S-C3N4 Quantum Dot Decorated ZnO Nanorods to Improve Their Photoelectrochemical Performance

NANO ◽  
2017 ◽  
Vol 12 (05) ◽  
pp. 1750064 ◽  
Author(s):  
Haizhou He ◽  
Jie Li ◽  
Yang Liu ◽  
Qiong Liu ◽  
Faqi Zhan ◽  
...  
Keyword(s):  
Light Absorption ◽  
Photoelectron Spectroscopy ◽  
Seed Layer ◽  
Electrochemical Impedance ◽  
Solid Phase ◽  
Zno Nanorods ◽  
Phase Method ◽  
Photoelectrochemical Performance ◽  
Electrochemical Impedance Spectra ◽  
X Ray

S-doped C3N4 quantum dots (SCNQDs) were synthesized successfully by a low-temperature solid-phase method. The as-synthesised SCNQDs were decorated on ZnO nanorods by a dipping method. The ZnO nanorod films were prepared through a two-stage method, including pulse electrodeposition for depositing ZnO seed layer on fluorine doping SnO2 glass (FTO) and chemical bath for growing ZnO nanorods on the ZnO seed layer. The prepared samples were characterized via scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS). The photoelectrochemical performances of the prepared samples were estimated using linear sweep voltammograms, electrochemical impedance spectra (EIS), Mott–Schottky, transient photocurrent and incident photon-to-current conversion efficiency (IPCE). The results show that the light absorption edge of the prepared SCNQDs increases from 326[Formula: see text]nm (CNQDs) to 349[Formula: see text]nm after S doping. The CNQD decorated ZnO photoanode film exhibits 1.34 times as high photocurrent as bare ZnO photoanode film. Importantly, the photocurrent increased to 1.79 times than bare ZnO photoanode film by S doping at 1.0[Formula: see text]V (versus Ag/AgCl), which is attributed to a wider light absorption of SCNQDs and a better efficiency of electron transfer in the interface between SCNQDs and ZnO.

scholarly journals Enhanced Electrochemical Performances of Cobalt-Doped Li2MoO3 Cathode Materials

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 843 ◽  
Author(s):  
Zhiyong Yu ◽  
Jishen Hao ◽  
Wenji Li ◽  
Hanxing Liu
Keyword(s):  
Cathode Materials ◽  
Photoelectron Spectroscopy ◽  
Solid Phase ◽  
Phase Method ◽  
Electrochemical Performances ◽  
X Ray ◽  
Electrochemical Tests ◽  
Co Doping ◽  
Solid Phase Method ◽  
Better Than

Co-doped Li2MoO3 was successfully synthesized via a solid phase method. The impacts of Co-doping on Li2MoO3 have been analyzed by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) measurements. The results show that an appropriate amount of Co ions can be introduced into the Li2MoO3 lattices, and they can reduce the particle sizes of the cathode materials. Electrochemical tests reveal that Co-doping can significantly improve the electrochemical performances of the Li2MoO3 materials. Li2Mo0.90Co0.10O3 presents a first-discharge capacity of 220 mAh·g−1, with a capacity retention of 63.6% after 50 cycles at 5 mA·g−1, which is much better than the pristine samples (181 mAh·g−1, 47.5%). The enhanced electrochemical performances could be due to the enhancement of the structural stability, and the reduction in impedance, due to the Co-doping.

scholarly journals Fabrication of Hybrid Catalyst ZnO Nanorod/α-Fe2O3 Composites for Hydrogen Evolution Reaction

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 356
Author(s):  
Kasimayan Uma ◽  
Elavarasan Muniranthinam ◽  
Siewhui Chong ◽  
Thomas C.-K Yang ◽  
Ja-Hon Lin
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Nickel Foam ◽  
Zno Nanorods ◽  
Synergetic Effect ◽  
Zno Nanorod ◽  
Fe2o3 Nanoparticles ◽  
X Ray

This report presents the synthesis of ZnO nanorod/α-Fe2O3 composites by the hydrothermal method with different weight percentages of α-Fe2O3 nanoparticles. The as-synthesized nanorod composites were characterized by different techniques, such as X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). From our results, it was found that the ZnO/α-Fe2O3 (3 wt%) nanorod composites exhibit a higher hydrogen evolution reaction (HER) activity when compared to other composites. The synergetic effect between ZnO and (3 wt%) of α-Fe2O3 nanocomposites resulted in a low onset potential of −125 mV, which can effectively produce more H2 than pure ZnO. The H2 production rate over the composite of ZnO/α-Fe2O3 (3 wt%) clearly shows a significant improvement in the photocatalytic activity in the heterojunction of the ZnO nanorods and α-Fe2O3 nanoparticles on nickel foam.

Synthesis and Characterization of Li0.97K0.03FePO4/Graphene Composites by Carbonthermal Reduction Method

2014 ◽  
Vol 687-691 ◽  
pp. 4327-4330
Author(s):  
Yan Wang ◽  
Zhe Sheng Feng ◽  
Lu Lin Wang ◽  
Jin Ju Chen ◽  
Zhen Yu He
Keyword(s):  
Discharge Capacity ◽  
Photoelectron Spectroscopy ◽  
Reduction Method ◽  
Electrochemical Impedance ◽  
Impedance Spectra ◽  
X Ray Diffraction ◽  
Capacity Retention ◽  
Electrochemical Impedance Spectra ◽  
X Ray

Li0.97K0.03FePO4 and Li0.97K0.03FePO4/graphene composites were synthesized by carbothermal reduction method using acetylene black as carbon source. The structure and electrochemical properties of the prepared materials were investigated with X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, galvanostatic charge and discharge and electrochemical impedance spectra tests. The results indicated that K doping improves the cyclic stability of samples, the addition of small amounts of graphene results in better electronic properties on sample. Li0.97K0.03FePO4/graphene showed discharge capacity of 158.06 and 90.55 mAh g-1 at 0.1 C and 10 C, respectively. After the 50 cycle test at different rates, the reversible discharge capacity at 0.1 C was 158.58 mAh g-1, indicating the capacity retention ratio of 100.32%.

scholarly journals Pentavalent Vanadium Species as Potential Corrosion Inhibitors of Al2Cu Intermetallic Phase in the Sulfuric(VI) Acid Solutions

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1946 ◽  
Author(s):  
Przemysław Kwolek ◽  
Barbara Kościelniak ◽  
Magdalena Wytrwal-Sarna
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Intermetallic Phase ◽  
Open Circuit ◽  
Acid Solutions ◽  
Scanning Calorimetry ◽  
Electrochemical Impedance Spectra ◽  
X Ray

The objective of this work was to test vanadium isopolyoxoanions as potential corrosion inhibitors of the intermetallic phase Al2Cu in sulfuric acid solutions at pH = 1.3 and 2.5. The intermetallic was melted in an electric arc furnace. Its phase composition was confirmed using X-ray diffraction, light microscopy, and differential scanning calorimetry. Then Al2Cu corrosion kinetics was studied. Chemical composition of the solution after corrosion was determined using inductively coupled plasma-optical emission spectroscopy. The surface of corroded specimens was analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy. Subsequent electrochemical studies involved determination of open-circuit potential, electrochemical impedance spectra, and polarization curves. It was found that the Al2Cu phase corrodes selectively and vanadium isopolyoxoanions increase this process both at pH = 1.3 and 2.5 with two exceptions. Corrosion inhibition was observed for 100 and 200 mM of Na3VO4 at pH 1.3, with inhibition efficiency 78% and 62% respectively, due to precipitation of V2O5.

scholarly journals Cr-Doped Li2ZnTi3O8 as a High Performance Anode Material for Lithium-Ion Batteries

2021 ◽  
Vol 8 ◽  
Author(s):  
Xianguang Zeng ◽  
Jing Peng ◽  
Huafeng Zhu ◽  
Yong Gong ◽  
Xi Huang
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electrochemical Impedance ◽  
Performance Testing ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Cycle Performance ◽  
Phase Method ◽  
Rate Performance ◽  
X Ray

Li2ZnTi2.9Cr0.1O8 and Li2ZnTi3O8 were synthesized by the liquid phase method and then studied comparatively using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), galvanostatic charge–discharge testing, cyclic stability testing, rate performance testing, and electrochemical impedance spectroscopy (EIS). The results showed that Cr-doped Li2ZnTi3O8 exhibited much improved cycle performance and rate performance compared with Li2ZnTi3O8. Li2ZnTi2.9Cr0.1O8 exhibited a discharge ability of 156.7 and 107.5 mA h g−1 at current densities of 2 and 5 A g−1, respectively. In addition, even at a current density of 1 A g−1, a reversible capacity of 162.2 mA h g−1 was maintained after 200 cycles. The improved electrochemical properties of Li2ZnTi2.9Cr0.1O8 are due to its increased electrical conductivity.

scholarly journals Layered MoS2 Grown on Anatase TiO2 {001} Promoting Interfacial Electron Transfer to Enhance Photocatalytic Evolution of H2 From H2S

2020 ◽  
Vol 1 ◽  
Author(s):  
Qing Cai ◽  
Fang Wang ◽  
Jianglai Xiang ◽  
Meng Dan ◽  
Shan Yu ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Electrochemical Impedance ◽  
High Catalytic Activity ◽  
Interfacial Electron Transfer ◽  
Green Technologies ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Production Of Hydrogen

The treatment of hazardous hydrogen sulfide (H2S) via photocatalysis technology has been known as one of the most promising green technologies. Photocatalytic production of hydrogen (H2) from H2S by two-dimensional (2D) semiconductor materials has gathered great attention owing to its large surface area and high catalytic activity. In this work, layered MoS2 has been successfully grown on TiO2 {001} surface to fabricate the 2D MoS2/TiO2 {001} composites for H2 evolution from H2S, which can be confirmed by the X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests. Band structures and UV-Vis spectra provide important evidences that MoS2 loading can significantly narrow the band gap and broaden the light absorbance into the visible light region. Electron transfer is obviously visualized at the interface of MoS2/TiO2, resulting in the built-in potential from TiO2 to MoS2, which is determined by the density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) test. Consequently, the photo-induced electrons and holes are accumulated at the sides of TiO2 and MoS2 under the illumination, respectively, which largely promote the interfacial electron transfer and prolong the lifetime of photo-generated electrons that participate in the photocatalytic reactions of H2 evolution from H2S. This efficient separation of photo-induced carriers can be further proved by photoluminescence (PL) spectra, photocurrent responses, and electrochemical impedance spectra. As a result, the photocatalytic activity of H2 evolution is largely increased by 9.4 times compared to the pristine TiO2. This study could offer a new and facile way to design highly efficient 2D photocatalysts for the application of H2S treatment.

scholarly journals High Electrochemical Performance of Nanotube Structured ZnS as Anode Material for Lithium–Ion Batteries

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1537 ◽  
Author(s):  
Wen Zhang ◽  
Junfan Zhang ◽  
Yan Zhao ◽  
Taizhe Tan ◽  
Tai Yang
Keyword(s):  
Lithium Ion Batteries ◽  
Discharge Capacity ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Zno Nanorods ◽  
Sorption Isotherms ◽  
Lithium Ion ◽  
Chemical Compositions ◽  
X Ray ◽  
Eis Measurements

By using ZnO nanorods as an ideal sacrificial template, one-dimensional (1-D) ZnS nanotubes with a mean diameter of 10 nm were successfully synthesized by hydrothermal method. The phase composition and microstructure of the ZnS nanotubes were characterized by using XRD (X-ray diffraction), SEM (scanning electron micrograph), and TEM (transmission electronic microscopy) analysis. X-ray photoelectron spectroscopy (XPS) and nitrogen sorption isotherms measurements were also used to study the information on the surface chemical compositions and specific surface area of the sample. The prepared ZnS nanotubes were used as anode materials in lithium-ion batteries. Results show that the ZnS nanotubes deliver an impressive prime discharge capacity as high as 950 mAh/g. The ZnS nanotubes also exhibit an enhanced cyclic performance. Even after 100 charge/discharge cycles, the discharge capacity could still remain at 450 mAh/g. Moreover, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were also carried out to evaluate the ZnS electrodes.

Impact of Rutile Fraction on TiO2 Visible-Light Absorption and Visible-Light-Induced Photocatalytic Activity

2018 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
ana caetano ◽  
nejc rozman ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Solid Phase ◽  
Diffraction Method ◽  
Band Alignment ◽  
Quantitative Phase Analysis ◽  
Transmission Microscopy ◽  
Visible Light Absorption ◽  
X Ray

<div>Titanium dioxide is by far the most utilised semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile−anatase mixture would improve its visible-light absorption.</div><div>In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. </div><div>The structural characterisation was done via advanced X-ray diffraction method, namely the Rietveld-RIR method, to attain a full quantitative phase analysis of the specimens. The microstructure was also investigated via an advanced X-ray method, the whole powder pattern modelling. These methods were validated combining advanced aberration-corrected scanning transmission microscopy and high-resolution electron energy-loss spectroscopy. The photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range.</div><div>Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light?</div><div>We tried to give a reply to that question.</div><div>Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-induced catalytic activity (i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects). That is: not photocatalysis <i>sensu-strictu</i>.</div><div>On the other hand, the gas-solid phase results showed that a higher amount of the rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for an actual photocatalytic oxidation of isopropanol.</div>

Few-Layered MoS2 Nanostructures for Highly Efficient Visible Light Photocatalysis

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650114 ◽  
Author(s):  
Dan Li ◽  
Jianwei Li ◽  
Caiqin Han ◽  
Xinsheng Zhao ◽  
Haipeng Chu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Hole Pair

Few-layered MoS2 nanostructures were successfully synthesized by a simple hydrothermal method without the addition of any catalysts or surfactants. Their morphology, structure and photocatalytic activity were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electrochemical impedance spectra and UV-Vis absorption spectroscopy, respectively. These results show that the MoS2 nanostructures synthesized at 180[Formula: see text]C exhibit an optimal visible light photocatalytic activity (99%) in the degradation of Rhodamine B owing to the relatively easier adsorption of pollutants, higher visible light absorption and lower electron–hole pair recombination.

Ternary Composite of Molybdenum Disulfide-Graphene Oxide-Polyaniline for Supercapacitor

2021 ◽  
Author(s):  
Ke Qu ◽  
Yuqi Bai ◽  
Miao Deng
Keyword(s):  
Graphene Oxide ◽  
Molybdenum Disulfide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Light Emitting Diode ◽  
Rate Capability ◽  
Energy Storage And Conversion ◽  
Carbon Paper ◽  
Power Sources ◽  
X Ray

Abstract The ever-increasing need for small and lightweight power sources for use in portable or wearable electronic devices has spurred the development of supercapacitors as a promising energy storage and conversion system. In this work, a simple, facile and easy-to-practice method has been developed to employ carbon paper (CP) as the support to coat molybdenum disulfide (MoS2) and graphene oxide (GO), followed by electrodeposition of polyaniline (PANI) to render CP/MoS2-GO-PANI. The preparation parameters, such as amounts of MoS2, GO and number of aniline electropolymerization cycles, have been optimized to render CP/MoS2-GO-PANI the best capacitive performance. The as-prepared optimal CP/MoS2-GO-PANI is characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The supercapacitive properties of CP/MoS2-GO-PANI as an electrode have been evaluated electrochemically via cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy testing. CP/MoS2-GO-PANI delivers a specific capacitance of 255.1 F/g at 1.0 A/g and exhibits excellent rate capability under larger current densities. Moreover, a symmetrical supercapacitor is assembled and three are connected in series to power a light-emitting diode for ~15 minutes, demonstrating the promising application potential of CP/MoS2-GO-PANI-based supercapacitor.

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