A device for measuring surface potentials of individual crystal planes was constructed. The surface potentials of the (0 1 2), (1 0 -2), (1 1 3), and (1 1 -3) crystal planes of hematite were measured as a function of pH at different sodium nitrate concentrations. Results of measurement enabled differentiation between the planes, showing agreement with the surface potentials obtained with a single-crystal hematite electrode. At low ionic strength there was no significant difference in potential between the crystal planes, whereas at relatively high ionic strength the difference was noticeable. In the absence of counterion association, but also in the case of their symmetric association taking place, point of zero potential (pH(pzp)) coincides with other zero points, i.e., with the isolectric point (pH(iep)) and the point of zero charge (pH(pzc)). If the counterion affinities toward association are not equal, the pH(pzp) is shifted in the same directions as the pH(pzc). The shift in the point of zero potential to the basic region was more pronounced for the (1 1 -3) plane than for the (1 0 -2) one, indicating a higher affinity of anions for association with oppositely charged surface groups compared to cations. It was demonstrated that measurements of surface potentials of individual crystal planes could help to better understand the equilibrium at solid/liquid interfaces.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jcis.2007.09.090 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Carboxylated cellulose nanocrystals mediated flower-like zinc oxide for antimicrobial without activation of light.
J Colloid Interface Sci
April 2025
State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China. Electronic address:
Conventional light-driven antimicrobial strategies of zinc oxide (ZnO) are limited by inadequate illumination in dark environments. In this study, carboxylated cellulose nanocrystals (MCNC) mediated flower-like ZnO (C@Z) with self-promoted reactive oxygen species release under dark is fabricated. The adsorption of Zn ions on MCNC prompts the growth of ZnO along the (002) crystal plane, forming a flower-like hybrid with superior dispersibility and oxygen vacancies compared to MCNC-free ZnO, which exposes the (100) plane.
View Article and Find Full Text PDFSnHPO: A Layered Tin(II) Phosphate with Enhanced Birefringence.
Inorg Chem
January 2025
College of Physics, Qingdao University, National Demonstration Center for Experiment Applied Physics Education (Qingdao University), Qingdao Broadband Terahertz Spectroscopy Technology Engineering Research Center (Qingdao University), Qingdao 266071, China.
As promising optoelectronic functional materials in the short-wavelength spectral region, such as ultraviolet (UV) and deep UV, phosphates have recently received increased attention. However, phosphate materials commonly suffer from limited birefringence owing to the highly symmetrical PO tetrahedra. We herein report a layered tin(II) phosphate with improved birefringence.
View Article and Find Full Text PDFCrystallographic Spin Torque Conductivity Tensor of Epitaxial IrO Thin Films for Oxide Spintronics.
Adv Mater
January 2025
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin, 53706, USA.
Unconventional spin-orbit torques arising from electric-field-generated spin currents in anisotropic materials have promising potential for spintronic applications, including for perpendicular magnetic switching in high-density memory applications. Here, all the independent elements of the spin torque conductivity tensor allowed by bulk crystal symmetries for the tetragonal conductor IrO are determined via measurements of conventional (in-plane) anti-damping torques for IrO thin films in the high-symmetry (001) and (100) orientations. It is then tested whether rotational transformations of this same tensor can predict both the conventional and unconventional anti-damping torques for IrO thin films in the lower-symmetry (101), (110), and (111) orientations, finding good agreement.
View Article and Find Full Text PDFExploring Tetra-/Penta-/Hexavalent Ion Substitution in Yttrium-Based Halide Solid-State Electrolytes.
Nano Lett
January 2025
Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin 300350, P.R. China.
Although aliovalent ion substitution is an important strategy for enhancing ionic conductivity in halide electrolytes, the choice of doping ions is often restricted to tetravalent ions, and investigations into the intrinsic origin of the doping mechanism are lacking. In this work, we investigated the effects of Zr, Ta and W doping on the crystal structure and ionic conductivity of yttrium-based rare-earth halides. Only Zr achieves fast ion diffusion in both the (001) and (002) crystal planes by affecting the volume of the octahedron and the tetrahedral interstitial space, whereas Ta significantly enhances the ion diffusion rate in the (001) crystal plane while suppressing it in the (002) plane, and W does the opposite.
View Article and Find Full Text PDFConformational flexibility of human ribokinase captured in seven crystal structures.
Int J Biol Macromol
January 2025
Department of Biochemistry, Memorial University of Newfoundland, 45 Arctic Avenue, St. John's, Newfoundland and Labrador, Canada. Electronic address:
d-ribose is a critical sugar substrate involved in the biosynthesis of nucleotides, amino acids, and cofactors, with its phosphorylation to ribose-5-phosphate by ribokinase (RK) constituting the initial step in its metabolism. RK is conserved across all domains of life, and its activity is significantly enhanced by monovalent metal (M) ions, particularly K, although the precise mechanism of this activation remains unclear. In this study, we present several crystal structures of human RK in both unliganded and substrate-bound states, offering detailed insights into its substrate binding process, reaction mechanism, and conformational changes throughout the catalytic cycle.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!