Generation of novel n-p-n (CeO-PPy-ZnO) heterojunction for photocatalytic degradation of micro-organic pollutants.

Recently, hetero junction materials (p-n-p and n-p-n) have been developed for uplifting the visible light activity to destroy the harmful pollutants in wastewater. This manuscript presents a vivid description of novel n-p-n junction materials namely CeO-PPy-ZnO. This novel n-p-n junction was applied as the photocatalyst in drifting the mobility of charge carriers and hence obtaining the better photocatalytic activity when compared with p-n and pure system.

Thermal evolution of NASICON type solid-state electrolytes with lithium at high temperature scanning electron microscopy.

We present the thermal evolution of two NASICON-type ceramics namely LATP (LiAlTi(PO)) and LAGP (LiAlGe(PO)) by monitoring the electrode-electrolyte interfaces (, Li/LATP and Li/LAGP) at temperatures up to 330 °C scanning electron microscopy, post-mortem energy-dispersive spectroscopy, and X-ray diffraction. Upon melting of Li and contacting electrolytes, LAGP decomposes completely to form Li based alloys, while LATP is partially decomposed without alloying.

On high-temperature evolution of passivation layer in Li-10 wt % Mg alloy via in situ SEM-EBSD.

Li-10 wt % Mg alloy (Li-10 Mg) is used as an anode material for a solid-state battery with excellent electrochemical performance and no evidence of dendrite formation during cycling. Thermal treatment of Li metal during manufacturing improves the interfacial contact between a Li metal electrode and solid electrolyte to achieve an all solid-state battery with increased performance. To understand the properties of the alloy passivation layer, this paper presents the first direct observation of its evolution at elevated temperatures (up to 325°C) by in situ scanning electron microscopy.

Synthesis and Performance of MOF-Based Non-Noble Metal Catalysts for the Oxygen Reduction Reaction in Proton-Exchange Membrane Fuel Cells: A Review.

Hydrogen is widely regarded as a prime energy carrier for bridging the gap between renewable energy supply and demand. As the energy-generating component of the hydrogen cycle, affordable and reliable fuel cells are of key importance to the growth of the hydrogen economy. However, the use of scarce and costly Pt as an electrocatalyst for the oxygen reduction reaction (ORR) remains an issue to be addressed, and in this regard, metal-organic frameworks (MOFs) are viewed as promising non-noble alternatives because of their self-assembly capability and tunable properties.

Phase Transformation of Doped LiCoPO during Galvanostatic Cycling.

In situ X-ray diffraction was employed to investigate the crystal structure changes in Cr/Si co-doped Li(Co,Fe)PO cathode material during a galvanostatic charge/discharge process at a slow rate of C/30. The evolution of the X-ray patterns revealed that the phase transformation between the Cr/Si-Li(Co,Fe)PO and Cr/Si-(Co,Fe)PO is a two-step process, which involves the formation of an intermediate compound of Cr/Si-Li(Co,Fe)PO upon the extraction of Li ions from the pristine phase. Different from the previously reported two biphasic transition steps, the phase transformation of the Cr/Si-Li(Co,Fe)PO followed a solid solution and a biphasic reaction pathway at different stages of the delithiation/lithiation process, respectively.

Application of Magnetic Resonance Techniques to the In Situ Characterization of Li-Ion Batteries: A Review.

In situ magnetic resonance (MR) techniques, such as nuclear MR and MR imaging, have recently gained significant attention in the battery community because of their ability to provide real-time quantitative information regarding material chemistry, ion distribution, mass transport, and microstructure formation inside an operating electrochemical cell. MR techniques are non-invasive and non-destructive, and they can be applied to both liquid and solid (crystalline, disordered, or amorphous) samples. Additionally, MR equipment is available at most universities and research and development centers, making MR techniques easily accessible for scientists worldwide.

Protection of LiFePO against Moisture.

In this study, a carbon-coated LiFePO (LFP/C) powder was chemically grafted with trifluoromethylphenyl groups in order to increase its hydrophobicity and to protect it from moisture. The modification was carried out by the spontaneous reduction of in situ generated 4-trifluoromethylphenyl ions produced by the diazotization of 4-trifluoromethylaniline. X-ray photoelectron spectroscopy was used to analyze the surface organic species of the modified powder.

Behavior of Solid Electrolyte in Li-Polymer Battery with NMC Cathode via in-Situ Scanning Electron Microscopy.

We present the first results of in situ scanning electron microscopy (SEM) of an all-solid Li battery with a nickel-manganese-cobalt-oxide (NMC-622) cathode at 50 °C and an operating voltage of 2.7-4.3 V.

Computational study of H binding to MH (M = Ti, V, or Cr).

A series of amorphous materials based on hitherto elusive early transition metal hydrides MH3 (M = Ti, V, and Cr) and capable of binding H2via the Kubas interaction has shown great promise for hydrogen storage applications, approaching US DoE system targets in some cases [Phys. Chem. Chem.

High Capacity and High Efficiency Maple Tree-Biomass-Derived Hard Carbon as an Anode Material for Sodium-Ion Batteries.

Sodium-ion batteries (SIBs) are in the spotlight because of their potential use in large-scale energy storage devices due to the abundance and low cost of sodium-based materials. There are many SIB cathode materials under investigation but only a few candidate materials such as carbon, oxides and alloys were proposed as anodes. Among these anode materials, hard carbon shows promising performances with low operating potential and relatively high specific capacity.

A photochemical diode artificial photosynthesis system for unassisted high efficiency overall pure water splitting.

The conversion of solar energy into chemical fuels can potentially address many of the energy and environment related challenges we face today. In this study, we have demonstrated a photochemical diode artificial photosynthesis system that can enable efficient, unassisted overall pure water splitting without using any sacrificial reagent. By precisely controlling charge carrier flow at the nanoscale, the wafer-level photochemical diode arrays exhibited solar-to-hydrogen efficiency ~3.

Atomic-Scale Origin of Long-Term Stability and High Performance of p-GaN Nanowire Arrays for Photocatalytic Overall Pure Water Splitting.

The atomic-scale origin of the unusually high performance and long-term stability of wurtzite p-GaN oriented nanowire arrays is revealed. Nitrogen termination of both the polar (0001¯) top face and the nonpolar (101¯0) side faces of the nanowires is essential for long-term stability and high efficiency. Such a distinct atomic configuration ensures not only stability against (photo) oxidation in air and in water/electrolyte but, as importantly, also provides the necessary overall reverse crystal polarization needed for efficient hole extraction in p-GaN.

High-Pressure Raman and Calorimetry Studies of Vanadium(III) Alkyl Hydrides for Kubas-Type Hydrogen Storage.

Reversible hydrogen storage under ambient conditions has been identified as a major bottleneck in enabling a future hydrogen economy. Herein, we report an amorphous vanadium(III) alkyl hydride gel that binds hydrogen through the Kubas interaction. The material possesses a gravimetric adsorption capacity of 5.

Thermodynamically neutral Kubas-type hydrogen storage using amorphous Cr(III) alkyl hydride gels.

In this paper we present amorphous chromium(III) hydride gels that show promise as reversible room temperature hydrogen storage materials with potential for exploitation in mobile applications. The material uses hydride ligands as a light weight structural feature to link chromium(III) metal centres together which act as binding sites for further dihydrogen molecules via the Kubas interaction, the mode of hydrogen binding confirmed by high pressure Raman spectroscopy. The best material possesses a reversible gravimetric storage of 5.

Proton conductivity of naphthalene sulfonate formaldehyde resin-doped mesoporous niobium and tantalum oxide composites.

Proton conductivity in a series of mesoporous niobium and tantalum metal oxide (mX2 O5 ) composites of naphthalene sulfonic acid formaldehyde resin (NSF) that are resistant to moisture loss at temperatures greater than 50 °C is reported. The investigation focuses on the effect to proton conductivity by changing pore size and metal in the mesostructure of the mX2 O5 system and thus, a series of mX2 O5 -NSF composites were synthesized with C6 , C12 , and C18 templates. These were characterized by XRD, thermogravimetric analysis, nitrogen adsorption, and scanning TEM and then studied using impedance spectroscopy to establish proton conductivity values at various temperatures ranging from 25 to 150 °C.

Hollow melon-seed-shaped lithium iron phosphate micro- and sub-micrometer plates for lithium-ion batteries.

Melon-seed-shaped LiFePO4 hollow micro- and sub-micrometer plates have been synthesized via a polyol-assisted hydrothermal method. The as-prepared LiFePO4 hollow materials were new with regard to their single-crystalline shells with large ac surfaces. Based on the detailed analysis of time-dependent studies, a possible growth mechanism was proposed involving nucleation, anisotropic growth, selective etching, and reversed recrystallization.

One-step overall water splitting under visible light using multiband InGaN/GaN nanowire heterostructures.

The conversion of solar energy into hydrogen via water splitting process is one of the key sustainable technologies for future clean, storable, and renewable source of energy. Therefore, development of visible light-responsive and efficient photocatalyst material has been of immense interest, but with limited success. Here, we show that overall water splitting under visible-light irradiation can be achieved using a single photocatalyst material.

Hydride-induced amplification of performance and binding enthalpies in chromium hydrazide gels for Kubas-type hydrogen storage.

Hydrogen is the ideal fuel because it contains the most energy per gram of any chemical substance and forms water as the only byproduct of consumption. However, storage still remains a formidable challenge because of the thermodynamic and kinetic issues encountered when binding hydrogen to a carrier. In this study, we demonstrate how the principal binding sites in a new class of hydrogen storage materials based on the Kubas interaction can be tuned by variation of the coordination sphere about the metal to dramatically increase the binding enthalpies and performance, while also avoiding the shortcomings of hydrides and physisorpion materials, which have dominated most research to date.