Sonochemical Treatment Research Articles

Ultrasound/Chlorine: A Novel Synergistic Sono-Hybrid Process for Allura Red AC Degradation

Herein, we present an original report on chlorine activation by ultrasound (US: 600 kHz, 120 W) for intensifying the sonochemical treatment of hazardous organic materials. The coupling of US/chlorine produced synergy via the involvement of reactive chlorine species (RCSs: Cl•, ClO• and Cl2•−), resulting from the sono-activation of chlorine. The degradation of Allura Red AC (ARAC) textile dye, as a contaminant model, was drastically improved by the US/chlorine process as compared to the separated techniques. A synergy index of 1.74 was obtained by the US/chlorine process for the degradation of ARAC (C0 = 5 mg·L−1) at pH 5.5 and [chlorine]0 = 250 mM. The synergistic index increased by up to 2.2 when chlorine concentration was 300 µM. Additionally, the synergetic effect was only obtained at pH 4–6, where HOCl is the sole chlorine species. Additionally, the effect of combining US and chlorine for ARAC degradation was additive for the argon atmosphere, synergistic for air and negative for N2. An air atmosphere could provide the best synergy as it generates a relatively moderate concentration of reactive species as compared to argon, which marginalizes radical–radical reactions compared to radical–organic ones. Finally, the US/chlorine process was more synergistic for low pollutant concentrations (C0 ≤ 10 mg·L−1); the coupling effect was additive for moderate concentrations (C0~20–30 mg·L−1) and negative for higher C0 (>30 mg·L−1). Consequently, the US/chlorine process was efficiently operable under typical water treatment conditions, although complete by-product analysis and toxicity assessment may still be necessary to establish process viability.

A comprehensive review on green perspectives of electrocoagulation integrated with advanced processes for effective pollutants removal from water environment

The rapidly expanding global energy demand is forcing a release of regulated pollutants into water that is threatening human health. Among various wastewater remediating processes, electrocoagulation (EC) has scored a monumental success over conventional processes because it combines coagulation, sedimentation, floatation and electrochemical oxidation processes that can effectively decimate numerous stubborn pollutants. The EC processes have gained some attention through various academic and industrial publications, however critical evaluation of EC processes, choices of EC processes for various pollutants, process parameters, mechanisms, commercial EC technologies and performance enhancement via other degradation processes (DPs) integration have not been comprehensively covered to date. Therefore, the major objective of this paper is to provide a comprehensive review of 20 years of literature covering EC fundamentals, key process factors for a reactor design, process implementation, current challenges and performance enhancement by coupling EC with pivotal pollutant DPs including, electro/photo-Fenton (E/P–F), photocatalysis, sono-chemical treatment, ozonation, indirect electrochemical/advanced oxidation (AO), and biosorption that have substantially reduced metals, pathogens, toxic compound BOD, COD, colors in wastewater. The results suggest that the optimum treatment time, current density, pulse frequency, shaking speed and spaced electrode improve the pollutants removal efficiency. An elegant process design can prevent electrode passivation which is a critical limitation of EC technology. EC coupling (up or downstream) with other DPs has resulted in the removal of organic pollutants and heavy metals with a 20% improved efficiency by EC-EF, removal of 85.5% suspended solid, 76.2% turbidity, 88.9% BOD, 79.7% COD and 93% color by EC-electroflotation, 100% decolorization by EC-electrochemical-AO, reduction of 78% COD, 81% BOD, 97% color by EC-ozonation and removal of 94% ammonia, 94% BOD, 95% turbidity, >98% phosphorus by aerated EC and peroxicoagulation. The major wastewater purification achievements, future potential and challenges are described to model the future EC integrated systems.

Sonochemical Treatment of Oil-Contaminated Wastewater

Sonochemical Treatment of Oil-Contaminated Wastewater

Nanoarchitectured nickel phosphate integrated with graphene oxide for the toxicant diphenylamine detection in food samples

To date, numerous chemical substances are existing in food products, which cause some health issues in humans. Monitoring and controlling the level of toxicity in food for daily life is an important one. Hence, rapid and inexpensive detection methods are developed for the quantification of toxic chemicals. As a consequence, we have chosen the electrochemical sensing method for the detection of food toxicant diphenylamine (DPA). Herein, the flake-like structured nickel phosphate (NPO) is synthesized using the coprecipitation method and the preparation of NPO integrated graphene oxide (GO) by sonochemical treatment. As observed from electrochemical impedance spectra (EIS) analysis, the NPO/GO modified screen-printed carbon electrode (SPCE) has a lower charge transfer resistance (Rct) of 624 Ω and a fast electron transfer rate. The higher catalytic activity of NPO combined with a higher conductive and active surface area of GO through the electrostatic interaction is applied for the electrochemical determination of DPA. Using the differential pulse voltammetry (DPV) technique, the constructed NPO/GO/SPCE has a broad linear range (0.4 −680.8 μM), low LOD (12 nM), and good sensitivity (1.01 µA µM–1 cm–2) towards DPA sensing. Furthermore, the resultant sensor revealed good selectivity, cyclic and storage stability, repeatability, and reproducibility. The practical application of the DPA was estimated in food samples such as apple, grapes, and orange juice with satisfactory recovery.

Morphological, UV blocking, and antimicrobial features of multifunctional cotton fibers coated with ZnO/Cu via sonochemistry

Multifunctional textiles have been quoted as a technologically and economically viable alternative to prevent the contamination and proliferation of microorganisms, increasing biomedical devices' safety by combining different properties with antimicrobial activities. The present work applied ultrasound waves to coat cotton fibers with ZnO and copper nanoparticles, using citric acid as an eco-friendly reductant/binder agent with different concentrations. We evaluated the cellulose morphology change caused by the surface treatment and the modification impact on different properties of cotton fibers using X-ray Diffractometry (XRD), Fourier-Transform Raman Spectroscopy (FT-Raman), colorimetry, Scanning Electron Microscopy (SEM), agar diffusion tests, and uniaxial tensile tests. The surface functionalization caused significant changes in the properties of the cotton fibers, including the relative proportions of cellulose Iβ and II, present in the cotton fibers, as demonstrated by the Rietveld refinement using X-ray diffractogram data. The multifunctional fibers are effective against Escherichia coli under photoirradiation, indicating that ROS generation is the most responsible mechanism for the bactericidal properties of the fibers. The sonochemical treatment present here is suitable for developing fabrics with multiple functional capacities, such as antimicrobial properties and UV blocking, using renewable sources.

Insights into ultrasound-promoted degradation of naphthenic acid compounds in oil sands process affected water. Part II: In silico quantum screening of hydroxyl radical initiated and propagated degradation of benzoic acid

In Part I, we outlined the importance of sustainable sonochemical treatment to intensify oil sands process affected water (OSPW) treatment empirically and hypothesized degradation pathways. Herein, we elucidate the formation of intermediate products with well-defined molecular level solutions. Proposed mechanisms describe hydroxylation, decarboxylation and bond scission which drive the degradation of intermediates towards mineralization. This comprehensive first study on in silico screening of sonochemical degradation investigates quantum methods using density functional theory to explain the postulated degradation mechanisms through a theoretical radical attack approach, based on condensed Fukui reactivity indicators. A nudged elasticity band (NEB) approach is applied to find a minimum energy path (MEP), allowing the determination of intermediate products and energy barriers associated with naphthenic acid degradation. This approach provides structures and energies of the breakdown compounds formed along the reaction pathway enabling the determination of molecular reaction kinetics.In continuation of Part 1, the focus of this study is to evaluate sonochemically-induced hydroxyl radical (OH•) reactions of benzoic acid using density functional theory. Hydroxylation and decarboxylation mechanisms of the model naphthenic acid compound and its intermediates were simulated to determine the prospective pathway to ideal mineralization. DFT was applied to calculate interaction energies, Mulliken charges, Hirshfeld population analysis, dipole moments, frontier orbitals, and polarizability. Electronic properties and frontier orbital trends were also compared to computational work by Riahi et al.[1] to confirm the transition states by Nudged Elastic Band Transition State theory (NEB-TS). In combination with Hirshfeld Population analysis, Fukui indices suggest a more linear degradation pathway narrowed down from earlier experimental work by Singla et al.[2]. The linear free energy relationship for the newly suggested computational benzoic acid degradation can be determined by lnkTST/W=-1.677ΔG-15.41 with a R2 of 0.9997 according to classic transition state theory and Wigner tunneling. This computational method can be used to explore possible degradation pathways of other NAs and bridges molecular-to-macroscale sonochemical degradation of NA’s through a manifestation of molecular solutions.

Preparation and characterization of layered-double hydroxides decorated on graphene oxide for dye removal from aqueous solution

In this study, coprecipitation method followed by sonochemical treatment was used to prepare layered-double hydroxides (LDH) and graphene oxide-layered-double hydroxides (GO-LDH). GO-LDH and LDH adsorption performance were evaluated using aqueous solution of Methyl Orange dye (MO). The LDH and GO-LDH were characterized using various advanced techniques. The analysis of data collected from the XRD pattern and size distribution showed that the presence of GO will increase the inter-space between the LDH layers and the polydispersity index than pure LDH. This will make the ion exchange be easier and improve the adsorption process. The adsorption kinetic studies presented that the adsorption of MO dye on LDH and GO-LDH follows a pseudo-second-order reaction. Moreover, according to intraparticle diffusion, GO-LDH has a faster diffusion constant for MO molecules than LDH. Furthermore, as predicted by Langmuir, the maximum adsorption ability of MO using GO-LDH (505.1 mgg−1) which was higher than LDH (400 mgg−1). Finally, LDH and GO-LDH were successfully regenerated using 1.0 M NaOH and Methanol, respectively. Moreover, the GO-LDH showed excellent reusability behavior compared to LDH. This suggests that GO-LDH could be a costless adsorbent compared to LDH.

Co3O4@chitosan/La2O3 nanocomposites as innovative, powerful, and recyclable nanocatalysts for sonochemical treatment of benzyl alcohols to obtain the corresponding benzaldehyde derivatives.

Ultrasonic (US) irradiation (100 W, 40 kHz) reactions, used as a safe and green technique, are often more efficient than traditional protocols. This leads us to introduce, for the first time, an efficient nanocatalyst and immobilization of La2O3 nanoparticles on Co3O4 nanoparticles for the selective oxidation of benzyl alcohol to the corresponding benzaldehyde at room temperature. The structural and morphological characteristics of the nanocatalysts were determined by FT-IR, XRD, FE-SEM, EDX, and VSM. The catalytic performance of the Co3O4@Cs/La2O3 composites used as heterogeneous nanocatalysts was investigated in the selective oxidation of benzylic alcohols to their corresponding benzaldehydes. Also, the performance of the oxidation parameters, including H2O2 concentration, time, effect of various solvents, and nanocatalyst dosage was checked. Significant benefits of this method can be named by using a non-toxic solvent, easy product isolation, excellent recoverability, low time of reaction, high yield, and ultrasound irradiation. Finally, a possible mechanism was proposed to show the nanocatalytic process.

Topological Data Analysis of Nanoscale Roughness in Brass Samples.

Rough surfaces possess complex topographies, which cannot be characterized by a single parameter. The selection of appropriate roughness parameters depends on a particular application. Large datasets representing surface topography possess orderliness, which can be expressed in terms of topological features in high-dimensional dataspaces reflecting properties such as anisotropy and the number of lay directions. The features are scale-dependent because both sampling length and resolution affect them. We study nanoscale surface roughness using 3 × 3, 4 × 4, and 5 × 5 pixel patches obtained from atomic force microscopy (AFM) images of brass (Cu Zn alloy) samples roughened by a sonochemical treatment. We calculate roughness parameters, correlation length, extremum point distribution, persistence diagrams, and barcodes. These parameters of interest are discussed and compared.

Electrochemical deposition of tin-copper alloy coatings

Solderable tin-base alloy coatings are widely used when assembling electronic products. The reorientation of production to lead-free technologies sets the task of developing new technological processes for the formation of coatings for electrical contacts with stable electrical properties, high soldering ability, which lasts for a long time. The features of the process of electrodeposition of coatings with a tin-copper alloy were experimentally investigated and the regularities of the influence of the electrolyte composition, current density, and ultrasound intensity on the cathode current efficiency of the alloy, the deposition rate, elemental composition, structure and functional properties of the precipitation were established. For sonochemical treatment an experimental setup developed at Research Laboratory 5.2 of BSUIR, which makes it possible to vary the intensity of ultrasonic vibrations in the range of 0.058– 1.7 W/cm2 , was used. It has been established that the use of ultrasound changes the formation mechanism of the electrochemical alloy, reduces cathodic polarization, increases the value of the limiting current and makes it possible to control the composition and structure of the precipitates. With an increase in the intensity from 0.12 to 0.95 W/cm2 the amount of copper in the coating increases by 4.5 times. The spreading coefficient of the solder is 92.59–98.44 %.

Mesoporous onion-like carbon nanostructures from natural oil for high-performance supercapacitor and electrochemical sensing applications: Insights into the post-synthesis sonochemical treatment on the electrochemical performance

Although onion-like carbon nanostructures (OLCs) are attractive materials for energy storage, their commercialization is hampered by the absence of a simple, cost-effective, large-scale synthesis route and binder-free electrode processing. The present study employs a scalable and straightforward technique to fabricate sonochemically tailored OLCs-based high-performance supercapacitor electrode material. An enhanced supercapacitive performance was demonstrated by the OLCs when sonicated in DMF at 60 °C for 15 min, with a specific capacitance of 647 F/g, capacitance retention of 97% for 5000 cycles, and a charge transfer resistance of 3 Ω. Furthermore, the OLCs were employed in the electrochemical quantification of methylene blue, a potential COVID-19 drug. The sensor demonstrated excellent analytical characteristics, including a linear range of 100 pM to 1000 pM, an ultralow sensitivity of 64.23 pM, and a high selectivity. When used to identify and quantify methylene blue in its pharmaceutical formulation, the sensor demonstrated excellent reproducibility, high stability, and satisfactory recovery.

Multiple response optimization of ultrasound-assisted procedure for multi-element determination in Brazilian wine samples by microwave-induced plasma optical emission spectrometry

In the present work, a method was developed, optimized, and validated for the determination of aluminum, manganese, lead, copper, cadmium, and zinc by microwave-induced plasma optical emission spectrometry of wine samples from the São Francisco Valley, northeastern Brazil. The samples were subjected to a sonochemical treatment aiming at the degradation of the sample matrix. To optimize the analytical procedure, initially, a two-level fractional factorial design was used to study five experimental variables and determine which ones significantly affected the analytical response. In a second step, the significant variables were optimized using the Doehlert matrix as the response surface methodology and the desirability function as a strategy to optimize multiple responses. The optimum conditions established were concentrations of nitric acid (2.3 mol L−1) and hydrogen peroxide (9%). The developed method is simple, fast, and precise, has a low operational cost and low limits of detection and quantification. The accuracy confirmed by spike tests with recoveries ranging from 104 to 118% and comparative analysis of the results obtained using the proposed method and digestion total procedure. The method was applied for multi-element determination in three wine samples.

Effect of Sonochemical Treatment on Thermal Stability, Elemental Mercury (Hg0) Removal, and Regenerable Performance of Magnetic Tea Biochar.

Elemental mercury (Hg0) removal from a hot gas is still challenging since high temperature influences the Hg0 removal and regenerable performance of the sorbent. In this work, a facile yet innovative sonochemical method was developed to synthesize a thermally stable magnetic tea biochar to capture the Hg0 from syngas. A sonochemically synthesized magnetic sorbent (TUF0.46) exhibited a more prodigious surface area with developed pore structures, ultra-paramagnetic properties, and high dispersion of Fe3O4/γ-Fe2O3 particles than a simply synthesized magnetic sorbent (TF0.46). The results showed that TUF0.46 demonstrated strong thermostability and attained a high Hg0 removal performance (∼98.6%) at 200 °C. After the 10th adsorption/regeneration cycle, the Hg0 removal efficiency of TUF0.46 was 19% higher than that of TF0.46. Besides, at 23.1% Hg0 breakthrough, TUF0.46 achieved an average Hg0 adsorption capacity of 16.58 mg/g within 24 h under complex syngas (20% CO, 20% H2, 5% H2O, and 400 ppm H2S). In addition, XPS results revealed that surface-active components (Fe+, O2–, O*, C=O) were the key factor for high Hg0 removal performance over TUF0.46 from syngas. Hence, sonochemistry is a promising practical tool for improving the surface morphology, thermal resistance, renewability, and Hg0 removal efficiency of a sorbent.

Facile synthesis of alpha-phase strontium pyrophosphate incorporated with polypyrrole composite for the electrochemical detection of antipsychotic drug chlorpromazine

The ceramic material alpha-phase strontium pyrophosphate (α-Sr2P2O7, SPO) was synthesized via the coprecipitation technique and the polypyrrole (PPy) was prepared through the chemical oxidation technique. The SPO incorporated with PPy composite was prepared using the sonochemical treatment which is applied for the electrochemical oxidation of antipsychotic drug chlorpromazine (CPZ). The SPO/PPy is engineered through electrostatic interaction of positively charged PPy and negatively charged SPO. This specific property enhances the conductivity and catalytic activity of the modified electrode. The resultant SPO/PPy was examined using various characterization techniques and the electrochemical activity of SPO/PPy modified screen-printed carbon electrode (SPCE) was assessed through electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) methods. The constructed SPO/PPy/SPCE has broad linearity of 0.8–1207 µM with the lowest detection limit (LOD) of 0.069 µM, and a sensitivity of 0.592 µA µM–1 cm–2 towards the detection of CPZ. Further, the CPZ sensor revealed good specificity, cyclic stability, and precision. The real-time monitoring of CPZ was estimated in human urine and serum samples with good recoveries.

Development of magnetic, ferrite supported palladium catalysts for 2,4-dinitrotoluene hydrogenation

Cobalt, copper, and nickel ferrite spinel nanoparticles have been synthesized by using a combination of sonochemical treatment and combustion. The magnetic nanoparticles have been used as supports to prepare ~4 wt% palladium catalysts. The ferrites were dispersed in an ethanolic solution of Pd(II) nitrate by ultrasonication. The palladium ions were reduced to metallic Pd nanoparticles, which were then attached to the surface of the different metal oxide supports. Thus, three different catalysts (Pd/CoFe2O4, Pd/CuFe2O4, Pd/NiFe2O4) were made and tested in the hydrogenation of 2,4-dinitrotoluene (DNT). A possible reaction mechanism, including the detected species, has been envisaged based on the results. The highest 2,4-diaminotoluene (TDA) yield (99 n/n%) has been achieved by using the Pd/NiFe2O4 catalyst. Furthermore, the TDA yield was also reasonable (84.2 n/n%) when the Pd/CoFe2O4 catalyst was used. In this case, complete and easy recovery of the catalyst from the reaction medium is ensured, as the ferrite support is fully magnetic. Thus, the catalyst is very well suited for applicationy in the hydrogenation of DNT or other aromatic nitro compounds.

Circular motion of submillimeter-sized acoustic bubbles attached to a boundary by high-speed image analysis

The circular motion of submillimeter-sized bubbles attached to a boundary in an 18.5 kHz ultrasonic field are investigated experimentally by high-speed photography and image analysis. It is found that the vibration of gas bubbles with diameters of 0.2–0.4 mm is between spherical radial vibration and regular surface fluctuation. Different from the circular motion of suspended bubbles in water, the circular motion of gas bubbles attached to a boundary presents some new characteristics. These bubbles attached to a boundary (wandering bubbles) will rotate around a fixed bubble array (holding bubbles). Both the wondering bubbles and holding bubbles are “degas” bubbles. The primary Bjerknes force acting on wandering bubbles in the acoustic wave field and the secondary Bjerknes force between the wandering bubbles and the holding bubbles strongly affects the circular motion. The circling and residence behavior of gas bubbles is described and analyzed in detail, which is helpful to understand and improve industrial applications such as ultrasonic cleaning, sonochemical treatment, aeration and cavitation reduction.

Understanding the effects of mineral water matrix on degradation of several pharmaceuticals by ultrasound: Influence of chemical structure and concentration of the pollutants

Degradation of seven relevant pharmaceuticals with different chemical structures and properties: acetaminophen (ACE), cloxacillin (CXL), diclofenac (DCF), naproxen (NPX), piroxicam (PXC), sulfacetamide (SAM) and cefadroxil (CDX), in distilled water and mineral water by ultrasound was studied herein. Firstly, proper conditions of frequency and acoustic power were determined based on the degradation ability of the system and the accumulation of sonogenerated hydrogen peroxide (24.4 W and 375 kHz were found as the suitable conditions for the sonochemical treatment of the pharmaceuticals). Under such conditions, the pharmaceuticals degradation order in distilled water was: PXC > DCF ~ NPX > CXL > ACE > SAM > CDX. In fact, the initial degradation rate showed a good correlation with the Log P parameter, most hydrophobic compounds were eliminated faster than the hydrophilic ones. Interestingly, in mineral water, the degradation of those hydrophilic compounds (i.e., ACE, SAM and CDX) was accelerated, which was attributed to the presence of bicarbonate ions. Afterwards, mineral water containing six different initial concentrations (i.e., 0.331, 0.662, 3.31, 16.55, 33.1, and 331 µM) of selected pharmaceuticals was sonicated, the lowest concentration (0.331 µM) always gave the highest degradation of the pollutants. This result highlights the great ability of the sonochemical process to treat bicarbonate-rich waters containing pollutants at trace levels, as pharmaceuticals. Finally, the addition of ferrous ions to the sonochemical system to generate a sono-Fenton process resulted in an acceleration of degradation in distilled water but not in mineral water. This was attributed to the scavenging of sonogenerated HO• by bicarbonate anion, which decreases H2O2 accumulation, thus limiting the Fenton reaction.

An innovative green approach to the production of bio-sourced and nano-sized graphene oxide (GO)-like carbon flakes

In this study, we developed a green and facile top–down approach for the production of nano-sized graphene oxide (GO) like flakes from natural sources by sonochemistry. The long carbon flakes produced by the pyrolysis of waste onion sheathing were then converted into uniform nano-sized GO-like flakes (6.6 ​± ​2.4 ​nm) by sonication in deionized water. The effect of time on the size of GO-like nanostructures obtained by ultrasonication of bio-sourced carbon flakes has been extensively investigated. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to determine the size of these nanostructures. The changes in the surface chemical composition of the nanostructures during the sonochemical treatment were analyzed by X-ray photoelectron spectroscopy (XPS). Furthermore, cytotoxicity and hemocompatibility of nano-sized GO-like flakes were evaluated. Pyrolysis of waste onion sheathing followed by sonication could therefore be explored as a highly cost-effective, eco-friendly, uncomplicated, green, and efficient way of producing large-scale nano-sized GO-like carbon flakes.

Degradation of Losartan in Fresh Urine by Sonochemical and Photochemical Advanced Oxidation Processes

In this work, the degradation of the pharmaceutical losartan, in simulated fresh urine (which was considered because urine is the main excretion route for this compound) by sonochemistry and UVC/H2O2 individually, was studied. Initially, special attention was paid to the degrading action of the processes. Then, theoretical analyses on Fukui function indices, to determine electron-rich regions on the pharmaceutical susceptible to attacks by the hydroxyl radical, were performed. Afterward, the ability of the processes to mineralize losartan and remove the phyto-toxicity was tested. It was found that in the sonochemical treatment, hydroxyl radicals played the main degrading role. In turn, in UVC/H2O2, both the light and hydroxyl radical eliminated the target contaminant. The sonochemical system showed the lowest interference for the elimination of losartan in the fresh urine. It was established that atoms in the imidazole of the contaminant were the moieties most prone to primary transformations by radicals. This was coincident with the initial degradation products coming from the processes action. Although both processes exhibited low mineralizing ability toward losartan, the sonochemical treatment converted losartan into nonphytotoxic products. This research presents relevant results on the elimination of a representative pharmaceutical in fresh urine by two advanced oxidation processes.

Ultrasonically prepared photocatalyst of W/WO3 nanoplates with WS2 nanosheets as 2D material for improving photoelectrochemical water splitting

A sonochemical treatment has been an emerged technique as an interesting method for fabricating different photocatalysts with unique photoelectrochemical (PEC) properties. This study investigated the PEC performance of WO3 with WS2 nanosheets as a 2D material before calcination (WO3/WS2-90) and after calcination (WO3/WS2-450) prepared with sonochemical treatment. The WS2 nanosheets were prepared from a liquid exfoliation phase with few-layer nanosheets, approximately 6.5 nm in thickness. The nanosheets were confirmed by UV–Vis spectroscopy and atomic force microscopy. Further, XPS, RAMAN, and SEM-EDAX analyses indicated that, following calcination of the WO3/WS2 electrode, the WS2 nanosheets initially transformed to 2D-WO3. After depositing the WS2 nanosheets on the WO3, the photocurrent density increased substantially. The WO3/WS2-450 films after calcination showed a photocurrent density of 5.6 mA.cm−2 at 1.23 V vs. Ag/AgCl, which was 3.1 and 7.2 times higher, respectively than those of the WO3/WS2-90 before calcination and pure WO3. Mott-Schottky and electrochemical impedance spectroscopy analyses confirmed the fabrication of the WO3/WS2 photoanode after calcination. The deposition of WS2 nanosheets onto pure WO3 increased the donor concentration (24-fold), reduced the space charge layer (4.6-fold), and decreased the flat band potential (1.6-fold), which could all help improve the photoelectrochemical efficiency. Moreover, the incorporation of WO3 with WS2 nanosheets as a 2D material (WO3/WS2-450) enhanced the incident photon current efficiency (IPCE) by 55%. In addition, the applied-bias photon-to-current conversion efficiency of the WO3/WS2-450 films was approximately 2.26% at 0.75 V (vs. Ag/AgCl), which is 5.6 and 9 times higher, respectively than those of WO3/WS2-90 and pure WO3.