Codecoration of Phosphate and Iron for Improving Oxygen Evolution Reaction of Layered Ni(OH)₂/NiOOH

Hydrogen production through electrochemical water splitting (EWS) presents a viable solution for addressing the fossil energy crisis. However, the commercial viability of this approach is impeded by the sluggish kinetics of the oxygen evolution reaction (OER). It is urgently needed to develop efficient, stable, and cost-effective OER electrocatalysts. Herein, we comprehensively design and investigate a phosphate ion and Fe3+ codecorating Ni(OH)2/NiOOH electrocatalyst (Pi-Fe:NiOH) for OER. This codecoration induces multiple synergistic effects, which include an increase in the interlayer water content for the internal OER, altering the OER mechanism, facilitating proton transport across the layers, and improving the stability of Pi-Fe:NiOH. Consequently, Pi-Fe:NiOH exhibits a high OER activity with overpotentials of 118 ± 1 and 222 ± 4 mV at current densities of 10 and 100 mA cm–2, respectively. More impressively, it maintains stable operation at a high current density of around 300 mA cm–2 for at least 500 h, much better than the Ni(OH)2/NiOOH electrocatalyst (NiOH) for less than 6 h at a current density below 200 mA cm–2. These findings offer insights for the design of anion–cation codoped hydroxide eletrocatalysts, paving a way for the development of efficient and stable OER electrocatalysts

Characterization of Modified Phenol Formaldehyde Resole Resins Synthesized in Situ with Various Boron Compounds

In this study, three different boron compounds were used together with alkaline catalyst to synthesize phenol formaldehyde (PF) resole resins in situ. The resin curing behavior, molecular structure, bonding performance, and properties of resin-impregnated wood were investigated. Results showed that boron compound-modified PF resins had a lower degree of polymerization than the control PF resin made in the laboratory. The curing kinetics, molecular structure, and functional groups of the modified resins varied depending on the type of boron compounds used. The thermal stability of cured modified PF resins was slightly lower than that of laboratory-made control PF resin. Boron compound-modified PF resins exhibited dry and wet bonding strengths comparable to the those of the laboratory-made control PF resin. Wood impregnated using modified PF resins had comparable dimensional stability, mechanical properties and improved fire resistance than the wood impregnated using lab made control PF resin regardless the type of boron compounds used

Insight into the Growth of Non-uniform Vanadium-Doped Molybdenum Disulfide for Tunable Electronic Properties

Element doping in two-dimensional (2D) materials can introduce novel physical–chemical properties, and the obtained crystals are widely used as platforms for investigating unique properties and as functional units for advanced applications. However, the uniformity of doping, as an important step to define the doping properties, is not yet fully understood. In this study, vanadium (V)-doped molybdenum disulfide (MoS2) is used as an example to study the correlation between non-uniform doping and electronic properties. A thermodynamically stable doping structure was initially predicted theoretically and subsequently reached by a robust chemical vapor deposition method. The V atoms were dispersed non-uniformly throughout the MoS2 lattice, leading to a doping concentration gradient in the V-doped MoS2 conductive channel for corresponding field effect transistors. This work focused on the uniformity characteristics of element-doped 2D materials, an important but often ignored topic, and it will potentially help improve the reliability of 2D materials’ applications

Organophosphonate-Bridged Polyoxometalate-Based Dysprosium(III) Single-Molecule Magnet

A novel dysprosium­(III)-containing polytungstoarsenate, [{(AsW₉O₃₃)₃Dy₂(H₂O)₄W₄O₉(H₂O)}₂(NH₂(CH₂PO₃)₂)]^33–, comprising two identical subunits bridged by an organophosphonate ligand shows single-molecule-magnet (SMM) behavior. Magnetic studies reveal that this complex exhibits a butterfly-shaped hysteresis loop up to 8 K, and a thermally activated energy barrier of 101(5) K reached a breakthrough among all polyoxometalate-supported SMMs

Understanding the copassivation effect of Cl and Se for CdTe grain boundaries

Chlorine passivation treatment of cadmium telluride (CdTe) solar cells improves device performance by assisting electron−hole carrier separation at CdTe grain boundaries. Further improvement in device efficiency is observed after alloying the CdTe absorber layer with selenium. High-resolution secondary ion mass spectroscopy (NanoSIMS) imaging has been used to determine the distribution of selenium and chlorine at the CdTe grain boundaries in a selenium-graded CdTe device. Atomistic modeling based on density functional theory (DFT-1/2) further reveals that the presence of selenium and chlorine at an exemplar (110)/(100) CdTe grain boundary passivates critical acceptor defects and leads to n-type inversion at the grain boundary. The defect state analysis provides an explanation for the band-bending effects observed in the energy band alignment results, thereby elucidating mechanisms for high efficiencies observed in Se-alloyed and Cl-passivated CdTe solar cells