Paul A. Maggard

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTUnderstanding the Role of Helical Chains in the Formation of Noncentrosymmetric SolidsPaul A. Maggard, Charlotte L. Stern, and Kenneth R. PoeppelmeierView Author Information Department of Chemistry Northwestern University Evanston, Illinois 60208-3113 Cite this: J. Am. Chem. Soc. 2001, 123, 31, 7742–7743Publication Date (Web):July 11, 2001Publication History Received20 April 2001Revised15 June 2001Published online11 July 2001Published inissue 1 August 2001https://pubs.acs.org/doi/10.1021/ja016055yhttps://doi.org/10.1021/ja016055yrapid-communicationACS PublicationsCopyright © 2001 American Chemical SocietyRequest reuse permissionsArticle Views1158Altmetric-Citations268LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Anions,Cations,Crystal structure,Ligands,Pyrazine Get e-Alerts

Synthesis of SrTiO3-coated BiFeO3 (see Figure) and Fe2O3 metal-oxide particles has been performed using low-temperature hydrothermal techniques. The coated materials suggest a promising new and general strategy for the sensitization of UV-active metal oxide photocatalysts to visible light.

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 for this class of materials. Presented in this review are the currently known binary and ternary Cu(I)-oxides and relationships of their syntheses and structures with their visible-light and ultraviolet bandgap sizes, band energies, and photoelectrochemical properties. As their constituent elements are relatively abundant and nontoxic, they represent an attractive class of materials that can be used in the conversion of sunlight to electricity or solar fuels.

Three new silver-vanadate hybrid solids, [Ag(bpy)]4V4O12 x 2 H2O (I), [Ag(dpa)]4V4O12 x 4 H2O (II), and Ag4(pzc)2V2O6 (III) (bpy = 4,4'-bipyridine, dpa = 1,2-bis(4-pyridyl)-ethane, pzc = pyrazinecarboxylate), were synthesized by hydrothermal methods and characterized using single crystal X-ray diffraction (I, P2(1)/c, Z = 4, a = 11.375(2) A, b = 14.281(4) A, c = 13.598(3) A, beta = 91.46(1) degrees; II, P2(1)/c, Z = 8, a = 13.5748(3) A, b = 15.3372(4) A, c = 14.1854(3) A, beta = 114.1410(9) degrees; III, P1, Z = 2, a = 3.580(1) A, b = 11.839(4) A, c = 19.321(7) A, alpha = 89.110(7) degrees, beta = 87.719(9) degrees, gamma = 86.243(8) degrees), thermogravimetric analysis, and UV-vis diffuse reflectance. The structures of I and II are constructed from neutral {Ag4V4O12}n layers of clusters that are pillared via the coordination of organic ligands (bpy for I and dpa for II) to the Ag sites in each layer. Conversely, the structure of III is composed of a three-dimensional {Ag2(pzc)(+)}n coordination network with channels containing {VO3(-)}n chains. The lattice water molecules can be removed upon heating to > or = 180 degrees C for I (reversibly) and to > or = 120 degrees C for II (irreversibly). All three decompose with the removal of organic ligands at higher temperatures of > 200-300 degrees C. Their optical bandgap sizes were measured to be 2.77 eV for I, 2.95 eV for II, and 2.45 eV for III, which decrease most notably as a result of the band widening for the more extended vanadate structure in III. All three hybrid solids are photocatalytically active for the decomposition of methylene blue under UV light (lambda < 400 nm; 1.01, 0.64, and 2.65 mg L(-1) h(-1) for I, II, and III, respectively), while only III exhibits a high activity under visible-light irradiation (lambda > 400 nm; 1.20 mg L(-1) h(-1) ). These new hybrid solids are among the first reported to exhibit high photocatalytic activities under either ultraviolet or visible-light irradiation and have also been analyzed with respect to the effect of the different organic ligands on their atomic- and electronic-structures.