Simple Drop-coating Method Research Articles

Superhydrophobic/superoleophilic polyurethane /reduced graphene oxide/ sponge for efficient oil-water separation and photothermal remediation

Due to the rapid development of global industrialization, the frequent occurrence of organic matter leakage and oil leakage accidents has led to increasingly serious environmental pollution. Therefore, this paper has proposed a facile and affordable method for creating oil water separation materials, and successful creating a super hydrophobic/super oleophilic functional porous polyurethane sponge modified by reduced graphene oxide and polydopamine (PDA-rGO-PU). Dopamine undergoes a self-polymerization event that creates polydopamine, which is subsequently coated on a polyurethane framework to create a sponge structure with several active sites. The surface of the modified sponge structure was coated with graphene oxide by a simple drop-coating method, and graphene oxide coated on the surface of polydopamine was reduced to create the superhydrophobic/superoleophilic material. The PDA-rGO-PU demonstrated strong anti-adhesion properties and a high oil-water separation efficiency of 99.8 % while having high water contact angles of 155 ° ± 3 ° and oil contact angles (OCA) of 0 °. It has a strong ability to adsorb various oils and organic solvents, the excellent photothermal effect allows PDA-rGO-PU to raise temperature by 37.9 % in the presence of light. PDA-rGO-PU has good continuous oil sorption performance after installing the pump. When under simulated lighting conditions, the sorption time of modified sponge on crude oil was shortened by 2.3 times.

Enhancing the performance of self-powered heterojunctional ZnO/Cs3Bi2I9 photodetectors through pyroelectric-photovoltaic coupling effect

Bismuth (Bi)-based perovskites are promising materials for near-ultraviolet-to-visible light (NUV–vis) detection. However, their practical application has been limited by relatively weak responsivity and detectivity. In this study, we developed a large-area, low-cost, environmentally friendly self-powered NUV–vis photodetector based on a ZnO/Cs3Bi2I9 heterojunction through a simple drop-coating method. Leveraging the pyroelectric effect, the device demonstrates a high responsivity of 10.48 mA/W, specific detectivity of 7.69 × 1010 Jones, and a fast rise time of 0.9 ms. Moreover, we elucidated the physical mechanism of the self-powered NUV–vis photodetector and systematically analyzed the influence of light power density on photoresponse and response time. This study introduces an effective strategy to enhance the performance of Bi-based perovskite photodetectors under zero voltage bias, leveraging the pyroelectric effect induced in ZnO under ultraviolet illumination and the photovoltaic effect of the Cs3Bi2I9 perovskite. The newly designed ultra-fast self-powered NUV–vis photodetector holds significant promise for diverse research and commercial applications.

Study on Levodopa Sensor Modified by Ti3C2 MXene

The dosage management of levodopa is of great significance in the treatment of Parkinson’s disease. Measuring the patient’s levodopa concentration helps the physician to adjust the dose in time, so as to avoid complications. In this paper, we report an electrochemical sensor based on titanium carbide (Ti3C2) MXene nanomaterials, which can sensitively reflect the change of levodopa concentration. In the study, Ti3C2/GCE electrode was prepared by a simple drop-coating method, and then the Ti3C2/Pt/GCE electrode was prepared by modifying Pt nanoparticles on the electrode surface by impregnation adsorption method. After modification, the response of the GCE electrode to levodopa before and after Ti3C2 decoration was compared by cyclic voltammetry (CV), and the diffusion control process on the electrode surface was also investigated. Then, differential pulse voltammetry (DPV) was used to explore the relationship between the peak current of the oxidation anode and the concentration of levodopa. Finally, the relationship between current and concentration at a certain time point was explored by chronoamperometry (CA), and the time charge curves were plotted to explore the functional relationship between the amount of charge exchanged in the reaction and the concentration of levodopa (Coulomb analysis method). The research shows that the coulomb analysis method has a higher detection sensitivity and linear range, and this technology is expected to be applied to the in vivo monitoring of levodopa in our future research.

Surface enhanced fluorescence potential of ZnO nanoparticles and gold decorated ZnO nanostructures embedded in a polyvinyl alcohol matrix

In this paper we report on the development of ZnO nanostructures based platforms for surface enhanced fluorescence emission. ZnO nanoparticles were prepared using a simple, low-cost chemical precipitation method and were decorated with Au nanoparticles following a controlled chemical synthesis. Nanostructures suspended in water and incorporated in a polyvinyl alcohol (PVA) matrix were used to design Rhodamine 6G-containing films by a simple drop-coating method. The PVA environment hindered the aggregation of the nanostructures yielding improved film formation capability. Surface enhanced fluorescence emission of Rhodamine 6G was obtained in the presence of ZnO nanoparticles embedded in the PVA matrix. The enhancement depended on the concentration of both the fluorophore and the ZnO nanoparticles. No fluorescence enhancement was observed in the case of Au decorated ZnO nanocomposites and both types of nanostructures exhibited fluorescence quenching of the dye outside of the PVA environment. Time-resolved fluorescence investigations revealed that in the presence of PVA neither the ZnO NPs nor the Au decorated ZnO nanocomposites modified the dye’s lifetime. In the absence of the PVA matrix, however, an additional decay pathway emerged, leading to modified fluorescence lifetime.

Self-healing artificial solid electrolyte interphase enhanced by quadruple hydrogen bonding for stable lithium metal anode

Lithium metal is considered as the ultimate anode material for lithium batteries due to its high theoretical specific capacity and lowest redox potential. However, the growth of lithium dendrites and strong side reactions seriously hinder the commercialization of Li metal anode. Here, we modify the Li metal anode with a self-healing artificial solid electrolyte interphase (SEI), where PVA-Upy with quadruple hydrogen bonds is formed on Li metal by a simple drop-coating method. This polymer artificial SEI possesses self-healing hydrogen bonds and abundant lithiophilic bonds, which can simultaneously suppress the generation of microcracks in the SEI and enable uniform deposition of Li metal. Hence, the PVA-Upy@Li symmetric cell can stably cycle for more than 2000 h (1 mA cm−2, 1 mAh cm−2) with only about 10 mV of voltage polarization. This artificial SEI provides new insight into the subsequent modification strategies of Li metal anode and can be extended to the protection of other alkali metal anodes.

Highly sensitive determination of paracetamol, uric acid, dopamine, and catechol based on flexible plastic electrochemical sensors.

Flexible sensing is an alternative to traditional sensing and possesses good flexibility and wearability. Intrinsically conductive polymers, particularly poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), have received significant attention due to their high mechanical flexibility and good biocompatibility. Here, we report the design of highly conductive and electrochemically active PEDOT:PSS-coated plastic substrate electrodes by combining N-doped graphene (NG) or S-doped graphene (SG) with methanesulfonic acid-treated PEDOT:PSS (denoted as NG-f-MSA-PEDOT:PSS/PET and SG-f-MSA-PEDOT:PSS/PET) by a simple drop-coating method. At room temperature, the NG-f-MSA-PEDOT:PSS/PET electrode demonstrated the lowest detection limits of 17.09, 33.84, 28.30, and 44.96 nM for paracetamol, uric acid, dopamine, and catechol (S/N = 3), respectively. The NG-f-MSA-PEDOT:PSS/PET electrode had good anti-interference ability and reproducibility without employing expensive noble metals and requiring much effort to polish the surface of traditional glass carbon electrodes. Most importantly, this film electrode could maintain a stable electrochemical response under different bending and crease states and had excellent mechanical stability and flexibility.

Reversibly photochromic wood constructed by depositing microencapsulated/polydimethylsiloxane composite coating

Photochromic wood was fabricated by coating microencapsulated photochromic material (MP)/polydimethylsiloxane composites onto wood using a simple drop-coating method. Urea-melamine–formaldehyde resin was used to microencapsulate the photochromic material (PM) via in situ polymerization. The concentration of the MP affected the photochromic property of the wood surface. The total color change (ΔE*) reached 82.2 when the concentration of the composite coating is 8%. Adhesion tests confirmed that the composite coating adhered firmly to the wood. This method is potentially useful for the production of functional wooden products, such as anti-counterfeiting materials and aesthetic wood.

WGM lasing in irregular cavities with arbitrary boundaries.

Because of its limited light field mode and high Q value, the whispering-gallery-mode (WGM) cavity has been widely studied. In this study, we propose a simple, rapid, low-cost and no-manufacturing technology method that we call the drip-coating method to obtain an irregular cavity with arbitrary boundaries. By using polyvinyl alcohol (PVA) solution doped with rhodamine 6G, the irregular cavity with arbitrary boundaries was drip-coated on a high-reflection mirror, forming a WGM laser. The sample was pumped with a 532 nm pulsed laser, and the single-mode WGM and multi-WGM lasing were obtained. All WGMs are the vertical oscillation modes, which originate from both the total internal reflection of the PVA/air interface and vertical reflection of the PVA/mirror interface. The other boundaries of the cavity were not involved in the reflection and could have any shape. The mechanism of producing single-mode lasing is due to the action of the loss-gain cavity. Multi-WGM lasing is attributed to at least two groups of different WGMs existing in an irregular cavity. This can be confirmed by using a microsphere model and intensity correlation method. These results may provide an alternative for the design of WGM lasers.

Preparation and photo-responsive behavior of reversible photochromic polyurethane cement composites

A smart coating based on a polyurethane cement (PUC) substrate with photochromic behavior and anti-ultraviolet performance was obtained successfully by depositing photochromic sol–gel material on the PUC surface using a simple drop-coating method. The results revealed that the PM concentration considerably affected the photochromic properties. The total color change (ΔE*) was optimum (66) at a PM concentration of 20%. The chromogenic time of the photochromic PUC was 2.4 s, and the fading time was 30 s at room temperature. Furthermore, accelerated aging and abrasion tests suggested that the treated PUC composites had excellent anti-ultraviolet properties and mechanical stability. The results indicate that the proposed photochromic PUC is a promising candidate for many applications, such as road and bridge construction and green buildings.

Fabrication of durable polytetrafluoroethylene superhydrophobic materials with recyclable and self-cleaning properties on various substrates

Most of the artificial superhydrophobic surfaces easily lose their good water repellency once they are chemically or mechanically damaged, which seriously hinders their practical application. Durable superhydrophobic materials with recyclability, low-temperature resistance, and self-cleaning properties were successfully prepared by employing silica particles and polytetrafluoroethylene via a simple drop-coating method. The as-prepared superhydrophobic materials not only show excellent superhydrophobicity but also display fascinating durability and chemical stability after a series of rigorous tests. Importantly, the debris scraped from the superhydrophobic materials can be recycled and easily reused to prepare new superhydrophobic materials. This facile strategy may pave the way for the scalable and recyclable robust superhydrophobic materials in practical applications.

Reduced Graphene Oxide/TEMPO-Nanocellulose Nanohybrid-Based Electrochemical Biosensor for the Determination ofMycobacterium tuberculosis

A novel peptide nuclide acid (PNA) electrochemical biosensor based on reduced graphene oxide (NH2-rGO)/2,2,6,6-tetramethylpiperidin-1-yl)oxyl nanocrystalline cellulose (TEMPO-NCC) for the detection ofMycobacterium tuberculosis(M. Tuberculosis) is described. In this study, the nanohybrid films NH2-rGO/TEMPO-NCC were immobilized onto screen-printed carbon electrode (SPE) via a simple drop-coating method. The electrochemical characterization of the designed electrode was investigated using cyclic voltammetry (CV) and impedance spectroscopy (EIS). Meanwhile, the sensitivity and selectivity of the designed biosensor againstM. tuberculosiswere measured by the differential pulse voltammetry (DPV). The response of the PNA probe-modified (NH2-rGO)/TEMPO-NCC demonstrated that the fabricated biosensor was able to distinguish between complementary, noncomplementary, and one-base mismatch DNA sequences using methylene blue (MB) as the electrochemical indicator. The developed electrochemical biosensor exhibited a linear calibration curve in the concentration range of1×10−8 Mto1×10−13 Mwith the limit of detection of3.14×10−14 M. The developed electrochemical biosensor has also been tested with a polymerase chain reaction (PCR) product ofM. tuberculosisDNA which has shown successful results in distinguishing between negative and positive samples of M. tuberculosis.

Highly conducting Sc and Y co-doped ZrO2 thin film solid electrolyte on a porous Ni/YSZ electrode prepared via simple drop-coating method

Dense and crack-free thin film solid electrolyte of scandium and yttrium co-doped zirconia (Sc0.08Y0.08Zr0.84O1.92) or 4S4YSZ has been successfully deposited on a NiO-YSZ porous electrode substrate via simple drop-coating deposition method. The 4S4YSZ precursor powder was synthesized using sol-gel method and the NiO-YSZ substrate, with 1:1 wt% composition, was prepared via modified glycine-nitrate combustion method. The NiO-YSZ substrates were pre-sintered at different temperatures, 1000 °C and 1300 °C, to investigate the effect on the thin film deposition and its microstructure. XRD results showed that both 4S4YSZ and NiO-YSZ exhibited a cubic crystal structure with no observable impurity peaks. SEM-EDS revealed a dense morphology of 4S4YSZ thin film with thickness of about 7μm after sintering while maintaining a desirable porous NiO-YSZ microstructure of the electrode substrate for the 1000 °C pre-sintered substrate as compared to a still porous solid electrolyte for the higher substrate pre-sintering temperature at 1300 °C. And from the conductivity measurements using EIS, the 4S4YSZ thin film revealed a notable high total conductivity of about 1.2x10-1 Scm-1 at 700 °C with 0.73 eV activation energy. Reduction of NiO/YSZ to Ni/YSZ further increases the porosity of the electrode substrate while maintaining a dense solid electrolyte thin film.

Surface and morphology analyses, and voltammetry studies for electrochemical determination of cerium(iii) using a graphene nanobud-modified-carbon felt electrode in acidic buffer solution (pH 4.0 ± 0.05).

Trace determination of radioactive waste, especially Ce3+, by electrochemical methods has rarely been attempted. Ce3+ is (i) a fluorescence quencher, (ii) an antiferromagnet, and (iii) a superconductor, and it has been incorporated into fast scintillators, LED phosphors, and fluorescent lamps. Although Ce3+ has been utilized in many industries due to its specific properties, it causes severe health problems to human beings because of its toxicity. Nanomaterials with fascinating electrical properties can play a vital role in the fabrication of a sensor device to detect the analyte of interest. In the present study, surfactant-free 1,8-diaminonaphthalene (DAN)-functionalized graphene quantum dots (DAN-GQDs) with nanobud (NB) morphology were utilized for the determination of Ce3+ through electrochemical studies. The working electrode, graphene nanobud (GNB)-modified-carbon felt (CF), was developed by a simple drop-coating method for the sensitive detection of Ce3+ in acetate buffer solution (ABS, pH 4.0 ± 0.05) at a scan rate of 50 mV s−1 using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. CV and DPV studies validated the existence of distinctive peaks at approximately +0.20 and +0.93 V (vs. SCE), respectively, with a limit of detection of approximately 2.60 μM. Furthermore, electrochemical studies revealed that the GNB-modified-CF electrode was (i) stable even after fifteen cycles, (ii) reproducible, (iii) selective towards Ce3+, (iv) strongly pH-dependent, and (v) favored Ce3+ sensing only at pH 4.0 ± 0.05. Impedance spectroscopy results indicated that the GNB-modified-CF electrode was more conductive (1.38 × 10−4 S m−1) and exhibited more rapid electron transfer than bare CF, which agrees with the attained Randles equivalent circuit. Microscopy (AFM, FE-SEM, and HR-TEM), spectroscopy (XPS and Raman), XRD, and energy-dispersive X-ray (EDX) analyses of the GNB-modified-CF electrode confirmed the adsorption of Ce3+ onto the electrode surface and the size of the electrode material. Ce3+ nanobuds increased from 35–40 to 50–55 nm without changing their morphology. The obtained results provide an insight into the determination of Ce3+ to develop an electrochemical device with low sensitivity.

The design and development of short peptide-based novel smart materials to prevent fouling by the formation of non-toxic and biocompatible coatings.

Biofouling refers to the undesirable process that leads to the accumulation of microorganisms such as bacteria or fungi on substrates. This is one of the major concerns associated with several components of our regular life such as food, health, water and energy. In the healthcare sector, biofouling on medical devices is known to cause infections, which are often resistant to conventional antibiotics and lead to increase in the number of hospital and surgery-related deaths. One of the better ways to tackle the problem of biofouling is the development of smart antifouling materials that can produce a biocompatible, non-toxic, eco-friendly and functional coating and maintain a biological environment without any adverse effect. To this end, in the present study, we have reported the design and synthesis of two simple chemically modified peptides, namely, PA1 (PFB-VVD) and PA2 (PFB-LLE). The design as well as the amino acid sequence of the peptides contains three basic components that enable their ability to (i) self-assemble into functional coatings, (ii) bind with the desired surface via the bi-dentate coordination of dicarboxylate groups and (iii) exhibit antifouling activity and generate a non-toxic biocompatible supramolecular coating on the desired surface. PA1 having aspartic acid as the anchoring moiety exhibits better antifouling activity compared to PA2 that has glutamic acid as the anchoring moiety. This is probably due to the greater adhesive force or binding affinity of aspartic acid to the examined surface compared to that of glutamic acid, as confirmed by force measurement studies using AFM. Most importantly, the simple drop-coating method promises great advantages due to its ease of operation, which leads to a reduction in the production cost and increase in the scope of commercialization. To the best of our knowledge, this is the first attempt to develop an ultra-short peptide-based smart antifouling material with a dicarboxylate group as the surface binding moiety. Furthermore, these findings promise to provide further insights into antifouling mechanisms in the future by the development of a smart material using a dicarboxylate group as an anchoring moiety.

Preparation of Co-Fe oxides immobilized on carbon paper using water-dispersible Prussian-blue analog nanoparticles and their oxygen evolution reaction (OER) catalytic activities

Carbon paper (CP) is one of the most promising metal-free gas-diffusion electrodes for fabricating sustainable energy-conversion devices such as metal-air secondary batteries using the oxygen reduction reaction (ORR) and CO2-reforming systems via the electrochemical CO2 reduction reaction (CO2RR). The common counterpart reaction for ORR and CO2RR is the oxygen evolution reaction (OER) from water. The low-overpotential OER catalyzed by nanoparticles (NPs) immobilized on CP has attracted attention for integration in energy-conversion devices. Earth-abundant and low-cost 3d transition metals have been intensively explored as OER catalysts. In this study, we have successfully prepared Fe-Co Prussian blue analog (PBA) NPs with the formulae of Fe1-xCox[Fe(CN)6]0.67·nH2O and Fe1-yCoy[Co(CN)6]0.67·mH2O, and the Fe-Co PBA NPs are dispersed into water by surface modification using [Fe(CN)6]4−. By a simple drop-coating method, the Fe-Co PBA NPs are immobilized on CP and thermally decomposed into Fe-Co oxides at 400 °C. The OER overpotentials of the Fe-Co oxides are gradually decreased by increasing the Co composition ratios, and the lowest overpotential is 0.46 V vs. RHE at 10 mA/cm2 in y = 0.6.

Ag-Au core-partial shell bimetallic nanoparticles applied in electrochemical determination of the potential endocrine disruptor oryzalin

Silver-gold core-partial shell bimetallic nanoparticles (Ag-Au BMNPs) stabilized in chitosan (CTS) were used to prepare a chemically modified electrode (CME) for the electrochemical determination of oryzalin (ORZ). The Ag-Au BMNPs were deposited on a glassy carbon electrode (GCE) by the simple drop-coating method to build the modified electrode surface (Ag-Au BMNPs-CTS/GCE). The nanoparticles dispersions were characterized by transmission electron microscopy (TEM), UV–vis spectroscopy (UV–vis) and energy dispersive X-ray spectroscopy (EDS). The CME was characterized by scanning electron microscopy with field emission gun (FEG-SEM) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of ORZ was investigated by cyclic voltammetry (CV) using the CME. Square-wave voltammetry (SWV) carried out under optimized experimental conditions demonstrated that the cathodic peak current increased with increasing concentrations of ORZ in the range of 0.1–7.0 μmol L−1. The limit of detection obtained from the calibration curve was 30 nmol L−1. The practical application of the Ag-Au BMNPs-CTS/GCE was demonstrated by determining the concentration of ORZ in a grape juice sample. The data obtained were in agreement with those provided by LC-MS/MS as a comparative technique.

Robust superhydrophobic polyurethane sponge functionalized with perfluorinated graphene oxide for efficient immiscible oil/water mixture, stable emulsion separation and crude oil dehydration

In recent years, graphene oxide (GO), prepared by the modified Hummers’ method, and its derivatives have become a focus of research owing to their outstanding physical and chemical properties and low cost. Drawing inspiration from the mussel protein, a facile and environmentally-friendly method was employed to fabricate superhydrophobic/superoleophilic reduced graphene oxide (rGO) derivative. The preparation comprises two steps: coating GO nanosheets with polydopamine (PDA) and subsequent reaction with 1 H ,1 H ,2 H ,2 H -perfluorodecanethiol. Due to the excellent adhesive ability of PDA, the resulting f PDA modified rGO nanosheets (rGO- f PDA) were firmly immobilized onto polyurethane (PU) sponge skeleton by a simple drop-coating method. The as-prepared rGO- f PDA functionalized sponge exhibited superhydrophobic behavior with a water contact angle of 162°±2°, high organic adsorption capacity, recyclability and stable oil/water separation behavior under different acidic/alkaline conditions. Due to its facile fabrication technique and outstanding properties, the superhydrophobic-superoleophilic PU-rGO- f PDA sponge holds great promise as an oil adsorbent for cleaning up large-scale pollution of oil and organic solvents, and dehydrating crude oil.

Preparation of magnetic superhydrophobic melamine sponges for effective oil-water separation

In this work, hydrophobic magnetic nanoparticles (MNPs) were successfully synthesized by the one-pot solvothermal reaction at the presence of surface modifier for the first time and characterized by SEM, EDS, TEM, WAXD, TGA, FTIR, and XPS. The fabrication of the magnetic superhydrophobic melamine sponge was realized by the deposition of the as-synthesized hydrophobic MNPs on the melamine sponge using a simple drop-coating method with the aid of silicone adhesive to achieve a firm attachment. The resultant surface-modified durable melamine sponge exhibited not only the high absorption capacities for different oil and organic solvent ranging from 39.8 g/g to 78.7 g/g but also the good reusability for absorption even after 14 absorbing-squeezing cycles. The oil absorption ability of the magnetic superhydrophobic highly-porous melamine sponge was much better than that of the magnetic superhydrophobic polyurethane sponge with relatively low porosity. Moreover, it could be found from the demonstrating experiments that the as-prepared magnetic superhydrophobic melamine sponge had the abilities to (1) remove the floating peanut oil from water followed by convenient magnetic recovery, (2) separate CH2Cl2 from water as a filter only driven by gravity, (3) absorb and collect peanut oil continuously from water surface assisted by a vacuum pump. We believe that the as-prepared magnetic superhydrophobic melamine sponge should have great potential in the effective oil-water separation.

Effective preparation of magnetic superhydrophobic Fe3O4/PU sponge for oil-water separation

Abstract Fe3O4 nanoparticles were modified by tetraethoxysilane and different amounts of trimethoxy (1H,1H,2H,2H-heptadecafluorodecyl) silane in sequence to obtain the magnetic nanoparticles with low surface energy, which could be used to construct the superhydrophobic surfaces for PU sponge, cotton fabric, and filter paper by a simple drop-coating method. Particularly, all the resultant Fe3O4/PU sponges containing different fluoroalkylsilane-modified Fe3O4 nanoparticles possessed both high water repellency with contact angle in the range of 150.2–154.7° and good oil affinity, which could not only effectively remove oil from water followed by convenient magnetic recovery but also easily realize the oil-water separation as a filter only driven by gravity. The Fe3O4/PU sponges showed high absorption capability of peanut oil, pump oil, and silicone oil with the maximum absorptive capacities of 40.3, 39.3, and 46.3 g/g, respectively. Such novel sponges might be a potential candidate for oil-water separation as well as oil absorption and transportation accompanied by the advantages of simple process, remote control by magnetic field, and low energy consumption.

Nitrogen-doped graphene/molybdenum disulfide composite as the electrocatalytic film for dye-sensitized solar cells

A composite thin film of nitrogen-doped graphene and molybdenum disulfide (NGr/MoS2) was prepared via a simple drop-coating method, and used as an electrocatalytic film for the counter electrode (CE) of a dye-sensitized solar cell (DSSC). The NGr was intended for increasing the conductivity and serving as the skeleton of the composite film, while the MoS2 with remarkable electrocatalytic ability increased the effective electrocatalytic sites in the composite film. The NGr acts as the architecture framework for MoS2 sheet, which could expose the active sites on its edge, as demonstrated in scanning electron microscopy (SEM). The weight percent (wt %) of the NGr in the composite film was optimized for obtaining the best performance to the pertinent DSSC. The NGr/MoS2 composite film shows much higher electrocatalytic ability for the reduction of I−/I3−, compared to the films of bare NGr and bare MoS2. Electrocatalytic abilities of the films were estimated by cyclic voltammetry (CV), rotating disc electrode (RDE), Tafel polarization plot, and electrochemical impedance spectroscopy (EIS) analyses. The DSSC with the NGr/MoS2 CE exhibits a solar-to-electricity power conversion efficiency of 7.82%, close to 8.25% of the DSSC with a platinum CE film. The low-cost NGr/MoS2 composite film is a potential alternative to replace the expensive platinum film for use as the catalytic film on the counter electrode of a DSSC.