Monitoring Interfacial Dynamics of a Zinc-Ion Battery Cathode Using In Situ Grazing Incidence X-Ray Absorption Spectroscopy: A Case Study of Manganese Dioxide.

Despite such assets as intrinsic safety and low cost, the performance of zinc-ion batteries (ZIBs) is hindered by interfacial processes that occur at the cathode. Because of capacity fading and poor rate capability, manganese dioxide (MnO) cathodes are also negatively affected. Here, the novel application of in situ grazing incidence x-ray absorption spectroscopy (GI-XAS) to investigate the cathode-electrolyte interfacial dynamics in a MnO cathode ZIB is demonstrated.

Investigating Thermoelectric Properties of GeTe Alloys with Multi Element Doping: Insights from High-Entropy Engineering.

High-entropy engineering provides an effective strategy to enhance thermoelectric properties through increased lattice disorder induced by multielement doping. Recent multielement doping of GeTe-based alloys have significantly improved their thermoelectric performance, yet the vast compositional space of high-entropy GeTe makes identifying optimal compositions challenging. In this work, we investigate high-entropy GeTe alloys derived from the state-of-the-art GeAgSbPbBiTe system by partially adding Au to increase elemental and structural complexity without significantly degrading the electrical properties.

Nanosecond Laser Synthesis of MXene-Derived TiO/High-Entropy Alloys for Photo-Assisted Zinc-Air Batteries.

Photo-assisted zinc-air batteries have garnered significant attention for applying solar energy to decrease the charge voltage and improve energy efficiency. However, the uniform and rapid synthesis of highly active, stable, and low-cost photoelectrocatalysts for zinc-air batteries remains a significant challenge. Herein, a pulsed laser method is reported for the rapid preparation of MXene-derived TiO/high-entropy alloy heterojunctions (M-TiO/HEAs) as photoelectrocatalysts.

Lattice Water Deprotonation Enables Potassium-Ion Chemistries.

Electrochemical water splitting is a key process in clean energy applications and usually occurs on the surface of catalytic materials. Here, we report the anomalous partial water splitting, namely, water deprotonation behavior within the lattice of hydrated materials modeled by Fe Mg(CO) • 2HO (x ≈ 0.25-0.

Reversible Alkaline Sulfur Cathode Based on Six-Electron Electrochemistry for Advanced Aqueous Sulfur Batteries.

Aqueous sulfur batteries are promising for high-performance and low-cost energy storage. However, their energy density is limited by low battery voltages due to the negative potential [ = -0.51 V vs standard hydrogen electrode (SHE)] of low valent sulfur redox (S/S) and low discharge capacity (∼300 mA h g) of high valent sulfur redox (SO/SO or S/S).

Uncovering the Nonmonotonic Relationship between Total Activity and Single-Atom Density for Oxygen Reduction Catalysis.

In common sense, the total activity of single-atom catalysts (SACs) increases monotonically with the densification of single-atom sites, encouraging a general effort in developing high-density SACs for a variety of reactions, such as the oxygen reduction reaction (ORR). However, the intrinsic activity of each single-atom site may not remain constant with increasing density, since their growing interactions at the subnanometer scale can no longer be ignored. Here we report the nonmonotonic relationship between ORR activity and single-atom density, as revealed by theoretical calculations and experimental validation.

Reversible Anion-Cation Relay-Intercalation in a T-MnO Cathode to Boost the Efficiency of Aqueous Dual-Ion Batteries.

Benefiting from the merits of intrinsic safety, high power density, environmental friendliness, and high-output voltage, aqueous dual-ion batteries (ADIBs) have shown broad potential applications in future grid-scale energy storage. However, since the ADIBs require the cathodes to undergo the intercalation reactions through different local structures and mechanisms, causing large structural deformation and cathode failure, their reversible cation-anion intercalation in the cathode remains a major challenge. To address this issue, based on a reasonable selection and theoretical simulation, this work finds that Todorokite manganese dioxide (t-MnO) cathode with a metal-ion stabilized 3 × 3 large-tunnel structure should be suitable for cation-anion intercalation of ADIBs.

The role of sodium in the electrochemical tuning of LiTiSiO anodes across ceramic and glass phases.

This study investigates the enhancement of LiTiSiO anode material through Na doping via two routes: melt-quenching (route I) and subsequent heat treatment (route II). A 5 % Na-doped ceramic sample significantly improves Li-ion mobility and discharge capacity (215 mA h g at 10 mA g), sustaining 45 mA h g at a high rate of 1 A g. However, higher doping levels hinder performance, indicating Li-ion path obstruction and non-conductive impurities.

Exploring the Electrochemical Superiority of VO/TiO@TiC-MXene Hybrid Nanostructures for Enhanced Lithium-Ion Battery Performance.

The use of vanadium(V)-based materials as electrode materials in electrochemical energy storage (EES) devices is promising due to their structural and chemical variety, abundance, and low cost. V-based materials with a layered structure and high multielectron transfer in the redox reaction have been actively explored for energy storage. Our current work presents the structural and electrochemical properties of a vanadium-based composite with TiO@TiC MXene, referred to as VM.

Rational Design of Isolated Tetrahedrally Coordinated Ti(IV) Sites in Zeolite Frameworks for Methyl Oleate Epoxidation.

The rational design of isolated metals containing zeolites is crucial for the catalytic conversion of biomass-derived compounds. Herein, we explored the insertion behavior of the isomorphic substitution of Ti(IV) in different zeolite frameworks, including ZSM-35 (FER), ZSM-5, and BEA. The different aluminium topological densities of each zeolite framework lead to the creation of different degrees of vacant sites for hosting the tetrahedrally coordinated Ti(IV) active sites.

Rational Design of Fe Single Sites Supported on Hierarchical Zeolites Atomic Layer Deposition for Few-Walled Carbon Nanotube Production.

Metal single-site catalysts have recently played an essential role in catalysis due to their enhanced activity, selectivity, and precise reaction control compared to those of conventional metal cluster catalysts. However, the rational design and catalytic application of metal single-site catalysts are still in the early stages of development. In this contribution, we report the rational design of Fe single sites incorporated in a hierarchical ZSM-5 atomic layer deposition (ALD).

Correlation between biomedical and structural properties of Zn/Sr modified calcium phosphates.

This study investigates the correlation between the biomedical and structural properties of Zn/Sr-modified Calcium Phosphates (ZnSr-CaPs) synthesized via the sol-gel combustion method. X-ray diffraction (XRD) analysis revealed the presence of Ca(PO)(OH) (HAp), CaCO, and Ca(OH) phases in the undoped sample, while the additional phase, Ca(PO) (β-TCP) was formed in modified samples. X-ray absorption near-edge structure (XANES) analysis demonstrated the incorporation of Sr into the lattice, with a preference for occupying the Ca1 sites in the HAp matrix.

Unraveling the Electrocatalytic Activity in HMF Oxidation to FDCA by Fine-Tuning the Degree of NiOOH Phase Over Ni Nanoparticles Supported on Graphene Oxide.

The development of an efficient electrocatalyst for HMF oxidation to FDCA has been in the early stages. Herein, the NiNPs/GO-Ni-foam is fabricated as an electrocatalyst for FDCA production. However, the electrocatalytic performance of the untreated NiNPs/GO-Ni-foam is observed with moderate Faradaic efficiency (FE) (73.

Unraveling Structural and Acidic Properties of Al-SBA-15-supported Metal Phosphates: Assessment for Glucose Dehydration.

5-Hydroxymethylfurfural (5-HMF) synthesized through glucose conversion requires Lewis acid (L) site for isomerization and Brønsted acid (B) site for dehydration. The objective of this work is to investigate the influence of the metal type of Al-SBA-15-supported phosphates of Cr, Zr, Nb, Sr, and Sn on glucose conversion to 5-HMF in a NaCl-H O/n-butanol biphasic solvent system. The structural and acid property of all supported metal phosphate samples were fully verified by several spectroscopic methods.

Interfacial Reconstruction for Regulating Zn Deposition toward Ultrastable Zn Metal Anodes.

Rechargeable aqueous zinc-ion batteries (AZIBs) are attracting much attention as high-density energy storage systems owing to their fascinating features with low cost, high safety, and simple manufacturing process. However, the commercialization of Zn anodes is hindered by uncontrollable dendrite growth and water-induced side reactions. Herein, a spontaneous reconstruction of a honeycomb-structural hopeite layer (ZPO) on a Zn metal anode (Zn@ZPO) is rationally developed as a functional protection interface by the liquid-phase deposition strategy.

Stable Immobilization of Nickel Ions on Covalent Organic Frameworks for Panchromatic Photocatalytic Hydrogen Evolution.

Post-coordination design on covalent organic frameworks (COFs) is an efficient strategy for elevating the photocatalytic activity of organic moiety. However, the rigid skeletons and densely layered stacking of two-dimensional (2D) COFs cannot be flexibly adapted for specific conformations of metal complexes, thereby impairing the metal-COF cooperation. Here, we adopt a solvothermal method to immobilize nickel(II) ions into a 2,2'-bipyridine-containing 2D COF, forming a stable coordination motif.

Coordination Chemistry of Large-Sized Yttrium Single-Atom Catalysts for Oxygen Reduction Reaction.

Although being transition metals, the Fenton-inactive group 3-4 elements (Sc, Y, La, Ti, Zr, and Hf) can easily lose all the outermost s and d electrons, leaving behind ionic sites with nearly empty outermost orbitals that are stable but inactive for oxygen involved catalysis. Here, it is demonstrated that the dynamic coordination network can turn these commonly inactive ionic sites into platinum-like catalytic centers for the oxygen reduction reaction (ORR). Using density functional theory calculations, a macrocyclic ligand coordinated yttrium single-atom (YN ) moiety is identified, which is originally ORR inactive because of the too strong binding of hydroxyl intermediate, while it can be activated by an axial ligand X through the covalency competition between YX and YOH bonds.

Enhancement of VO Li-ion cathode stability by Ni/Co doped Li-borate-based glass.

In this research, we investigate the stability of a Li-ion cathode created by mixing a borate based glass which has been doped with Ni/Co and vanadium pentoxide (VO). VO has a high specific capacity in battery systems because of its layered structure and variety of oxidation states. However, due to the flimsy structure, the capacity stability of VO is fairly low.

Structural elucidation of hexavalent Cr adsorbed on surfaces and bulks of FeO and α-FeOOH.

Magnetite (FeO) and goethite (α-FeOOH) were synthesized a hydrothermal approach and utilized as adsorbents for Cr removal in an aqueous medium. The typical crystal structures of the synthesized FeO and α-FeOOH were confirmed by XRD and TEM. FeO in a spherical shape with a surface area of 32 m g was established.

Correlating the effect of preparation methods on the structural and magnetic properties, and reducibility of CuFeO catalysts.

CuFeO spinel oxide has attracted research interest because of its versatile practical applications, especially for catalysis. In this study, nanometre-sized CuFeO particles were prepared by three different methods, including nanospace confinement in SBA-15, hard template removal, and sol-gel combustion. The relationship between structure, size, magnetic behaviour, and reducibility of the catalysts was further investigated by various advanced techniques.

Metalloid-Cluster Ligands Enabling Stable and Active FeN -Te Motifs for the Oxygen Reduction Reaction.

In nature, the oxygen reduction reaction (ORR) is catalyzed by cytochrome P450 (CYP) enzymes containing heme iron centers with an axial thiolate ligand (FeN -S), which are among the most finely developed catalysts by natural selection. However, the exceptional ORR activity and selectivity of CYP enzymes originate from their non-rigid and self-adaptive coordination network with molecular ligands, which sacrifices the stability of the active motifs under electrochemical reaction conditions. Here, a design strategy to circumvent this dilemma by incorporating Fe-N motifs into carbon matrices instead of the protein scaffold and replacing the axial molecular thiolate ligand with a stable tellurium cluster (Te ) is demonstrated.

An Operando X-ray Absorption Spectroscopy Study on Sensing Characteristics of Vertically Aligned ZnO Thin Film for Methane Gas Sensors.

In this work, a simple, facile growth approach for a vertically aligned ZnO thin film is fabricated and its application towards methane gas sensors is demonstrated. ZnO thin film was prepared by a combination of hydrothermal and sputtering methods. First, a ZnO seed layer was prepared on the substrate through a sputtering technique, then a ZnO nanorod was fabricated using a hydrothermal method.

Modulation of Single Atomic Co and Fe Sites on Hollow Carbon Nanospheres as Oxygen Electrodes for Rechargeable Zn-Air Batteries.

Efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are required for metal air batteries, to replace costly metals, such as Pt and Ir/Ru based compounds, which are typically used as benchmarks for ORR and OER, respectively. Isolated single atomic sites coordinated with nitrogen on carbon supports (M-N-C) have promising performance for replacement of precious metal catalysts. However, most of monometallic M-N-C catalysts demonstrate unsatisfactory bifunctional performance.

Proton/Electron Donors Enhancing Electrocatalytic Activity of Supported Conjugated Microporous Polymers for CO Reduction.

Metal phthalocyanines (MePc) hold great promise in electrochemical reduction of CO to value-added chemicals, whereas the catalytic activity of MePc-containing polymers often suffers from a limited molecular modulation strategy. Herein, we synthesize an ultrathin conjugated microporous polymer sheath around carbon nanotubes by an ionothermal copolymerization of CoPc and H Pc via the Scholl reaction. Given the H Pc-mediated regulation in the synthesis, Co metal is well preserved in the form of single atoms on the polymer sheath of the carbon nanotubes.

Roles of Mo dopant in BiWO for enhancing photocatalytic activities.

We present the investigation of the roles of molybdenum (Mo) dopant with a concentration of 0.0625% to 1.0% Mo into bismuth tungstate (BiWO) by a one-step hydrothermal method for the enhancement of photocatalytic activities.