Search

Spectator ions have known and emerging roles in aqueous metal-cation chemistry, respectively directing solubility, speciation, and reactivity. Here, we isolate and structurally characterize the last two metastable members of the alkali uranyl triperoxide series, the Rb+ and Cs+ salts (Cs-U1 and Rb-U1). We document their rapid solution polymerization via small-angle X-ray scattering, which is compared to the more stable Li+, Na+ and K+ analogues. To understand the role of the alkalis, we also quantify alkali-hydroxide promoted peroxide deprotonation and decomposition, which generally exhibits increasing reactivity with increasing alkali size. Cs-U1, the most unstable of the uranyl triperoxide monomers, undergoes ambient direct air capture of CO2 in the solid-state, converting to Cs4[UVIO2(CO3)3], evidenced by single-crystal X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. We have attempted to benchmark the evolution of Cs-U1 to uranyl tricarbonate, which involves a transient, unstable hygroscopic solid that contains predominantly pentavalent uranium, quantified by X-ray photoelectron spectroscopy. Powder X-ray diffraction suggests this intermediate state contains a hydrous derivative of CsUVO3, where the parent phase has been computationally predicted, but not yet synthesized.

Luminescent materials with tunable emission are becoming increasingly desirable as we move towards needing efficient Light Emitting Diodes (LEDs) for displays. Key to developing better displays is the advancement of strategies for rationally designing emissive materials that are tunable and efficient. We report a series of emissive metal-organic frameworks (MOFs) generated using BUT-10 (BUT: Beijing University of Technology) that emits green light with λmax at 525 nm. Post-synthetic reduction of the ketone on the fluorenone ligand in BUT-10 generates new materials, BUT-10-M and BUT-10-R. The emission for BUT-10-R is hypsochromically-shifted by 113 nm. Multivariate BUT-10-M structures demonstrate emission with two maxima corresponding to the emission of both fluorenol and fluorenone moieties present in their structures. Our study represents a novel post-synthetic ligand reduction strategy for producing emissive MOFs with tunable emission ranging from green, white-blue to deep blue.

The interactions between charge carriers and electrode structures represent one of the most important considerations in the search for new energy storage devices. Currently, ionic bonding dominates the battery chemistry. Here we report the reversible insertion of a large molecular dication, methyl viologen, into the crystal structure of an aromatic solid electrode, 3,4,9,10-perylenetetracarboxylic dianhydride. This is the largest insertion charge carrier when non-solvated ever reported for batteries; surprisingly, the kinetic properties of the (de)insertion of methyl viologen are excellent with 60% of capacity retained when the current rate is increased from 100 mA g-1 to 2000 mA g-1. Characterization reveals that the insertion of methyl viologen causes phase transformation of the organic host, and embodies guest-host chemical bonding. First-principles density functional theory calculations suggest strong guest-host interaction beyond the pure ionic bonding, where a large extent of covalency may exist. This study extends the boundary of battery chemistry to large molecular ions as charge carriers and also highlights the electrochemical assembly of a supramolecular system.

Photocatalytic hydrogen production offers an alternative pathway to establish a sustainable energy economy, utilizing the Earth's natural sunlight and water resources to address environmental concerns associated with fossil fuel combustion. While numerous photoactive materials exhibit high potential for generating hydrogen from water, the synergy achieved by combining two different materials with complementary properties in the form of heterojunctions can significantly enhance the rate of hydrogen production and quantum efficiency. Our study describes the design and generation of the metal–organic framework‐derived (MOF) metal oxide heterojunction herein referred to as RTTA, composed of RuO2/N,S‐TiO2. The RuO2/N,S‐TiO2 is generated through the pyrolysis of MOFs, Ru‐HKUST‐1, and the amino‐functionalized MIL‐125‐NH2 in the presence of thiourea. Among the various RTTA materials tested, RTTA‐1, characterized by the lowest RuO2 content, exhibited the highest hydrogen evolution rate, producing 10,761 μmol ⋅ hr−1 ⋅ g−1 of hydrogen with an apparent quantum yield of 10.0 % in pure water containing glycerol. In addition to RTTA‐1, we generated two other MOF‐derived metal oxide heterojunctions, namely ZTTA‐1 (ZnO/N,S‐TiO2) and ITTA‐1 (In2O3/N,S‐TiO2). These heterojunctions were tested for their photocatalytic activity, leading to apparent quantum yields of 0.7 % and 0.3 %, respectively. The remarkable photocatalytic activity observed in RTTA‐1 is thought to be attributed to the synergistic effects arising from the combination of metallic properties inherent in the metal oxides, complemented by the presence of suitable band alignment, porosity, and surface properties inherited from the parent MOFs. These properties enhance electron transfer and restrict hole movement. The photocatalytic efficiency of RTTA‐1 was further demonstrated in actual water samples, producing hydrogen with a rate of 8,190 μmol ⋅ hr−1 ⋅ g−1 in tap water, and 6,390 μmol ⋅ hr−1 ⋅ g−1 in river water. [ABSTRACT FROM AUTHOR]

For the first time, we demonstrate that orthorhombic V2O5 can exhibit superior electrochemical performance in sodium ion batteries when uniformly coated inside nanoporous carbon. The encapsulated V2O5 shows a specific capacity as high as 276 mAh/g, while the whole nanocomposite exhibits a capacity of 170 mAh/g. The V2O5/C composite was fabricated by a novel ambient hydrolysis deposition that features sequential water vapor adsorption in nanoporous carbon, followed by a hydrolysis reaction, exclusively inside the nanopores. The unique structure of the nanocomposite significantly enhances the capacity as well as the rate performance of orthorhombic V2O5 where the composite retains a capacity of over 90 mAh/g at a current rate of 640 mA/g. Furthermore, by calculating, we also revealed that a large portion of the sodium-ion storage, particularly at high current rates, is due to the V2O5 pseudocapacitance.

Hard x-ray photoelectron spectroscopy using monochromatic Cr Kα radiation (5414.8 eV) has been used to acquire XPS and Auger data on sputtered In, Sn, and ITO samples. Survey data, high-resolution scans of all observed photoelectron peaks, and high-resolution scans of Auger lines are presented herein. [ABSTRACT FROM AUTHOR]

This document is an erratum for a published paper titled "HAXPES reference spectra of CeO2 with Cr Kα excitation." It corrects an error in the second author affiliation and updates the spectral features table by removing the incorrect identification of the Ce 4p1/2 peak. The document also includes a table of Auger transition peak energies for various elements, providing the element symbol, specific Auger transition, peak energy reported as kinetic energy, and the authors of the report. The authors emphasize that the Auger transition peak energies are reported as kinetic energy. [Extracted from the article]

Hard x-ray photoelectron spectroscopy using monochromatic Cr Kα radiation (5414.8 eV) has been used to acquire XPS and Auger data on a sputtered W sample. Survey data, high-resolution scans of all observed photoelectron peaks, and high-resolution scans of Auger lines are presented herein. [ABSTRACT FROM AUTHOR]

It remains a challenge to design aqueous electrolytes to secure the complete reversibility of zinc metal anodes. The concentrated water‐in‐salt electrolytes, e.g., 30 m ZnCl2, are promising candidates to address the challenges of the Zn metal anode. However, the pure 30 m ZnCl2 electrolyte fails to deliver a smooth surface morphology and a practically relevant Coulombic efficiency. Herein, it is reported that a small concentration of vanillin, 5 mg mLwater−1, added to 30 m ZnCl2 transforms the reversibility of Zn metal anode by eliminating dendrites, lowering the Hammett acidity, and forming an effective solid electrolyte interphase. The presence of vanillin in the electrolyte enables the Zn metal anode to exhibit a high Coulombic efficiency of 99.34% at a low current density of 0.2 mA cm−2, at which the impacts of the hydrogen evolution reaction are allowed to play out. Using this new electrolyte, a full cell Zn metal battery with an anode/cathode capacity (N/P) ratio of 2:1 demonstrates no capacity fading over 800 cycles. [ABSTRACT FROM AUTHOR]

Monochromatic Cr Kα radiation (5414.8 eV) has been used to acquire XPS and Auger data on a sputtered Pd sample. Survey data, high-resolution scans of all observed photoelectron peaks, and high-resolution scans of Auger lines are presented herein. [ABSTRACT FROM AUTHOR]

Ultrahigh vacuum delamination of buried metal/organic interfaces has yielded unperturbed X-ray photoemission spectra and has enabled quantitative analysis of the titanium/organic monolayer interface chemistry. The studies have shown that the formation of titanium oxide is strongly dependent on the deposition rate and chamber pressure.

The article titled "Cover Feature: The Role of Alkalis in Orchestrating Uranyl-Peroxide Reactivity Leading to Direct Air Capture of Carbon Dioxide" explores the use of depleted uranium in the form of uranyl triperoxide for carbon dioxide direct air capture (DAC) when combined with heavy alkali counter-cations. The researchers isolated highly reactive Cs+ and Rb+ uranyl triperoxide materials and found that the reactivity of the alkali uranyl triperoxide analogues increases with increasing alkali size. The study demonstrates the potential of alkali uranyl triperoxide materials for CO2 DAC in both solution and solid state. [Extracted from the article]

We report reversible electrochemical insertion of NO3− into manganese(II, III) oxide (Mn3O4) as a cathode for aqueous dual‐ion batteries. Characterization by TGA, FTIR, EDX, XANES, EXAFS, and EQCM collectively provides unequivocal evidence that reversible oxidative NO3− insertion takes place inside Mn3O4. Ex situ HRTEM and corresponding EDX mapping results suggest that NO3− insertion de‐crystallizes the structure of Mn3O4. Kinetic studies reveal fast migration of NO3− in the Mn3O4 structure. This finding may open a new direction for novel low‐cost aqueous dual‐ion batteries. The dual in the crown: Electrochemical quartz crystal microbalance measurement reveals the reversible insertion of nitrate into Mn3O4 which can be used as a cathode in aqueous dual‐ion batteries. Its capacity is one of the highest for anion‐storage cathode materials, higher than graphite and comparable to p‐type polymers. [ABSTRACT FROM AUTHOR]

In the article "Vanillin: An Effective Additive to Improve the Longevity of Zn Metal Anode in a 30 m ZnCl2 Electrolyte," researchers P. Alex Greaney, Xiulei Ji, and their colleagues discuss the challenges of designing aqueous electrolytes for zinc metal anodes in batteries. They found that adding a small amount of vanillin to a 30 m ZnCl2 electrolyte improves the reversibility of the anode, prevents dendrite formation, and increases Coulombic efficiency. This electrolyte formulation allows for stable cycling of a zinc metal battery with an N/P ratio of 2 for over 800 cycles. [Extracted from the article]