S-scheme heterojunction Bi2O3-ZnO/Bentonite clay composite with enhanced photocatalytic performance

Landge, Vividha K.; Sonawane, Shirish H.; Sivakumar, M.; Sonawane, Shriram S.; Babu, G. Uday Bhaskar; Boczkaj, Grzegorz

doi:10.1016/j.seta.2021.101194

Cited by 46 publications

(29 citation statements)

References 41 publications

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“…The long-life charge carriers assured the composites of better H2O2 production performance. We also compared the transient photocurrent responses and electrochemical impedance spectra (EIS) of the samples 59,63 . The ZP2 composites showed an enhanced photocurrent than pure ZnO or PDA (Fig.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Photocatalytic H2O2 Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

Han¹,

Xu²,

Cheng³

et al. 2022

Acta Physico Chimica Sinica

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Photocatalytic H2O2 production is a sustainable and inexpensive process that requires water and gaseous O2 as raw materials and sunlight as the energy source. However, the slow kinetics of current photocatalysts limits its practical application. ZnO is commonly used as a photocatalytic material in the solar-to-chemical conversion, owing to its high electron mobility, nontoxicity, and relatively low cost. The adsorption capacity of H2O2 on the ZnO surface is low, which leads to the continuous production of H2O2. However, its photoresponse is limited to the ultraviolet (UV) region due to its wide bandgap (3.2 eV). Polydopamine (PDA) has emerged as an effective surface functionalization material in the field of photocatalysis due to its abundant functional groups. PDA can be strongly anchored onto the surface of a semiconducting photocatalyst through covalent and noncovalent bonds. The superior properties of PDA served as a motivation for this study. Herein, we prepare an inverse opal-structured porous PDA-modified ZnO (ZnO@PDA) photocatalyst by in situ self-polymerization of dopamine hydrochloride. The crystal structure, morphology, valency, stability, and energy band structure of photocatalysts are characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), electrochemical impedance spectroscopy (EIS), Mott-Schottky curve (MS), and electron paramagnetic resonance (EPR). The experimental results showed that electrons in PDA are transferred to ZnO upon contact, which results in an electric field at their interface in the direction from PDA to ZnO. The photoexcited electrons in the ZnO conduction bands flow into PDA, driven by the electric field and bent bands, and are recombined with the holes of the highest occupied molecular orbital of PDA, thereby exhibiting an S-scheme charge transfer. This unique S-scheme mechanism ensures effective electron/hole separation and preserves the strong redox ability of used photocarriers. In addition, the inverse opal structure of ZnO@PDA promotes light-harvesting due to the supposed "slow photon" effect, as well as Bragg diffraction and scattering. Moreover, the enhanced surface area provides a high adsorption capacity and increased active sites for photocatalytic reactions. Therefore, the resulting ZnO@PDA (0.03% (atomic fraction) PDA) exhibits the optimal H2O2 production performance (1011.4 μmol•L −1 •h −1 ), which is 4.4 and 8.9 times higher than pristine ZnO and PDA, respectively. The enhanced performance is ascribed to the improved light absorption, efficient charge separation, and strong redox capability of photocarriers in the S-scheme heterojunction. Therefore, this study provides a novel strategy for the design of inorganic/organic S-scheme heterojunctions for efficient photocatalytic H2O2 production.

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Section: Resultsmentioning

confidence: 99%

Enhanced Photocatalytic H2O2 Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

Han¹,

Xu²,

Cheng³

et al. 2022

Acta Physico Chimica Sinica

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“…Bentonite is a highly available smectite-bearing natural material and has significant adsorption properties, either as a single-phase or as an integrated component in composite [21]. Technically, it has significant surface reactivity, ion exchange properties, flexible structure, adsorption capacity, nontoxicity, biocompatibility, and surface area [5,22].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, several studies demonstrated the valuable impact of the integration processes between the bentonite layers and different species of polymers on the physicochemical properties of the structure as an adsorbent [17,22,23]. Among the addressed polymers, polyaniline is a highly recommended polymer that has inexpensive and facile production procedures, in addition to a high surface area, safety, adsorption capacity, and oxidation properties [24,25].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, the integration between bentonite and some metal oxides or metal-based structures was reported as an effective technique to induce the physicochemical properties of bentonite. This included nickel Fe/Mg LDH [21], magnesium ferrite [28], MoS 2 [29], MgFe 2 O 4 [30], ZnO/CuO [31], and Bi 2 O 3 -ZnO [22]. ZnO nanoparticles, in addition to their base materials, have been assessed extensively as effective adsorbents and photocatalysts in the literature [32,33].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis and Characterization of Green ZnO@polynaniline/Bentonite Tripartite Structure (G.Zn@PN/BE) as Adsorbent for As (V) Ions: Integration, Steric, and Energetic Properties

et al. 2022

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A green ZnO@polynaniline/bentonite composite (G.Zn@PN/BE) was synthesized as an enhanced adsorbent for As (V) ions. Its adsorption properties were assessed in comparison with the integrated components of bentonite (BE) and polyaniline/bentonite (PN/BE) composites. The G.Zn@PN/BE composite achieved an As (V) retention capacity (213 mg/g) higher than BE (72.7 mg/g) and PN/BE (119.8 mg/g). The enhanced capacity of G.Zn@PN/BE was studied using classic (Langmuir) and advanced equilibrium (monolayer model of one energy) models. Considering the steric properties, the structure of G.Zn@PN/BE demonstrated a higher density of active sites (Nm = 109.8 (20 °C), 108.9 (30 °C), and 67.8 mg/g (40 °C)) than BE and PN/BE. This declared the effect of the integration process in inducing the retention capacity by increasing the quantities of the active sites. The number of adsorbed As (V) ions per site (1.76 up to 2.13) signifies the retention of two or three ions per site by a multi-ionic mechanism. The adsorption energies (from −3.07 to −3.26 kJ/mol) suggested physical retention mechanisms (hydrogen bonding and dipole bonding forces). The adsorption energy, internal energy, and free enthalpy reflected the exothermic, feasible, and spontaneous nature of the retention process. The structure is of significant As (V) uptake capacity in the existence of competitive anions or metal ions.

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“…The main purpose of altering the morphologies of photocatalyst is to reduce its band gap and increase the light response to the visible zone, as well as the recombination reduction of the electron/hole pair and increase the photocatalytic activity of semiconductors. In an effort to develop effective methods for the removal of lethal contaminants from wastewater and water treatment, the focus is on the development of a binary metal oxide catalyst supported for the photocatalytic oxidation process used in wastewater [136,137]. In this regard, doping with correct choice of the metal ions and its optimum concentration, can be used to change the chemical, physical, optical and photocatalytic properties of raw materials in a complex way [138].…”

Section: Air and Water Purificationmentioning

confidence: 99%

Advances in metal-based vanadate compound photocatalysts: synthesis, properties and applications

Akhoondi

Feleni

Bethi³

et al. 2021

Synth. Sinter.

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Among the ongoing research on photocatalysis under visible-light, it has been shown that doped or hybrid catalysts are more active than a single catalyst alone. However, problems including visible light absorption, a low quantity of energetic sites on surfaces, and rapid recombination of the photo-electron hole pair produced by light have prohibited photocatalysts from being used in a practical and widespread manner. To overcome these problems, synthesis of nanostructure hybrid catalyst using several methods has attracted much attention. Several procedures have been suggested for the preparation of photocatalysts with the desired structure and morphology. Preparation methods similar to partial modification may lead to diverse structures and qualities. In this regard, the development of efficient, low-cost photocatalysts and rapid synthesis is the most important issues that should be considered. This review discusses various methods and mechanisms that work with the modification of vanadium compounds as photocatalysts to progress their photocatalytic efficiency. In addition, the effects of synthesis temperature, solution pH and concentration on the photocatalytic performance are also described in detail.

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S-scheme heterojunction Bi2O3-ZnO/Bentonite clay composite with enhanced photocatalytic performance

Cited by 46 publications

References 41 publications

Enhanced Photocatalytic H<sub>2</sub>O<sub>2</sub> Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

Enhanced Photocatalytic H<sub>2</sub>O<sub>2</sub> Production over Inverse Opal ZnO@ Polydopamine S-scheme Heterojunctions

Synthesis and Characterization of Green ZnO@polynaniline/Bentonite Tripartite Structure (G.Zn@PN/BE) as Adsorbent for As (V) Ions: Integration, Steric, and Energetic Properties

Advances in metal-based vanadate compound photocatalysts: synthesis, properties and applications

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