}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.6b02003}, abstractNote={The n-type Sn2TiO4 phase was synthesized using flux methods and found to have one of the smallest visible-light bandgap sizes known that also maintains suitable conduction and valence band energies for driving photocatalytic water-splitting reactions. The Sn2TiO4 phase was synthesized using either a SnCl2 flux or a SnCl2/SnF2 peritectic flux in a 2:1 flux-to-precursor ratio heated at 600 and 400 °C for 24 h, respectively. The two types of salt fluxes resulted in large rod-shaped particles at 600 °C and smaller tetragonal prism-shaped particles at 400 °C. Surface photovoltage spectroscopy measurements produced a negative photovoltage under illumination >1.50 eV, which confirmed electrons as the majority charge carriers and ∼1.50 eV as the effective band gap. Mott–Schottky measurements at pH 9.0 showed the conduction (−0.54 V vs NHE) and valence band (+1.01 V vs NHE) positions meet the critical thermodynamic requirements for total water splitting. The Sn2TiO4 particles were deposited and annealed as polycry...}, number={24}, journal={CHEMISTRY OF MATERIALS}, author={Boltersdorf, Jonathan and Sullivan, Ian and Shelton, Timothy L. and Wu, Zongkai and Gray, Matthew and Zoellner, Brandon and Osterloh, Frank E. and Maggard, Paul A.}, year={2016}, month={Dec}, pages={8876–8889} }
 @article{boltersdorf_zoellner_fancher_jones_maggard_2016, title={Single- and Double-Site Substitutions in Mixed-Metal Oxides: Adjusting the Band Edges Toward the Water Redox Couples}, volume={120}, ISSN={["1932-7455"]}, DOI={10.1021/acs.jpcc.6b05758}, abstractNote={New mixed-metal oxide solid solutions, i.e., the single-metal substituted Na2Ta4–yNbyO11 (0 ≤ y ≤ 4) and the double-metal substituted Na2–2xSnxTa4–yNbyO11 (0 ≤ y ≤ 4; 0 ≤ x ≤ 0.35), were investigated and used to probe the impact of composition on their crystalline structures, optical band gaps, band energies, and photocatalytic properties. The Na2Ta4O11 (y = 1) phase was prepared by flux-mediated synthesis, while the members of the Na2Ta4–yNbyO11 solid solution (1 ≤ y ≤ 4) were prepared by traditional high-temperature reactions. The Sn(II)-containing Na2–2xSnxTa4–yNbyO11 (0 ≤ y ≤ 4) solid solutions were prepared by flux-mediated ion-exchange reactions of the Na2Ta4–yNbyO11 solid solutions within a SnCl2 flux. The crystalline structures of both solid solutions are based on the parent Na2B4O11 (B = Nb, Ta) phases and consist of layers of edge-shared BO7 pentagonal bipyramids that alternate with layers of isolated BO6 octahedra surrounded by Na(I) cations. Rietveld refinements of the Na2Ta4–yNbyO11 solid sol...}, number={34}, journal={Journal of Physical Chemistry C}, author={Boltersdorf, J. and Zoellner, B. and Fancher, C. and Jones, J. and Maggard, P.A.}, year={2016}, month={Aug}, pages={19175–19188} }
 @article{skorupska_maggard_eichberger_schwarzburg_shahbazi_zoellner_parkinson_2015, title={Combinatorial Investigations of High Temperature CuNb Oxide Phases for Photoelectrochemical Water Splitting}, volume={17}, ISSN={["2156-8944"]}, DOI={10.1021/acscombsci.5b00142}, abstractNote={High-throughput combinatorial methods have been useful in identifying new oxide semiconductors with the potential to be applied to solar water splitting. Most of these techniques have been limited to producing and screening oxide phases formed at temperatures below approximately 550 °C. We report the development of a combinatorial approach to discover and optimize high temperature phases for photoelectrochemical water splitting. As a demonstration material, we chose to produce thin films of high temperature CuNb oxide phases by inkjet printing on two different substrates: fluorine-doped tin oxide and crystalline Si, which required different sample pyrolysis procedures. The selection of pyrolysis parameters, such as temperature/time programs, and the use of oxidizing, nonreactive or reducing atmospheres determines the composition of the thin film materials and their photoelectrochemical performance. XPS, XRD, and SEM analyses were used to determine the composition and oxidation states within the copper niobium oxide phases and to then guide the production of target Cu(1+)Nb(5+)-oxide phases. The charge carrier dynamics of the thin films produced by the inkjet printing are compared with pure CuNbO3 microcrystalline material obtained from inorganic bulk synthesis.}, number={12}, journal={ACS COMBINATORIAL SCIENCE}, author={Skorupska, Katarzyna and Maggard, Paul A. and Eichberger, Rainer and Schwarzburg, Klaus and Shahbazi, Paria and Zoellner, Brandon and Parkinson, Bruce A.}, year={2015}, month={Dec}, pages={742–751} }
 @article{sahoo_zoellner_maggard_2015, title={Optical, electronic, and photoelectrochemical properties of the p-type Cu3-xVO4 semiconductor}, volume={3}, ISSN={["2050-7496"]}, DOI={10.1039/c4ta04876h}, abstractNote={Formation of surface nanoparticles on p-type Cu3VO4 (shown) and their critical role in enhancing its photocurrents for solar energy conversion.}, number={8}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, author={Sahoo, Prangya P. and Zoellner, Brandon and Maggard, Paul A.}, year={2015}, pages={4501–4509} }