Abstract:Piezo-photocatalysis, which combines the piezoelectric
and photoresponsive
behavior of materials, is considered a promising strategy for water
treatment. As an established piezomaterial, herein, we report the
photocatalytic, piezocatalytic, and piezo-photocatalytic responses
of bismuth vanadate (BiVO4) nanorods under ultrasonic frequency
(35 kHz) and selected visible light excitation. We used a facile hydrothermal
method to produce BiVO4 nanorods. The as-synthesized (B180)
and calcined (C300, C500, and C700) B… Show more
“…To further confirm the role of O 2 ·– and · OH in photocatalysis, we performed nitro-blue tetrazolium (NBT) and terephthalic acid (TA) tests (Figure S14). , NBT shows a peak intensity at 265 nm. Upon reacting with O 2 ·– , it creates formazon.…”
Defect engineering and hetero-interfacial bending are standard approaches for enhancing carrier separation and increasing visible light absorption in a semiconductor photocatalyst. Here, we demonstrate the evolution of sulfur vacancies (V S ) and the self-assembly of a p−n homojunction through prolonged aqueous washing of SnS 2 nanosheets. The experimental studies have validated increased hydrophilicity, layer thinning, V S generation, and extended photocarrier lifetime in washed SnS 2 nanosheets. Density functional theory has revealed the changes in the local electronic structure of SnS 2 in the presence of structural defects. An electrochemical impedance spectroscopy study has shown that V S actuates the self-assembly of a pseudo-p-type SnS layer over n-type SnS 2 to generate the p−n homojunction. The ptype carrier densities are increased twice as the number of washings is increased from 3 to 10 times. The photocatalytic efficacy of the SnS 2 homojunction is evaluated in the study of the degradation of several water contaminants under white light and monochromatic excitations. The proposed mechanism shows that the built-in electric field at the p−n junction promotes the separation of the photogenerated electrons and holes. Meanwhile, V S traps the electrons and transfers them to the catalytically reactive centers to participate in photocatalysis. Our findings demonstrate that a simple approach that involves prolonged aqueous washing of as-produced SnS 2 promotes the formation of V S and the self-assembly of a p−n homojunction in SnS 2 nanosheets with improved visible light photocatalytic performances.
“…To further confirm the role of O 2 ·– and · OH in photocatalysis, we performed nitro-blue tetrazolium (NBT) and terephthalic acid (TA) tests (Figure S14). , NBT shows a peak intensity at 265 nm. Upon reacting with O 2 ·– , it creates formazon.…”
Defect engineering and hetero-interfacial bending are standard approaches for enhancing carrier separation and increasing visible light absorption in a semiconductor photocatalyst. Here, we demonstrate the evolution of sulfur vacancies (V S ) and the self-assembly of a p−n homojunction through prolonged aqueous washing of SnS 2 nanosheets. The experimental studies have validated increased hydrophilicity, layer thinning, V S generation, and extended photocarrier lifetime in washed SnS 2 nanosheets. Density functional theory has revealed the changes in the local electronic structure of SnS 2 in the presence of structural defects. An electrochemical impedance spectroscopy study has shown that V S actuates the self-assembly of a pseudo-p-type SnS layer over n-type SnS 2 to generate the p−n homojunction. The ptype carrier densities are increased twice as the number of washings is increased from 3 to 10 times. The photocatalytic efficacy of the SnS 2 homojunction is evaluated in the study of the degradation of several water contaminants under white light and monochromatic excitations. The proposed mechanism shows that the built-in electric field at the p−n junction promotes the separation of the photogenerated electrons and holes. Meanwhile, V S traps the electrons and transfers them to the catalytically reactive centers to participate in photocatalysis. Our findings demonstrate that a simple approach that involves prolonged aqueous washing of as-produced SnS 2 promotes the formation of V S and the self-assembly of a p−n homojunction in SnS 2 nanosheets with improved visible light photocatalytic performances.
“…This implied that PVDF/BT40-50 had highly effective and broad-spectrum antibacterial activity. The fast bacteria-killing behavior of the materials and composite membrane was superior to other works [ 47 – 49 ]. However, due to excessive doping of BT40, the antibacterial effect of PVDF/BT40-60 was not further improved (Fig.…”
In this study, an antibacterial nanofiber membrane [polyvinylidene fluoride/Bi
4
Ti
3
O
12
/Ti
3
C
2
T
x
(PVDF/BTO/Ti
3
C
2
T
x
)] is fabricated using an electrostatic spinning process, in which the self-assembled BTO/Ti
3
C
2
T
x
heterojunction is incorporated into the PVDF matrix. Benefiting from the internal electric field induced by the spontaneously ferroelectric polarization of BTO, the photoexcited electrons and holes are driven to move in the opposite direction inside BTO, and the electrons are transferred to Ti
3
C
2
T
x
across the Schottky interface. Thus, directed charge separation and transfer are realized through the cooperation of the two components. The recombination of electron–hole pairs is maximumly inhibited, which notably improves the yield of reactive oxygen species by enhancing photocatalytic activity. Furthermore, the nanofiber membrane with an optimal doping ratio exhibits outstanding visible light absorption and photothermal conversion performance. Ultimately, photothermal effect and ferroelectric polarization enhanced photocatalysis endow the nanofiber membrane with the ability to kill 99.61% ± 0.28%
Staphylococcus aureus
and 99.71% ± 0.16%
Escherichia coli
under 20 min of light irradiation. This study brings new insights into the design of intelligent antibacterial textiles through a ferroelectric polarization strategy.
Graphical Abstract
Supplementary Information
The online version contains supplementary material available at 10.1007/s42765-022-00234-8.
“…The reason for this is that the d2 piezo catalyst has a smaller nanoparticle size compared to the d4 and d5. According to Kim et al 35 , piezoelectricity increases non-linearly with decreasing nanostructure size. Figure 6 ( a ) Effect of microwave pulse during synthesis of catalyst on removal of TP and DBTP, ( b ) effect of microwave time during synthesis of catalyst on removal of TP and DBTP, ( c ) effect of calcination temperature during synthesis of catalyst on removal of TP and DBTP, ( d ) effect of calcination time during synthesis of catalyst on removal of TP and DBTP, ( e ) effect of microwave power during synthesis of catalyst on removal of TP, DBTP, kerosene.…”
In order to advance desulfurization technology, a new method for excellent oxidative desulfurization of fuel at room temperature will be of paramount importance. As a novel desulfurization method, we developed piezo-catalysts that do not require adding any oxidants and can be performed at room temperature. A microwave method was used to prepare CeO2/Ce2O3/NiOx nanocomposites. Model and real fuel desulfurization rates were examined as a function of synthesis parameters, such as microwave power and time, and operation conditions, such as pH and ultrasonic power. The results showed that CeO2/Ce2O3/NiOx nanocomposites demonstrated outstanding piezo-desulfurization at room temperature for both model and real fuels. Furthermore, CeO2/Ce2O3/NiOx nanocomposites exhibited remarkable reusability, maintaining 79% of their piezo-catalytic activity even after 17 repetitions for desulfurization of real fuel. An investigation of the mechanism of sulfur oxidation revealed that superoxide radicals and holes played a major role. Additionally, the kinetic study revealed that sulfur removal by piezo-catalyst follows a second-order reaction kinetic model.
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