Unravelling the Enigma of Nonoxidative Conversion of Methane on Iron Single-Atom Catalysts

The direct, nonoxidative conversion of methane on a silica-confined single-atom iron catalyst is a landmark discovery in catalysis, but the proposed gas-phase reaction mechanism is still open to discussion. Here, we report a surface reaction mechanism by computational modeling and simulations. The activation of methane occurs at the single iron site, whereas the dissociated methyl disfavors desorption into gas phase under the reactive conditions. In contrast, the dissociated methyl prefers transferring to adjacent carbon sites of the active center (Fe₁©SiC₂), followed by C−C coupling and hydrogen transfer to produce the main product (ethylene) via a key −CH−CH₂ intermediate. We find a quasi Mars–van Krevelen (quasi-MvK) surface reaction mechanism involving extracting and refilling the surface carbon atoms for the nonoxidative conversion of methane on Fe₁©SiO₂ and this surface process is identified to be more plausible than the alternative gas-phase reaction mechanism.     

Adaptive Bifunctional Electrocatalyst of Amorphous CoFe Oxide @ 2D Black Phosphorus for Overall Water Splitting

Water electrolysis offers a promising green technology to tackle the global energy and environmental crisis, but its efficiency is greatly limited by the sluggish reaction kinetics of both the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). In this work, by growing amorphous multi-transition-metal (cobalt and iron) oxide on two-dimensional (2D) black phosphorus (BP), we develop a bifunctional electrocatalyst (CoFeO@BP), which is able to efficiently catalyze both HER and OER. The overpotentials for the hybrid CoFeO@BP catalyst to reach a current density of 10 mA cm⁻² in 1 m KOH are 88 and 266 mV for HER and OER, respectively. Based on a series of ex-situ and in situ investigations, the excellent catalytic performance of CoFeO@BP is found to result from the adaptive surface structure under reduction and oxidation potentials. CoFeO@BP can be transformed to CoFe phosphide under reduction potential, in situ generating the real active catalyst for HER.     

A Robust Mixed-Lanthanide PolyMOF Membrane for Ratiometric Temperature Sensing

Temperature sensors play a significant role in biology, chemistry, and engineering, especially those that can work accurately in a noninvasive manner. We adopted a photoinduced post-synthetic copolymerization strategy to realize a membranous ratiometric luminescent thermometer based on the emissions of two lanthanide ions. This novel mixed-lanthanide polyMOF membrane exhibits not only the integrity and temperature sensing behaviour of the Ln-MOF powder but also excellent mechanical properties, such as flexibility, elasticity, and processability. Moreover, the polyMOF membrane shows remarkable stability under harsh conditions, including high humidity, strong acid and alkali (pH 0–14), which allowed the mapping of temperature distributions in extreme circumstances. This work highlights a simple strategy for polyMOF membrane formation and pushes forward the further practical application of Ln-MOF-based luminescent thermometers in various fields and conditions.     

Kinetics and isothermal adsorption of U(VI) in aqueous solution by nano-Ni0

Journal of Radioanalytical and Nuclear Chemistry - The nanoscale zero-valent nickel (nano-Ni0) was prepared by liquid-phase reduction method and characterized by BET, XPS, FT-IR and XRD and be used...     

Bubble dynamics and heat transfer characteristics on a micropillar-structured surface with different nucleation site positions

Journal of Thermal Analysis and Calorimetry - Microstructured surfaces have been extensively employed to enhance nucleate boiling. However, enhancement mechanisms have not been fully understood. In...     

Development and application of electrochemical sensor of boron-doped diamond (BDD) modified by drop casting with tin hexacyanoferrate

Journal of Solid State Electrochemistry - This work presents the development and characterization of an electrochemical sensor of tin hexacyanoferrate (SnHCF), produced from the modification by...