ABSTRACT
Developing the earth-abundant transition metal-based bifunctional electrocatalysts for water splitting and renewable energy devices has attracted much attention. Herein, we report a 1 T-WS2 in ultrathin nanosheet arrays grafted with Co4S3 on conductive carbon cloth (CC) (1 T-Co4S3-WS2/CC) through a feasible in-situ growth and vulcanization. The optimized 1 T-Co4S3-WS2/CC catalyst exhibits an impressive electrocatalytic activity and remarkable stability with the oxygen/hydrogen evolution reaction (OER/HER: 278/75 mV for 10 mA cm-2). It also showed the small Tafel slope values of 61.7 and 58.4 mV dec-1, respectively. Additionally, the 1 T-Co4S3-WS2/CC(-/+) achieved 1.59 V@10 mA cm-2 in alkaline media superior to the most previously reported non-precious metal electrocatalysts. The outstanding performance could be attributed to the synergy between heterostructures of Co4S3 and 1 T-WS2 modifying the electronic structure to accelerate water splitting kinetics. Thus, this work presents a rational design of scalable, high-efficiency, stable water splitting electrocatalysts based on WS2.
ABSTRACT
The porous Co3O4 nanowires were fabricated using a fluoride anion-assisted hydrothermal and controlled annealing route. The nanowires showed superior CO gas-sensing performances, such as high selectivity against CO and optimal sensing activity at a relatively low operating temperature (Top ≤ 100 °C). Such properties were ascribed to fluoride doping and porous nanowire structure.
Subject(s)
Carbon Monoxide/analysis , Chemistry Techniques, Analytical/instrumentation , Cobalt/chemistry , Nanowires/chemistry , Oxides/chemistry , Temperature , PorosityABSTRACT
Uniform hexagram-shaped alpha-Fe2O3 microcrystals with tunable morphologies were fabricated by a facile hydrothermal method followed by annealing in air. The highly anisotropic hexagram-shaped alpha-Fe2O3 particles with the higher coercivity forces and remannent magnetizations showed weak ferromagnetic behaviors at room temperature and displayed the typical shape-dependent magnetic behaviors.
ABSTRACT
X-shaped goethite iron oxide crystals were synthesized by a surfactant-free mild hydrothermal synthesis method with the aid of fluorine ions. The X-shaped goethite crystals could readily self-assemble into microscopic hollow spheres through an oil-water interface induced self-assembly method. X-shaped hematite crystals were obtained by phase topotactic transformation of the goethite precursors. The gas sensor properties of X-shaped hematite iron oxide were investigated, and the mechanism for excellent sensor properties was discussed.
ABSTRACT
Say it with flowers: Flower-like Fe(3)O(4)@Fe(OH)(3) composite catalysts show good activity and stability in the synthesis of cyclic carbonates from epoxides and CO(2). The role of hydrogen bonding between the surface hydroxyl groups of the solid and the epoxides at the solid/liquid interface is proposed as a key factor in activating the epoxide and stabilizing the ring-opened carbonate intermediates.