Using Collagen Fiber as a Template to Synthesize Hierarchical Mesoporous Alumina Fiber

Hierarchical mesoporous alumina fiber was synthesized by using collagen fiber as the template, and characterized by means of scanning electron microscopy, transmission electron microscopy, N2 adsorption techniques, X-ray photoelectron spectroscopy, and X-ray diffraction. The alumina fiber obtained is approximately 1−4 μm in outer diameter and 0.5−1 mm in length. The pore size distribution of the alumina fiber is narrow (2−20 nm), and its pore size is controllable by varying preparation methods. This study indicates that collagen fiber, which has hierarchical supermolecular structure, could be used as an ideal template to prepare well-defined porous metal oxide fibers

Surface-Preferred Crystal Plane Growth Enabled by Underpotential Deposited Monolayer toward Dendrite-Free Zinc Anode

Aqueous Zn batteries with ideal energy density and absolute safety are deemed the most promising candidates for next-generation energy storage systems. Nevertheless, stubborn dendrite formation and notorious parasitic reactions on the Zn metal anode have significantly compromised the Coulombic efficiency (CE) and cycling stability, severely impeding the Zn metal batteries from being deployed in the proposed applications. Herein, instead of random growth of Zn dendrites, a guided preferential growth of planar Zn layers is accomplished via atomic-scale matching of the surface lattice between the hexagonal close-packed (hcp) Zn(002) and face-centered cubic (fcc) Cu(100) crystal planes, as well as underpotential deposition (UPD)-enabled zincophilicity. The underlying mechanism of uniform Zn plating/stripping on the Cu(100) surface is demonstrated by ab initio molecular dynamics simulations and density functional theory calculations. The results show that each Zn atom layer is driven to grow along the exposed closest packed plane (002) in hcp Zn metal with a low lattice mismatch with Cu(100), leading to compact and planar Zn deposition. In situ optical visualization inspection is adopted to monitor the dynamic morphology evolution of such planar Zn layers. With this surface texture, the Zn anode exhibits exceptional reversibility with an ultrahigh Coulombic efficiency (CE) of 99.9%. The MnO2//Zn@Cu­(100) full battery delivers long cycling stability over 548 cycles and outstanding specific energy and power density (112.5 Wh kg–1 even at 9897.1 W kg–1). This work is expected to address the issues associated with Zn metal anodes and promote the development of high-energy rechargeable Zn metal batteries

Surface-Preferred Crystal Plane Growth Enabled by Underpotential Deposited Monolayer toward Dendrite-Free Zinc Anode

Aqueous Zn batteries with ideal energy density and absolute safety are deemed the most promising candidates for next-generation energy storage systems. Nevertheless, stubborn dendrite formation and notorious parasitic reactions on the Zn metal anode have significantly compromised the Coulombic efficiency (CE) and cycling stability, severely impeding the Zn metal batteries from being deployed in the proposed applications. Herein, instead of random growth of Zn dendrites, a guided preferential growth of planar Zn layers is accomplished via atomic-scale matching of the surface lattice between the hexagonal close-packed (hcp) Zn(002) and face-centered cubic (fcc) Cu(100) crystal planes, as well as underpotential deposition (UPD)-enabled zincophilicity. The underlying mechanism of uniform Zn plating/stripping on the Cu(100) surface is demonstrated by ab initio molecular dynamics simulations and density functional theory calculations. The results show that each Zn atom layer is driven to grow along the exposed closest packed plane (002) in hcp Zn metal with a low lattice mismatch with Cu(100), leading to compact and planar Zn deposition. In situ optical visualization inspection is adopted to monitor the dynamic morphology evolution of such planar Zn layers. With this surface texture, the Zn anode exhibits exceptional reversibility with an ultrahigh Coulombic efficiency (CE) of 99.9%. The MnO2//Zn@Cu­(100) full battery delivers long cycling stability over 548 cycles and outstanding specific energy and power density (112.5 Wh kg–1 even at 9897.1 W kg–1). This work is expected to address the issues associated with Zn metal anodes and promote the development of high-energy rechargeable Zn metal batteries

Surface-Preferred Crystal Plane Growth Enabled by Underpotential Deposited Monolayer toward Dendrite-Free Zinc Anode

Aqueous Zn batteries with ideal energy density and absolute safety are deemed the most promising candidates for next-generation energy storage systems. Nevertheless, stubborn dendrite formation and notorious parasitic reactions on the Zn metal anode have significantly compromised the Coulombic efficiency (CE) and cycling stability, severely impeding the Zn metal batteries from being deployed in the proposed applications. Herein, instead of random growth of Zn dendrites, a guided preferential growth of planar Zn layers is accomplished via atomic-scale matching of the surface lattice between the hexagonal close-packed (hcp) Zn(002) and face-centered cubic (fcc) Cu(100) crystal planes, as well as underpotential deposition (UPD)-enabled zincophilicity. The underlying mechanism of uniform Zn plating/stripping on the Cu(100) surface is demonstrated by ab initio molecular dynamics simulations and density functional theory calculations. The results show that each Zn atom layer is driven to grow along the exposed closest packed plane (002) in hcp Zn metal with a low lattice mismatch with Cu(100), leading to compact and planar Zn deposition. In situ optical visualization inspection is adopted to monitor the dynamic morphology evolution of such planar Zn layers. With this surface texture, the Zn anode exhibits exceptional reversibility with an ultrahigh Coulombic efficiency (CE) of 99.9%. The MnO2//Zn@Cu­(100) full battery delivers long cycling stability over 548 cycles and outstanding specific energy and power density (112.5 Wh kg–1 even at 9897.1 W kg–1). This work is expected to address the issues associated with Zn metal anodes and promote the development of high-energy rechargeable Zn metal batteries

High-Pressure Electro-Fenton Driving CH₄ Conversion by O₂ at Room Temperature

Electrochemical conversion of CH4 to easily transportable and value-added liquid fuels is highly attractive for energy-efficient CH4 utilization, but it is challenging due to the low reactivity and solubility of CH4 in the electrolyte. Herein, we report a high-pressure electro-Fenton (HPEF) strategy to establish a hetero-homogeneous process for the electrocatalytic conversion of CH4 by O2 at room temperature. In combination with elevation of reactant pressure to accelerate reaction kinetics, it delivers an unprecedented HCOOH productivity of 11.5 mmol h–1 gFe–1 with 220 times enhancement compared to that under ambient pressure. Remarkably, an HCOOH Faradic efficiency of 81.4% can be achieved with an ultralow cathodic overpotential of 0.38 V. The elevated pressure not only promotes the electrocatalytic reduction of O2 to H2O2 but also increases the reaction collision probability between CH4 and •OH, which is in situ generated from the Fe2+-facilitated decomposition of H2O2

Hydrogenation of Nitroarenes by Onsite-Generated Surface Hydroxyl from Water

Directly using water as a hydrogen source for hydrogenation of nitroarenes to anilines (HNA) without using H2 is an ideal reduction reaction route but is limited by unfavorable thermodynamics. Herein, we report a high-efficiency and durable H2O-based HNA process achieved by using in situ-generated hydroxyl species from water as a hydrogen donor and low-cost CO as an oxygen acceptor over a molybdenum carbide-supported gold catalyst (Au/α-MoC1–x). It affords nitroarene conversion of over 99% with aniline selectivity of over 99% and excellent functional group tolerance at 25 °C and remains stable after 10 cycles, outperforming the traditional H2-involved route. Spectroscopic and theoretical studies reveal the key role of Au/α-MoC1–x boundaries, at which not only hydroxyl species are generated as a soft reductant on α-MoC1–x but also the nitro group is selectively hydrogenated to anilines with other unsaturated groups intact, and residual O* is removed by adsorbed CO on the atomically thin Au layer. This process provides a durable H2O-based route for aniline production at room temperature

Efficiency scrutiny - have they listened? Third survey of Government policy towards the voluntary sector in Wales, 1993/94

SIGLEAvailable from British Library Document Supply Centre- DSC:7672.0114(WCVA-R--3) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Single-Atomic Ir and Mo Co-Confined in a Co Layered Hydroxide Nanobox Mutually Boost Oxygen Evolution

The sluggish four-electron-transfer kinetics of the oxygen evolution reaction (OER) is a great challenge for the development of efficient and cost-effective OER electrocatalysts. Herein, we report single-atomic Ir and Mo co-confined in the lattice of a Co layered hydroxide (Co-LH) nanobox as an efficient OER electrocatalyst via a sacrificial template method. With the hollow structure and synergetic electronic interactions among Ir, Mo, and Co-LH, the catalyst delivers an ultralow overpotential of 220 mV at 10 mA cm–2 and high durability of over 800 h at 50 mA cm–2 in 1 M KOH, which significantly outperform the commercial Ir black catalyst. Density functional theory calculations indicate that adjacent Mo and Ir enhance the OER activities on the Ir sites at defects (defect-Ir) and Mo sites in the plane (in-plane-Mo), respectively. This study provides not only a highly efficient OER catalyst but also a strategy for confining dual-active centers with mutually improved catalytic activities

Toward N-Doped Graphene via Solvothermal Synthesis

Theoretical studies predicted that doping graphene with nitrogen can tailor its electronic properties and chemical reactivity. However, experimental investigations are still limited because of the lack of synthesis techniques that can deliver a reasonable quantity. We develop here a novel method for one-pot direct synthesis of N-doped graphene via the reaction of tetrachloromethane with lithium nitride under mild conditions, which renders fabrication in gram scale. The distinct electronic structure perturbation induced by the incorporation of nitrogen in the graphene network is observed for the first time by scanning tunnelling microscopy. The nitrogen content varies in the range of 4.5−16.4%, which allows further modulation of the properties. The enhanced catalytic activity is demonstrated in a fuel cell cathode oxygen reduction reaction with respect to pure graphene and commercial carbon black XC-72. The resulting N-doped materials are expected to broaden the already widely explored potential applications for graphene