Hydrothermal Synthesis of Band Gap-Tunable Oxygen-Doped g-C3N4 with Outstanding “Two-Channel” Photocatalytic H2O2 Production Ability Assisted by Dissolution–Precipitation Process

NANO ◽  
2019 ◽  
Vol 14 (02) ◽  
pp. 1950023 ◽  
Author(s):  
Hui Wang ◽  
Yuanhao Guan ◽  
Shaozheng Hu ◽  
Yanbo Pei ◽  
Wentao Ma ◽  
...  
Keyword(s):  
Band Gap ◽  
Carbon Nitride ◽  
Separation Efficiency ◽  
Electrochemical Impedance ◽  
Band Gap Energy ◽  
Precipitation Process ◽  
H2o2 Production ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Photogenerated Electrons

Here, band gap-tunable oxygen-doped graphitic carbon nitride (g-C3N4) with outstanding “two-channel” photocatalytic H2O2 production ability was prepared via hydrothermal treatment assisted by dissolution–precipitation process. XRD, N2 adsorption, UV–Vis, Fourier-transform infrared spectra, SEM, electrochemical impedance spectra, XPS and photoluminescence were used to characterize the obtained catalysts. The photocatalytic H2O2 production ability of as-prepared catalyst was investigated. The results show that oxygen doping not only changes the morphology of catalyst, decreases the band gap energy and promotes the separation efficiency of photogenerated electrons and holes, but also tunes the CB and VB potentials. As-prepared oxygen-doped g-C3N4 displays a H2O2 concentration of 3.8[Formula: see text]mmol[Formula: see text]L[Formula: see text], more than 7.6 times higher than that of neat g-C3N4. Because of the shift of CB and VB potentials, not only the CB electrons of oxygen-doped g-C3N4 reduce O2 to form H2O2, but also the VB holes can oxidize OH− to form [Formula: see text]OH, which subsequently react with each other to form H2O2. Such “two-channel pathway” causes the remarkably promoted H2O2 production ability.

scholarly journals ZnO@Bi5O7I Heterojunction Derived from ZIF-8@BiOI for Enhanced Photocatalytic Activity under Visible Light

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 508
Author(s):  
Jijun Tang ◽  
Zhengzhou Duan ◽  
Qinyun Xu ◽  
Chuwen Li ◽  
Dongmei Hou ◽  
...  
Keyword(s):  
Fluorescence Spectra ◽  
Separation Efficiency ◽  
Electrochemical Impedance ◽  
Diffuse Reflectance Spectroscopy ◽  
Removal Rate ◽  
Bet Surface Area ◽  
Impedance Spectra ◽  
X Ray Diffraction ◽  
Electrochemical Impedance Spectra ◽  
New Approach

In the study, ZIF-8@BIOI composites were synthesized by the hydrothermal method and then calcined to acquire the ZnO@Bi5O7I composite as a novel composite for the photocatalytic deterioration of the antibiotic tetracycline (TC). The prepared ZnO@Bi5O7I composites were physically and chemically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmet–Teller (BET) surface area, UV–Vis diffuse reflectance spectroscopy (DRS), emission fluorescence spectra, transient photocurrent response, electrochemical impedance spectra and Mott–Schottky. Among the composites formed an n–n heterojunction, which increased the separation efficiency of electrons and holes and the efficiency of charge transfer. After the photocatalytic degradation test of TC, it showed that ZnO@Bi5O7I (2:1) had the best photodegradation effect with an 86.2% removal rate, which provides a new approach to the treatment of antibiotics such as TC in wastewater.

Performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag Composite Cathode Materials for IT-SOFCs

2011 ◽  
Vol 311-313 ◽  
pp. 2309-2314 ◽  
Author(s):  
Wen Xia Zhu ◽  
Zhe Lü ◽  
Le Xin Wang ◽  
Xiao Yan Guan ◽  
Xin Yan Zhang
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Electrode Polarization ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Composite Cathodes ◽  
Reduced Temperature ◽  
Resistance Value

°Abstract. In order to develop new cathodes for reduced temperature SOFCs, Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag composite cathode was investigated in intermediate-temperature Solid Oxide Fuel Cells (IT-SOFCs). The XRD results suggested that no chemical reactions between BSCF and Ag in the composite cathode were found. The resistance measurements showed that the addition of Ag into BSCF improved electrical conductivity of pure BSCF, and the improved conductivity resulted in attractive cathode performance. In addition, electrochemical impedance spectra exhibited the better performance of BSCF-Ag composite cathodes than pure BSCF, e.g., the polarization resistance value of BSCF-Ag was only 0.36Ω cm2 at 650°C, which was nearly 80% lower than that of BSCF electrode. Polarization curves showed the overpotential decreased with the addition of Ag. The current density value of BSCF-Ag was 0.88Acm-2 under –120mV, about five times of that BSCF measured at 650°C. As a summary, compared to a pure BSCF cathode, it was found that adding Ag in the cathode enhanced the BSCF performance significantly.

Interaction between Sodium Molybdate and FSWed Wled of 5083 Effected by Time

2013 ◽  
Vol 699 ◽  
pp. 645-649
Author(s):  
Chang Bin Shen
Keyword(s):  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Sodium Molybdate ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Friction Stir ◽  
Base Materials ◽  
Corrosion Behaviors ◽  
5083 Aluminum Alloy

Similar welds composed of 5083 were produced by friction stir welding. In the solution of 0.2 M NaHSO3 and 0.6 M NaCl, with the addition of a given concentration sodium molybdate as the inhibitor, the electrochemical corrosion behaviors of the friction stir welds (FSW) and 5083 were comparatively investigated by potentiodynamic polarization curve tests and electrochemical impedance spectra (EIS) at the ambient temperature for different test periods. The results indicated that : with the extension of period, the inhibition efficiencies (IE) for both the weld and 5083 base materials enhanced, at the same period, the inhibition efficiency (IE) for the weld was beyond that for 5083 base materials, sodium molybdate may be thought of as an effective inhibitor for 5083 aluminum alloy, the interaction between inhibitor and weld is stronger than that between inhibitor and base materials.

An analysis of drifts and nonlinearities in electrochemical impedance spectra

2011 ◽  
Vol 56 (22) ◽  
pp. 7467-7475 ◽  
Author(s):  
Niket S. Kaisare ◽  
Vimala Ramani ◽  
Karthik Pushpavanam ◽  
S. Ramanathan
Keyword(s):  
Electrochemical Impedance ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra

scholarly journals Optimized Synthesis Temperature and Time to Obtain Crystalline Carbon Nitride with Enhanced Photocatalytic Activity for Phenol Degradation

2020 ◽  
Vol 20 (6) ◽  
pp. 1392
Author(s):  
Leny Yuliati ◽  
Mohd Hayrie Mohd Hatta ◽  
Siew Ling Lee ◽  
Hendrik Oktendy Lintang
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Band Gap ◽  
Surface Area ◽  
Carbon Nitride ◽  
Phenol Degradation ◽  
Synthesis Temperature ◽  
Band Gap Energy ◽  
Synthesis Time ◽  
Gap Energy

In this work, the crystalline carbon nitride photocatalysts were synthesized by an ionothermal technique with varied synthesis temperature of 500, 550, and 600 °C, and synthesis time of 2, 4, and 6 h. Fourier transform infrared spectra showed the successful formation of the prepared carbon nitrides from their characteristic vibration peaks. X-ray diffraction patterns suggested that the same phase of poly(triazine imide) and heptazine could be observed, but with different crystallinity. The optical properties showed that different temperatures and synthesis time resulted in the different band gap energy (2.72–3.02 eV) as well as the specific surface area (24–73 m2 g–1). The transmission electron microscopy image revealed that the crystalline carbon nitride has a near-hexagonal prismatic crystallite size of about 50 nm. Analysis by high-performance liquid chromatography showed that the best photocatalytic activity for phenol degradation under solar light simulator was obtained on the crystalline carbon nitride prepared at the 550 °C for 4 h, which would be due to the high crystallinity, suitable low band gap energy (2.82 eV), and large specific surface area (73 m2 g–1). Controlling both the temperature and synthesis time is shown to be important to obtain the best physicochemical properties leading to high activity.

Sign in / Sign up

Export Citation Format

Share Document