Water-splitting presents a viable solution to expanding energy needs. To maximise water-splitting performance, transition metal sulphides, a very efficient electrocatalyst, have been extensively ...researched. It is unable to generate hydrogen (H2) and oxygen (O2) because to active sites and weak electrical conductivity. Some carbon-based materials offer superior dispersion capacities and bigger active sites for charge transfer to circumvent these restrictions. This work presents an efficient electrocatalyst combining carbon nanotubes (CNTs) and electrochemically active Nickel sulphides, Ni17S18 (NiS), synthesized by using a wet-chemical approach. The improved electrocatalytic performance of NiS@CNTs can be attributed to higher surface area and higher electrical conductivity of CNTs. Furthermore, linear-sweep voltammetry (LSV) and electrochemical impedance analysis (EIS) were also utilized for the electrochemical investigations. The addition of CNTs to NiS showed a over-potential of 330 mV at 40 mA cm−2, with a Tafel slope of 47 mV dec−1 for OER. Similarly, we have also investigated the HER activity of the as-prepared electrocatalysts at the same current density, having a over-potential of 280 mV with a Tafel slope of 102 mV dec−1.
•NiS and NiS@CNTs nanocomposites were synthesized by the precipitation method.•NiS@CNTs exhibits better HER and OER performances as compared to the bare NiS.•NiS@CNT shows Tafel slope 47 and 102 mVdec−1 for OER and HER singly.•Overpotential of 330 mV-OER and 280 mV-HER was reached to current density 10 mAcm−2.
The increasing CO 2 concentration in the atmosphere has caused profound environmental issues such as global warming. The use of CO 2 as a feedstock to replace traditional fossil sources holds great ...promise to reduce CO 2 emissions. The electrochemical conversion of CO 2 has attracted much attention because it can be powered by renewable sources such as solar energy. In this review article, we provide insight into the important parameters when studying CO 2 RR and give a comprehensive review on the description of synthesis methods with electrocatalytic CO 2 reduction over bimetallic copper-based materials. Due to the important bibliographic data on Cu bimetallic materials, we have limited this review to Sn, In, Pd, Zn and Ag. At the end of this review, challenges and perspectives for further upgrading have been included to briefly highlight the important future considerations of this rapidly growing technology.
The primary goal for the development of energy-storage devices is to find affordable ways to increase their efficiency, activity, and stability. In this regard, transition metal oxide mainly MoO3 ...enhances the electrochemical properties of the material due to various oxidation states. On the other hand, carbonaceous materials, such as reduced graphene oxide, provide a large surface area that increases the conductivity of nanomaterials. In this work, we have synthesized pristine and codoped MoO3 material using the co-precipitation route. While the r-GO based composite was prepared by a simple sonication approach. The prepared composite material showed a higher specific capacitance of 987 F/g than the pristine and codoped material. The BAMO@r-GO discharges after 346 s which was the higher time of discharge than that of pure and codoped material. Moreover, the obtained results from EIS measurement confirmed that the composite material showed less resistance than all other synthesized materials. The synergistic effect between the r-GO and BAMO materials is the reason for the higher supercapacitor performances of BAMO@r-GO. Based on these results, the fabricated BAMO@r-GO material can be effectively utilized as an electrode material in electrochemically powered energy storage devices.
The increasing CO2 concentration in the atmosphere has caused profound environmental issues such as global warming. The use of CO2 as a feedstock to replace traditional fossil sources holds great ...promise to reduce CO2 emissions. The electrochemical conversion of CO2 has attracted much attention because it can be powered by renewable sources such as solar energy. In this review article, we provide insight into the important parameters when studying CO2RR and give a comprehensive review on the description of synthesis methods with electrocatalytic CO2 reduction over bimetallic copper-based materials. Due to the important bibliographic data on Cu bimetallic materials, we have limited this review to Sn, In, Pd, Zn and Ag. At the end of this review, challenges and perspectives for further upgrading have been included to briefly highlight the important future considerations of this rapidly growing technology.
Exploring the cost-effective and earth-abundant electrocatalyst for efficient bifunctional activity is very challenging these days. The main reason is very slow OER (oxygen evolution reaction) ...kinetics as compared with HER (hydrogen evolution reaction). An electrocatalyst with enhanced kinetics towards OER and HER is highly required, which may be attributed to a larger surface area, an increased number of active sites, and lower charge transfer resistance. In this paper, we have reported a very efficient bifunctional Ni2O2(OH)/CNTs electrocatalyst by a facile ultrasonication route followed by annealing for OER/HER performance in an alkaline solution. The Ni2O2(OH)/CNTs electrocatalyst exhibits a lower overpotential of 228 mV and 270 mV during OER to accomplish a current density of 40 and 100 mAcm−2 while it requires a 368 mV and 418 mV overpotential during HER to achieve a current density of 40 and 100 mAcm−2. The prepared Ni2O2(OH)/CNTs electrocatalyst has a lesser Tafel slope (132 mVdec−1; OER, 115 mVdec−1; HER) as compared to Ni2O2(OH) (239 mVdec−1; OER, 124 mVdec−1, HER). Ni2O2(OH)/CNTs exhibit reduced charge resistance, enhanced electrochemical active surface area, greater carrier concentration, and a higher exchange current density, which confirms its superior bifunctional electrocatalytic activity. This work provides an economical and affordable means to prepare superior, efficient bifunctional electrocatalysts for widespread commercial applications.
•CNTs-based Ni2O2(OH) electrocatalyst has been prepared for bifunctional electrocatalytic activity.•The ultrasonication method was adopted for the synthesis of bifunctional electrocatalysts.•The Ni2O2(OH)/CNTs exhibited an OER onset potential of 1.46 V versus RHE, while for HER it is 0.375 V versus RHE.•The bifunctional material exhibited a 228 mV overpotential to attain 40 mAcm−2 current density during OER.•The prepared catalyst exhibited 368 mV overpotential to reach −40 mAcm−2 current density during HER performance.
Organic-inorganic halide perovskites with enhanced energy orientation in optoelectronic devices will also have a huge impact on solar cell performance because of their low manufacturing cost and long ...lifetime. The pure methylammonium lead iodide (CH3NH3PbI3 or MAPbI3) films are coated on FTO-glass substrates by sol-gel spin coating technique. Gold (Au) ions with fluence rates of 2x1014 and 4x1014 ions/cm2 are implanted on these films to enhance their structural, morphological and photovoltaic performance. The cubic crystal structure is present in all of the films. The grain size of the film implanted with 2x1014 ions/cm2 is large. According to AFM and FESEM images, the grains in the pure material are tightly packed and connected to one another with distinct grain boundaries, but when Au ions are implanted, the size of the grains increases. The optical characteristics like dielectric constant, bandgap, refractive index, and extinction coefficients are measured using the UV–Vis spectrometry technique. All films have direct band gap and the films irradiated with 2x1014 ions/cm2 has low band gap energy (1.52 eV). The solar cells of these films are manufactured. Each cell performs well overall. The Mott Schottky analysis, charge transfer resistance, and space charge limited current calculations all offer strong support for the excellent efficiencies of such films. The cell fabricated with 2x1014 ions/cm2 implanted Au ions has large a short-circuit current density of 10.57 mA/cm2, a Fill-Factor of 0.82, open circuit voltage of 1.03 V, and an efficiency of 8.94%.
The scarcity of non-renewable energy sources and rising worldwide temperatures are significant challenges. Electrochemical water splitting using low-cost materials (metals and their oxides) is a ...highly efficient and cost-effective method of producing both hydrogen and oxygen. Apart from precious metals, carbon-based materials have also shown effectiveness in catalyzing these reactions. To minimize overpotentials and enable practical applications, metal oxide encapsulation in graphite layers has demonstrated significant activity for both HER and OER. Metal oxides are known for their high conductivity and mechanical strength, making them suitable candidates for this task. In the present research, we report the design of a composite (Ni, Mn)-ZnO/g-C3N4 ((Ni, Mn)-CNZ) electrocatalyst with improved electrocatalytic performance. The coprecipitation of (Ni, Mn)-ZnO with graphitic carbon nitride (g-C3N4) produced the composite material. The structure of the electrocatalyst was analyzed using characteristic techniques such as FTIR, EDX, SEM, and XRD. Electrodeposition on FTO glass is employed to facilitate studies of water distribution. The (Ni, Mn)-CNZ composite exhibits excellent electrochemical water-splitting behavior, with low overpotentials, 380 mV (OER) and 288 mV (HER), reaching a current density of 10 mA cm−2 compared to Ni-CNZ and Mn-CNZ. This highlights the potential of (Ni, Mn)-CNZ as a highly effective electrocatalyst for water splitting.
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In this study, cerium oxide nanorods (CeOsub.2-NRs) were synthesized by using the phytochemicals present in the Dalbergia sissoo extract. The physiochemical characteristics of the as-prepared ...CeOsub.2-NRs were investigated by using ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). The SEM and UV-VIS analyses revealed that the acquired nanomaterials possessed a rod-like morphology while the XRD results further confirmed that the synthesized NRs exhibited a cubic crystal lattice system. The antioxidant capacity of the synthesized CeOsub.2-NRs was investigated by using several in vitro biochemical assays. It was observed that the synthesized NRs exhibited better antioxidant potential in comparison to the industrial antioxidant of the butylated hydroxyanisole (BHA) in 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The biochemical assays, including lipid peroxidation (LPO), total antioxidant capacity (TAC), and catalase activity (CAT), were also performed in the human lymphocytes incubated with the CeOsub.2-NRs to investigate the impact of the NRs on these oxidative biomarkers. Enhanced reductive capabilities were observed in all the assays, revealing that the NRs possess excellent antioxidant properties. Moreover, the cytotoxic potential of the CeOsub.2-NRs was also investigated with the MTT assay. The CeOsub.2-NRs were found to effectively kill off the cancerous cells (MCF-7 human breast cancer cell line), further indicating that the synthesized NRs exhibit anticancer potential as well. One of the major applications studied for the prepared CeOsub.2-NRs was performing the statistical optimization of the photocatalytic degradation reaction of the methyl orange (MO) dye. The reaction was optimized by using the technique of response surface methodology (RSM). This advanced approach facilitates the development of the predictive model on the basis of central composite design (CCD) for this degradation reaction. The maximum degradation of 99.31% was achieved at the experimental optimized conditions, which corresponded rather well with the predicted percentage degradation values of 99.58%. These results indicate that the developed predictive model can effectively explain the performed experimental reaction. To conclude, the CeOsub.2-NRs exhibited excellent results for multiple applications.
