Photocatalytic H2 production on trititanate nanotubes coupled with CdS and platinum nanoparticles under visible light: revisiting H2 production and material durability

2017 ◽  
Vol 198 ◽  
pp. 419-431 ◽  
Author(s):  
Hyunwoong Park ◽  
Hsin-Hung Ou ◽  
Minju Kim ◽  
Unseock Kang ◽  
Dong Suk Han ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
H2 Production ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Thermal Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Detailed Surface ◽  
Efficient Charge

The photocatalytic production of molecular hydrogen (H2) on ternary composites of Pt, CdS, and sodium trititanate nanotubes (NaxH2−xTi3O7, TNTs) is examined in an aqueous 2-propanol (IPA) solution (typically 5 vol%) at a circum-neutral pH under visible light (λ > 420 nm). The H2 production rates are dependent on the Pt-loading level, and the optimum production rate in the Pt/CdS/TNTs is approximately six times higher than that in Pt/CdS/TiO2. A D2O solution containing 5 vol% IPA leads only to the production of D2 molecules, whereas increasing the IPA amount to 30 vol% leads to the production of DH molecules. This indicates that the Pt/CdS/TNTs composites enable H2 production via true water splitting under our typical experimental conditions. X-ray photoelectron spectroscopy (XPS) analyses of the as-synthesized Pt/CdS/TNTs and those used for 6 and 12 h show that metallic Pt on the CdS/TNTs is less susceptible to oxidation than Pt on CdS/TiO2. In addition, photocorrosion of CdS (i.e., sulfate formation) is significantly inhibited during the photocatalytic H2 production reactions in the Pt/CdS/TNTs because of the efficient charge transfer via the TNTs framework. The Pt/CdS/TNTs samples are thermally more stable than Pt/CdS/TiO2 and CdS/TNTs, effectively inhibiting the formation of CdO during the thermal synthesis. Detailed surface characterizations of the as-synthesized ternary composites are performed using X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, and XPS.

FeYO3@rGO nanocomposites: Synthesis, characterization and application in photooxidative degradation of atrazine under visible light

2021 ◽  
Vol 11 (5) ◽  
pp. 706-716
Author(s):  
Nada D. Al-Khthami ◽  
Tariq Altalhi ◽  
Mohammed Alsawat ◽  
Mohamed S. Amin ◽  
Yousef G. Alghamdi ◽  
...  
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Structural Surface ◽  
Adsorption Desorption

Different organic pollutants have been remediated photo catalytically by applying perovskite photocatalysts. Atrazine (ATR) is a pesticide commonly detected as a pollutant in drinking, surface and ground water. Herein, FeYO3@rGO heterojunction was synthesized and applied for photooxidation decomposition of ATR. First, FeYO 3nanoparticles (NPs) were prepared via routine sol-gel. After that, FeYO3 NPs were successfully incorporated with different percentages (5, 10, 15 and 20 wt.%) of reduced graphene oxide (rGO) in the synthesis of novel FeYO3@rGO photocatalyst. Morphological, structural, surface, optoelectrical and optical characteristics of constructed materials were identified via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), adsorption/desorption isotherms, diffusive reflectance (DR) spectra, and photoluminescence response (PL). Furthermore, photocatalytic achievement of the constructed materials was evaluated via photooxidative degradation of ATR. Various investigations affirmed the usefulness of rGO incorporation on the advancement of formed photocatalysts. Actually, novel nanocomposite containing rGO (15 wt.%) possessed diminished bandgap energy, as well as magnified visible light absorption. Furthermore, such nanocomposite presented exceptional photocatalytic achievement when exposed to visible light as ATR was perfectly photooxidized over finite amount (1.6 g · L-1) from the optimized photocatalyst when illuminated for 30 min. The advanced photocatalytic performance of constructed heterojunctions could be accredited mainly to depressed recombination amid induced charges. The constructed FeYO3@rGO nanocomposite is labelled as efficient photocatalyst for remediation of herbicides from aquatic environments.

scholarly journals Biomass-Derived Activated Carbon as a Catalyst for the Effective Degradation of Rhodamine B dye

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 926
Author(s):  
Shamim Ahmed Hira ◽  
Mohammad Yusuf ◽  
Dicky Annas ◽  
Hu Shi Hui ◽  
Kang Hyun Park
Keyword(s):  
Electron Microscopy ◽  
Activated Carbon ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
High Specific Surface Area ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron

Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future.

scholarly journals Preparation of g-C3N4/MoS2 Composite Material and Its Visible Light Catalytic Performance

2021 ◽  
Author(s):  
Yu Fan ◽  
Yan-ning Yang ◽  
Chen Ding
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Photogenerated Electron ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Calcination Method

Abstract The g-C3N4 nanosheet was prepared by calcination method, the MoS2 nanosheet was prepared by hydrothermal method. The g-C3N4/MoS2 composites were prepared by ultrasonic composite in anhydrous ethanol. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis), and photoluminescence (PL) techniques were used to characterize the materials. The photocatalytic degradation of Rhodamine B (Rh B) by g-C3N4/MoS2 composites with different mass ratios was investigated under visible light. The results show that a small amount of MoS2 combined with g-C3N4 can significantly improve photocatalytic activity. The g-C3N4/MoS2 composite with a mass ratio of 1:8 has the highest photocatalytic activity, and the degradation rate of Rh B increases from 50% to 99.6%. The main reason is that MoS2 and g-C3N4 have a matching band structure. The separation rate of photogenerated electron-hole pairs is enhanced. So the g-C3N4/MoS2 composite can improve the photocatalytic activity. The photocatalytic mechanism was proposed through the active matter capture experiment.

scholarly journals Improved Visible Light Photocatalytic Activity for TiO2Nanomaterials by Codoping with Zinc and Sulfur

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Qianzhi Xu ◽  
Xiuying Wang ◽  
Xiaoli Dong ◽  
Chun Ma ◽  
Xiufang Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sunlight Irradiation ◽  
X Ray ◽  
Transmission Electron ◽  
Photoinduced Charge

S/Zn codoped TiO2nanomaterials were synthesized by a sol-gel method. X-ray diffraction, UV-vis diffuse reflectance spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the morphology, structure, and optical properties of the prepared samples. The introduction of Zn and S resulted in significant red shift of absorption edge for TiO2-based nanomaterials. The photocatalytic activity was evaluated by degrading reactive brilliant red X-3B solution under simulated sunlight irradiation. The results showed S/Zn codoped TiO2exhibited higher photocatalytic activity than pure TiO2and commercial P25, due to the photosynergistic effect of obvious visible light absorption, efficient separation of photoinduced charge carriers, and large surface area. Moreover, the content of Zn and S in the composites played important roles in photocatalytic activity of TiO2-based nanomaterials.

scholarly journals Comparative Study of the Photocatalytic Hydrogen Evolution over Cd1−xMnxS and CdS-β-Mn3O4-MnOOH Photocatalysts under Visible Light

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 355
Author(s):  
Ksenia O. Potapenko ◽  
Anna Yu. Kurenkova ◽  
Andrey V. Bukhtiyarov ◽  
Evgeny Yu. Gerasimov ◽  
Svetlana V. Cherepanova ◽  
...  
Keyword(s):  
Solid Solution ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Manganese Salts

A series of solid solutions of cadmium and manganese sulfides, Cd1−xMnxS (x = 0–0.35), and composite photocatalysts, CdS-β-Mn3O4-MnOOH, were synthesized by precipitation with sodium sulfide from soluble cadmium and manganese salts with further hydrothermal treatment at 120 °C. The obtained photocatalysts were studied by the X-ray diffraction method (XRD), UV-vis diffuse reflectance spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2 low temperature adsorption. The photocatalysts were tested in hydrogen production using a Na2S/Na2SO3 aqueous solution under visible light (λ = 450 nm). It was shown for the first time that both kinds of photocatalysts possess high activity in hydrogen evolution under visible light. The solid solution Cd0.65Mn0.35S has an enhanced photocatalytic activity due to its valence and conduction band position tuning, whereas the CdS-β-Mn3O4-MnOOH (40–60 at% Mn) samples were active due to ternary heterojunction formation. Further, the composite CdS-β-Mn3O4-MnOOH photocatalyst had much higher stability in comparison to the Cd0.65Mn0.35S solid solution. The highest activity was 600 mmol g−1 h−1, and apparent quantum efficiency of 2.9% (λ = 450 nm) was possessed by the sample of CdS-β-Mn3O4-MnOOH (40 at% Mn).

Cobalt and sulfur co-doped TiO2 nanostructures with enhanced photo-response properties for photocatalyst

2017 ◽  
Vol 10 (05) ◽  
pp. 1750061 ◽  
Author(s):  
Qiu Jin ◽  
Chaoyin Nie ◽  
Qianqian Shen ◽  
Yusheng Xu ◽  
Yanzhong Nie
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Response Threshold ◽  
X Ray Diffraction ◽  
X Ray ◽  
Valence States ◽  
Transmission Electron ◽  
Photo Response ◽  
Co Doped

Cobalt (Co) and sulfur (S) co-doped titanium dioxide (TiO2) catalysts were synthesized via sol–gel method. The structure of TiO2was characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The valence states of elements were studied by X-ray photoelectron spectroscopy (XPS), and the optical-absorption properties of the catalysts were tested using the ultraviolet–visible (UV–Vis) spectrophotometer. The results showed that the grain sizes of Co and S co-doped TiO2 decreased with the increase of Co and S doping concentration within a certain range, and then the catalysts had obvious red shift on the absorption of visible light. Sample (2%Co–5%S–TiO2) showed excellent light absorption characteristics and the photo-response threshold increased significantly to about 760[Formula: see text]nm. Also, the further degradation test under visible light shows the 2%Co–5%S-TiO2 sample exhibit apparently improved degradation efficiency for Rhodamine B compared to the undoped one.

Dye-Sensitized-Assisted, Enhanced Photocatalytic Activity of TiO2/Bi4V2O11

NANO ◽  
2018 ◽  
Vol 13 (03) ◽  
pp. 1850028 ◽  
Author(s):  
Mengjun Liang ◽  
Zhiyuan Yang ◽  
Ying Mei ◽  
Haoran Zhou ◽  
Shuijin Yang
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Sensitized ◽  
Transmission Electron ◽  
Efficient Charge ◽  
Degradation Activity ◽  
Adsorption Desorption

In this study, the TiO2/Bi4V2O[Formula: see text] nanocomposite photocatalysts were prepared by loading different amount of TiO2 nanoparticles onto the surface of Bi4V2O[Formula: see text] nanospheres via a facile hydrothermal method. Afterwards, the as-synthesized samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), N2 adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS) and photocurrent techniques. The optimal TiO2/Bi4V2O[Formula: see text] composite with 20[Formula: see text]wt.% TiO2 loading (TB2) exhibited the best photocatalytic activity, which could degrade almost RhB completely within 30[Formula: see text]min under visible light irradiation. The enhanced photocatalytic activity of TiO2/Bi4V2O[Formula: see text] composites for RhB degradation could be mainly ascribed to the efficient charge separation over dye-induced sensitized and the increased specific surface area. Also, the photocatalytic activities of TiO2/Bi4V2O[Formula: see text] for CIP degradation were tested. After five consecutive recycling experiments, the photocatalytic degradation activity of TB2 could still reach 99% which indicated that the catalysts had superior stability. Based on the experimental and bandgap calculations, a possible photocatalytic mechanism of TiO2/Bi4V2O[Formula: see text] for RhB degradation was proposed.

scholarly journals Facile Synthesis of CeO2 Blended CoWO4 Nanocomposites For High Photocatalytic Performance And Investigation of Their Antimicrobial Activity

2021 ◽  
Author(s):  
S. Selvi ◽  
N. Jayamani ◽  
D. Barathi
Keyword(s):  
Visible Light ◽  
Photocatalytic Performance ◽  
Light Exposure ◽  
Photo Luminescence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Visible Light Active ◽  
Efficient Charge ◽  
Diffusion Scheme

Abstract In this work, novel CeO2/CoWO4 hetero structured nanocomposites (NCs) was synthesized via a hydrothermal method. X-ray diffraction (XRD), high-resolution transmission electron microscopy(HRTEM), UV-VisDRS and photo luminescence (PL) spectroscopy were categorized herein to gain the crystal structure, deep morphology, optical assets, and charge separation of the as-produced photocatalysts (PCs)respectively. Related by the pristine CoWO4,CeO2 and CeO2/CoWO4 photocatalyst was considered by enriched activity of them ethylene blue (MB)aqueous dye photodegradation under visible light exposure. Chiefly, the photodegradation efficacy of as-attained CeO2/CoWO4 photocatalyst exposed the premier decomposition ratio (92.5%) of MB dyein105 min among all samples, which was noticeably 1.8 and 2.2 folds over the pristine CeO2 (43 %) and CoWO4(60 %), separately. Likewise, the CeO2/CoWO4 PCs sustained satisfactory activity even after 4sequentialrecycling runs, signifying its great photocatalytic steadiness and robustness. Hence the ensuing superior PCs preferred the further efficient charge (e−-h+) separation, solid visible light fascination, and worthy interfacial energy transfer leads amid CoWO4 and CeO2nanoparticles (NPs).A likely mechanism liable for photodegradation was eventually projected. The synergistic things of antibacterial motion via CeO2/CoWO4 NCs were probed by the weld diffusion scheme. Thus, effort finding deals with a novel avenue for the growth of stable and proficient visible-light active PCs for environmental purification.

Novel Nanoarchitechtonics Olive-Like Pd/BiVO4 for the Degradation of Gaseous Formaldehyde Under Visible Light Irradiation

2020 ◽  
Vol 20 (5) ◽  
pp. 2689-2697 ◽  
Author(s):  
Zhen Zhu ◽  
Wei-Gang Hong ◽  
Chin-Yuan Chen ◽  
Ren-Jang Wu
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Irradiation Time ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Formaldehyde Degradation ◽  
Gaseous Formaldehyde

In this research, olive-like Pd/BiVO4 was successfully prepared through a facile hydrothermal coreduction method for the photocatalytic degradation of formaldehyde under visible light irradiation. The structure, composition, and optical properties of the as-prepared Pd/BiVO4 were characterized through X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectrophotometry, X-ray photoelectron spectroscopy, and photoluminescence. In addition, the photocatalytic activities of Pd/BiVO4 were evaluated through the photodegradation of formaldehyde. The experimental results demonstrated that the degradation efficiency of formaldehyde increased with increasing irradiation time. Moreover, 1.0 wt% Pd/BiVO4 exhibited the highest photocatalytic performance for formaldehyde degradation in 180 min, with the formaldehyde degradation rate as high as 87.5%.

scholarly journals Simultaneous adsorption and reduction of hexavalent chromium on biochar-supported nanoscale zero-valent iron (nZVI) in aqueous solution

2020 ◽  
Vol 82 (7) ◽  
pp. 1339-1349
Author(s):  
Fengfeng Ma ◽  
Bakunzibake Philippe ◽  
Baowei Zhao ◽  
Jingru Diao ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Zero Valent Iron ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Pseudo Second Order

Abstract Flax straw biochar (FSBC)-supported nanoscale zero-valent iron (nZVI) composite (nZVI-FSBC) combining the advantages of nZVI and biochar was synthesized and tested for Cr(VI) removal efficiency from aqueous solution. Surface morphology and structure of FSBC and nZVI-FSBC were characterized by scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller techniques, which help to clarify the mechanism of Cr(VI) removal from aqueous solution. The adsorption of Cr(VI) onto FSBC and nZVI-FSBC was best described by the pseudo-second-order and the Sips model. Compared with FSBC, nZVI-FSBC remarkably improved the performance in removing Cr(VI) under identical experimental conditions. Due to the collaborative effect of adsorption and reduction of nZVI-FSBC, the adsorption capacity of nZVI-FSBC for Cr(VI) is up to 186.99 mg/g. The results obtained by XPS, XRD, and FTIR confirmed that adsorption and reduction dominated the processes of Cr(VI) removal by nZVI-FSBC. As a supporter, FSBC not only improved the dispersion of nZVI, but also undertook the adsorption task of Cr(VI) removal. The surface oxygen-containing functional groups of nZVI-FSBC mainly participated in the adsorption part, and the nZVI promoted the Cr(VI) removal through the redox reactions. These observations indicated that the nZVI-FSBC can be considered as potential adsorbents to remove Cr(VI) for environment remediation.

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