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排序方式: 共有1125条查询结果,搜索用时 19 毫秒
1.
《International Journal of Hydrogen Energy》2022,47(69):29771-29780
Conjugated polymers have emerged as a promising class of organic photocatalysts for photocatalytic hydrogen evolution from water splitting due to their adjustable chemical structures and electronic properties. However, developing highly efficient organic polymer photocatalysts with high photocatalytic activity for hydrogen evolution remains a significant challenge. Herein, we present an efficient approach to enhance the photocatalytic performance of linear conjugated polymers by modifying the surface chemistry via introducing a hydrophilic adenine group into the side chain. The adenine unit with five nitrogen atoms could enhance the interaction between the surface of polymer photocatalyst and water molecules through the formation of hydrogen bonding, which improves the hydrophilicity and dispersity of the resulting polymer photocatalyst in the photocatalytic reaction solution. In addition, the strong electron-donating ability of adenine group with plentiful nitrogen atoms could promote the separation of light-induced electrons and holes. As a result, the adenine-functionalized conjugated polymer PF6A-DBTO2 shows a high photocatalytic activity with a hydrogen evolution rate (HER) of 25.21 mmol g?1 h?1 under UV-Vis light irradiation, which is much higher than that of its counterpart polymer PF6-DBTO2 without the adenine group (6.53 mmol g?1 h?1). More importantly, PF6A-DBTO2 without addition of a Pt co-catalyst also exhibits an impressive HER of 21.93 mmol g?1 h?1 under visible light (λ > 420 nm). This work highlights that it is an efficient strategy to improve the photocatalytic activity of conjugated polymer photocatalysts by the modification of surface chemistry. 相似文献
2.
Harshavardhan Mohan Jeong-Muk Lim Se-Won Lee Min Cho Yool-Jin Park Kamala-Kannan Seralathan Byung-Taek Oh 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2020,95(1):297-307
The cover image is based on the Research Article V2O5/RGO/Pt nanocomposite on oxytetracycline degradation and pharmaceutical effluent detoxification by Mohan, H et al., DOI: 10.1002/jctb.6238 .
3.
Sammar Minallah Erum Pervaiz M. Usman Yousaf M. Bilal Khan Niazi Liu Honghong 《分离科学与技术》2020,55(15):2623-2641
ABSTRACT Current health situations have instigated increased frequency of taking antibiotics for cure of infections but this amplified use is posing threats to environment. This research is focused to remove Tetracycline (TC), an antibiotic from water, using an advanced nanohybrid that compact the properties of adsorbent and photocatalyst. Compared to conventional methods for remediation of TC, large surface area (452 m2g?1) adsorbent photocatalyst hybrid (APH) g-C3N4/α-MoO3/ZIF-67 (CMZ) have found much effective as 97% degradation of TC is observed in 110 min with 0.1 g of APH. Increasing g-C3N4 in the hybrids has improved percent degradation of TC molecules. CMZ-3 is found as a potential candidate for water treatment. 相似文献
4.
This paper reports for the first time, synthesis of NiCo2O4 nano spinel by green oxidative precipitation and its performance in photocatalytic desulfurization of dibenzothiophene (DBT) from gas oil model at different process conditions under visible light. The as-produced nanostructure was characterized by X-ray diffraction, Fourier transform infrared, UV–VIS diffuse reflective spectroscopy, energy-dispersive X-ray spectrometry and scanning electron microscopy. The experiments for the study of different photocatalytic conditions were designed by response surface methodology and a second-order regression model was developed with a determination coefficient (R2) of 0.9769. Pareto analysis predicted that the relative importance of process factors for DBT removal is as follows: irradiation time?>?reaction temperature?>?photocatalyst dosage?>?DBT concentration. The promising results for DBT removal were concluded by photo desulfurization over the nano spinel. The study confirmed that nano spinels could be an alternative and cheap photocatalyst for desulfurization from the oil products. 相似文献
5.
CNT/g‐C3N4 photocatalysts with enhanced hydrogen evolution ability for water splitting based on a noncovalent interaction 下载免费PDF全文
Graphite carbon nitride (g‐C3N4) as a novel photocatalyst has attracted growing attention, but its photocatalytic efficiency should be further improved. Based on the large work function and fast electron conductivity of carbon nanotubes (CNTs), here CNT/g‐C3N4 photocatalysts with improved H2 evolution ability and stable water splitting ability were synthesized. The improvement was attributed to the synergistic effect between CNTs and g‐C3N4. As for the mechanisms, CNTs strongly attracted photoelectrons and, because of excellent conductibility, rapidly transferred photoelectrons from the catalyst interface. Thereby, the photoelectron migration rate and the photogenerated charge separation and the use efficiency of photoelectrons in g‐C3N4 were improved, which largely enhanced the hydrogen production ability. Moreover, the addition of CNTs improved the service life and stability of g‐C3N4‐based photocatalytic H2 production. After 10 hours of visible light irradiation, the maximum H2 yield from the 12‐mg/L CNT/g‐C3N4 (CG12) was 138.7 times larger than that of g‐C3N4 (6548.4 vs 47.2 μmol/g), and the H2 evolution rate was 138.7 times that of g‐C3N4 (654.8 vs 4.72 μmol/g/h). After 50 hours, the apparent quantum efficiency of CG12 was up to 37.9%, indicating that the addition of CNTs improved the photocatalytic splitting and stability of g‐C3N4. The mechanism of photocatalytic hydrogen production and the roles of CNTs in improving water splitting were discussed through characterization and activity experiments. It was found that the addition of CNTs accelerated the migration, separation, and utilization of photoelectrons and thereby significantly enhanced the photocatalytic performance. 相似文献
6.
Fahad A. Alharthi G. Nagaraju S P Vinay Udayabhanu Nabil Al-Zaqri Ali Alsalme 《国际能源研究杂志》2020,44(11):8362-8371
The photocatalytic hydrogen generation is a novel, eco-friendly and favourable method for production of green and clean energy using light energy. In this direction, we report low-temperature ionothermal method for the preparation of TiO2 nanoparticles (NPs) using methoxy ethyl methyl imidazolium tris (pentafluoroethyl) trifluoro phosphate (MOEMINtf2) as an ionic liquid (IL) at 120°C for 1 day. The synthesized nanomaterials were examined using different spectrochemical methods like UV-DRS, XRD, FT-IR, TEM, BET and TGA-DTA techniques. The mixed phase TiO2 is obtained with 81.7% of anatase and 18.3% of rutile phase by the XRD studies, and average crystallite size is found to be ∼7 nm. The stretching of Ti-O bond (∼555 cm−1) and few other bands related to ionic liquid were confirmed by FTIR spectrum. The band gap energy was observed to be ∼3.38 eV by UV-DRS analysis. TEM images reveal spherical shape with an average particles size of about 10 nm. Photocatalytic H2 generation was carried out using TiO2 NPs and observed the generation of 553 μmol h−1 g−1 via water splitting reaction. Furthermore, the prepared TiO2 NPs employed for the photocatalytic degradation of methylene blue dye (84.54%), and photoluminescence studies confirms the obtained material can be used in optoelectronic applications with green emission. 相似文献
7.
《International Journal of Hydrogen Energy》2020,45(53):28437-28446
Exploiting efficient and stable noble metal-free hydrogen evolution catalysts for water splitting is of great importance. In this work, NixCo1-xO@C/CdS hybrid is successfully fabricated through an electrostatic interaction of oppositely charged nanoparticles on their surfaces. The resulting NixCo1-xO@C nanoboxes cocatalysts which were derived from NiCo-LDH@ZIF-67 with Ni–Co layered double hydroxides (LDH) decorated with ZIF-67 precursor exhibited improved hydrogen production rate compared with bare CdS semiconductor from 0.7 mmol g−1 h−1 to 56 mmol g−1 h−1. It is demonstrated that the electrostatic interaction between the two surface charged nanoparticles of NixCo1-xO@C and CdS play an important role in migrating and separating of photogenerated charge carriers. The synthesized NixCo1-xO@C as excellent candidates for cost-effective cocatalysts is aimed to substitute for noble metals in photocatalytic H2 evolution. 相似文献
8.
In this paper, under the control strategy of surface charge of BiOCl photocatalyst and the electrostatic adsorption of anions and cations in potassium bromide (KBr) and polyvinylpyrrolidone (PVP), the self-assembly of “walnut-like” BiOCl/Br solid solution nanophotocatalyst at a lower temperature water bath was proposed for the first time. X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive system (EDS), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), UV-Vis, photoluminescence spectroscopy (PL) and Mott-Schottky curve, transient photocurrent densities, and electrochemical impedance spectroscopy (EIS) were used to analyze the properties of materials, including its morphology, element distribution and chemical states, specific surface area, electrochemical property, and photogenic charge transfer. Based on the degradation performance of RhB dye wastewater and phenol in visible and ultraviolet light, and the band structure of BiOCl/Br solid solution, the reason for the improved photocatalytic activity was deeply discussed, and the possible degradation mechanism was also put forward. The above results show that Br− can be inserted into the crystal lattice of BiOCl under the effect of electrostatic adsorption to form solid solution by the interaction between atomic orbitals, which not only reduces the bandgap width but also improves the separation and mobility of photogenic electrons and holes, causing the absorbed light to shift red to the visible region. In addition, when the nBr−/nCl− = 0.67, “walnut-like” BiOCl/Br solid solution was formed, and this kind of special core-shell structure not only can increase the specific surface area, increase the number of active sites, but also can make the light reflect and refract many times in the cavity and further increase the utilization rate of light energy, and then the best photocatalytic activity was achieved. This study provides an new method to enhance the photocatalytic performance of BiOCl and be conducive to the development of modern material science. 相似文献
9.
《Advanced Powder Technology》2020,31(8):3582-3596
BiOBr and BiOCl were decorated on TiO2 QDs through n-p-p heterojunctions by a simple strategy and they were applied for degradation of three organic dyes upon visible illumination. The obtained photocatalysts were analyzed via XRD, FESEM, EDX, UV–vis DRS, PL, BET, TEM, HRTEM, FT-IR, EIS, XPS, and transient photocurrent measurements. The TiO2 QDs/BiOBr/BiOCl nanocomposite with 20% wt. of BiOBr and 30% wt. of BiOCl displayed superior photoability in the degradation of methylene blue, rhodamine B, and fuchsine, which was almost 34.5, 176, and 78.7-times larger than TiO2 and 27.8, 13.5, and 51.5-folds greater than TiO2 QDs, respectively. The results show that the construction of intimate n-p-p heterojunctions between BiOBr, TiO2 QDs, and BiOCl counterparts leads to enhanced visible-light harvesting and improved charge separation, resulted efficiently increased photocatalytic activity. The trapping results proved that h+, •O2−, and OH• species have considerable effects on the degradation reaction. We think that the improved efficiency of the ternary TiO2 QDS/BiOBr/BiOCl photocatalyst is a splendid alternative for the removal of toxic contaminants from wastewater. 相似文献
10.