Enhanced catalytic activity of edge-exposed 1T phase WS 2 grown directly on a WO 3 nanohelical array for water splitting

Kim

et al. 2022

IJMS

Research on layered two-dimensional (2D) materials is at the forefront of material science. Because 2D materialshave variousplate shapes, there is a great deal of research on the layer-by-layer-type junction structure. In this study, we designed a composite catalyst with a dimension lower than two dimensions and with catalysts that canbe combined so that the band structures can be designed to suit various applications and cover for each other’s disadvantages. Among transition metal dichalcogenides, 1T-WS2 can be a promising catalytic material because of its unique electrical properties. Black phosphorus with properly controlled surface oxidation can act as a redox functional group. We synthesized black phosphorus that was properly surface oxidized by oxygen plasma treatment and made a catalyst for water quality improvement through composite with 1T-WS2. This photocatalytic activity was highly efficient such that the reaction rate constant k was 10.31×10−2 min−1. In addition, a high-concentration methylene blue solution (20 ppm) was rapidly decomposed after more than 10 cycles and showed photo stability. Designing and fabricating bandgap energy-matching nanocomposite photocatalysts could provide a fundamental direction in solving the future’s clean energy problem.

Section: Resultsmentioning

confidence: 99%

P=O Functionalized Black Phosphorus/1T-WS2 Nanocomposite High Efficiency Hybrid Photocatalyst for Air/Water Pollutant Degradation

Jeong

Kim

et al. 2022

IJMS

“…Subsequently, the deposited WO 3 sample was annealed on muffle furnace (Daeheung Science, model DF-3.5) at 500 °C for 2 h as reported in our previous study. 25,32 2.3. Sulfurization of the WO 3 NH.…”

Section: Methodsmentioning

confidence: 99%

“…The sulfurization was conducted at 550 °C for 15 min with preannealed WO 3 samples loaded on the center of quartz tube and sulfur powder placed at the upstream side. 25,32 2.4. Surface Characterization.…”

Section: Methodsmentioning

confidence: 99%

Three-Dimensional Tungsten Disulfide Raman Biosensor for Dopamine Detection

Shin

et al. 2020

ACS Appl. Bio Mater.

Self Cite

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising materials for detection of biomolecules due to their large surface-to-volume ratio. However, their poor response to the cellular environment hinders the realization of high-performance 2D TMDC sensors. Here, we present a hierarchical Raman scattering sensor consisting of the WS2 directly grown on an array of three-dimensional (3D) WO3 nanohelixes (NHs) by sulfurization. Both the adsorption of biomolecules and the proliferation of cells are significantly promoted for the 3D WS2/WO3 NH sensor compared to the control sensor with sulfurized WS2 on 2D WO3 film, leading to much enhanced sensitivity to dopamine. In addition, according to the in vitro test using PC12 cells, the 3D WS2/WO3 NH sensor shows a significant increase in hydrophobicity and Raman frequency shift, indicating that both the attachment of cells and the detection of biomolecules are improved.

Advanced Energy Materials

“…[20] We also theoretically and experimentally demonstrated that 2D MoSe 2 with only 3-5 layers can work as the grain promoter to induce direct Li 2 O 2 formation/decomposition in LOBs. [32] The stacked edge facets containing van der Waals forces in 2D materials have also been demonstrated to possess excellent catalytic activity for water splitting, [33] hydrogen generation, [34] and other energy storage applications. [35] Moreover, different stack units will create different 2D structures, such as octahedron layer-stacked transition metal dichalcogenides (TMDs) including 1T, 2H phase MoS 2 , MoSe 2 , M-C layerstacked MXene (Ti n C n−1 , Nb 2 C), tetrahedron layer stacked FeSe, and black phosphorus-like 2D structures composed of simple atomic layers.…”

Section: Introductionmentioning

confidence: 99%

2D SnSe Cathode Catalyst Featuring an Efficient Facet‐Dependent Selective Li₂O₂ Growth/Decomposition for Li–Oxygen Batteries

Zhang

Wang

et al. 2022

during charge. [5][6][7] Unfortunately, some technological hurdles limit the practical utilization of LOBs, including high overpotentials, poor cycling performance, low capacity much below the theoretical value, and low round-trip efficiency. [1] These critical issues are closely connected to the inferior electronic/ionic conductivity of the inactive discharge product Li 2 O 2 , which results in sluggish reaction kinetics, strong redox reaction intermediates, and side reactions between carbon and electrolyte/solid products. [4,[8][9][10][11] Highly efficient cathode materials for reversible formation/ decomposition (ORR/OER) of discharge products determine the electrochemical performance of LOBs to a great extent. [8,12] On the other hand, the reaction kinetics on the cathode catalyst are not only dominated by the Li 2 O 2 formation/decomposition process, but also the adsorption/ desorption of absorbates such as O 2 , Li + , and LiO 2 . [2,[13][14][15][16][17][18] A highly efficient cathode catalyst should possess both high active catalytic capability for the ORR/OER process and appropriate adsorption ability to ensure smooth reaction kinetics. [19,20] Materials with a 2D layered structure have received considerable attention for use in catalytic, electronic and optoelectronic devices [21][22][23][24] due to their unique properties including a large surface area, [25] flexible stack layers, [26] electron confinement effect, [27] high carrier mobility, and thickness-tunable bandgap modulation. [28] Recently, 2D materials were theoretically and 2D materials are attracting much attention in the field of cathode catalysts for lithium-oxygen batteries (LOBs) due to their layered structure, unique electronic properties, and high stability. However, different stacking layer structures trigger different catalytic capabilities in LOBs. In this work, tin selenide nanosheets with a black phosphorus-like 2D structure are synthesized and used as the cathode catalyst for LOBs. SnSe nanosheets with exposed stack (200) facets and stack edge facets exhibit superior specific capacity over 20 783 mAh g −1 and ultralong cycle stability over 380 cycles at 500 mA g −1 in LOBs. This demonstrates that the growth of discharge products is mainly concentrated on the 2D surface (200) facets, rather than the stack edge facets. Experimental and theoretical studies reveal that the confined adsorption of Li 2 O 2 on the stack edge facets of SnSe, due to the 2D layer structure and the unique electron distribution, restricts the growth of discharge products. The 2D surface facets of SnSe benefit for the formation and stabilization of LiO 2 intermediates, leading to the efficient formation/ decomposition of discharge products. The findings provide in-depth insight into the elusive electrocatalytic mechanism for 2D layer-structures materials in LOBs.