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The development of greatly stable and cost-effective electrocatalysts for urea electro-oxidation reactions (UERs) is urgent and challenging for promoting urea removal in the wastewater and advanced energy conversion devices. We demonstrated that nickel-iron borate (NiFe-B) electrocatalysts supported on carbon paper (CP) for UERs through a one-pot solvothermal method. NiFe-B electrocatalysts were obtained with numerous Ni/Fe molar ratios in the precursors, and the physicochemical features of the NiFe-B were examined by X-ray diffraction, scanning and transmission electron microscope, and X-ray photoelectron spectroscopy. The optimized NiFe-B/CP exhibited a low onset potential (Eonset = 0.287 V vs. SCE) with a Tafel slope of 27.9 mV/dec on CP, demonstrating much greater performance UERs. Furthermore, the NiFe-B/CP catalysts have shown a superior activity for the UERs in alkaline solution and exhibit more than two-fold enhancement in activity than Ni-B. Facile, cost-effective fabrication and highly efficient urea oxidation create the NiFe-B electrodes as attractive materials for UERs.

We demonstrate the synergetic effect of Na2MoO4-doping and vacuum-annealing on dendritic nanostructured bismuth oxide (Bi2O3) thin films prepared by electrodeposition for visible-light-assisted photoelectrochemical (PEC) water oxidation. After evaluating various extents of Na2MoO4-doping as well as vacuum-annealing temperatures, it was evidenced that both Na2MoO4-doping and vacuum-annealing significantly improved the efficiency and PEC water oxidation performance. Compared to the undoped Bi2O3 photoanode, the optimized Na2MoO4-doped Bi2O3, after vacuum-annealing, resulted in more than 25-fold enhancement in the photoanodic current density to 1.06 mA/cm2 at 1.23 VRHE under AM1.5 G illumination. The PEC enhancement is credited mainly to the increased PEC surface active sites in the Na2MoO4-doped vacuum annealed sample. Confirmed by combined XPS and Mott-Schottky (M − S) analysis, vacuum annealing resulted in surface oxygen vacancies that can contribute to the photocatalytic activity. Besides, Na2MoO4-doping resulted in reduced dimensions of the dendritic structure, revealed by FE-SEM and XRD measurements, resulting in larger surface area and, therefore, larger surface/electrolyte contact. This dual strategy (metal doping + vacuum annealing) can be generalized to assemble photoanodes of other materials used for the production of solar fuels. Our results make a valuable step towards efficient Bi2O3/BiVO4 pn heterojunctions.

The aim of the present work was to evaluate the performance of polypropylene (PP)/sisal fiber (SF)/banana fiber (BF) and chitosan-based hybrid (chitosan(CS)/SF)/BF) composite materials for the adsorptive removal of cadmium (Cd) ions from water waste. Polypropylene is harnessed for its importance in forming strong composite materials for various applications. Chitosan biopolymer encloses a great deal of amino and hydroxyl groups, which provide effective removal of Cd ions from wastewater. The batch adsorption studies proved that the removal of Cd ions was pH-dependent and attained optimum at pH 5.5 for both the composites. Langmuir and Freundlich models were applied for the obtained experimental values. Based on the R2 values, it was evidenced that the adsorption process was best fitted with the Freundlich isotherm than Langmuir. The sorption capacity of CS/SF/BF hybrid composite (Cmax = 419 mg/g) is higher than PP/SF/BF composite (Cmax = 304 mg/g), and allows multilayer adsorption. Kinetics studies revealed that the pseudo-second-order model was followed during the removal of Cd ion from wastewater. The overall evaluation proved that though both the adsorbents are suitable for the removal of Cd ions, the efficiency of CS-based ternary composite material is better than PP-based composite.

In the present energy scenario of the world, hydrogen with high energy content seems to be a better green alternative to depleting fossil fuels. Here we describe an innovative and efficient iron nickel diselenide (Ni0.5Fe0.5Se2) as a potential electrocatalyst for hydrogen evolution reaction in acid media. Ni0.5Fe0.5Se2 has been fabricated by means of one-step hydrothermal process supported by multi walled carbon nanotubes (MWCNTs). Ni0.5Fe0.5Se2/MWCNTs electrocatalyst has been prepared from cost-effective and highly available earth-abundant elements. The crystalline structure, morphology and elemental composition of Ni0.5Fe0.5Se2/MWCNTs with different weight percentage (1, 3, 5, 7%) of MWCNTs in the composite. The electrocatalysts has been successfully evaluated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), field emission scanning electron microscopy (FE-SEM). Cyclic voltammetry (CV), Tafel and electrochemical impedance analysis have been utilized to investigate. Among the investigated weight percentages, the electrocatalyst with 3 wt% of MWCNT exhibited high hydrogen evolution activity with a current density of 10 mA/cm2 at an overpotential 200 mV with a Tafel slope of 71 mVdec−1. The synergistic efforts between Ni0.5Fe0.5Se2 and MWCNTs in the promotion of hydrogen evolution activity is ascribed to active sites, low electron transfer resistance and superior electrochemical kinetics of molecular hydrogen (H2) production.

A crystalline mesoporous cobalt phosphate (meso-CoPi) electrocatalyst is prepared using liquid crystal template of non-ionic surfactant of Brij®78. The physicochemical investigations of the electrocatalyst executed by surface area analyzer, XRD, transmission electron microscope submits creation of a mesoporous crystalline nanostructured of meso-CoPi with a surface area of 124 m2 g−1. This is an 10-fold greatness superior than that for bulk-CoPi particles produced without surfactant template. The meso-CoPi electrocatalyst comprises of metallic cobalt layered with a cobalt-oxo/hydroxo-phosphate layer which facilitates the electro-oxidation of methanol at modest overpotential of

Herein, we have examined the effect of tungsten trioxide (WO3) doping in graphitic carbon nitride (g-C3N4) photocatalysts towards photodegradation of organic pollutant in aqueous medium. A sequence of visible light driven WO3/g-C3N4 composites were synthesized at various mole ratios (1, 2, 3 and 5%) of WO3 into g-C3N4 via simple and short-time wet-impregnation method. The fabricated photocatalytic materials were investigated by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, UV–vis diffuse reflection spectroscopy (DRS), photoluminescence (PL) and scanning electron microscopy (SEM). The photocatalytic performance of the fabricated photocatalysts were assessed by the degradation of acid orange 7 (AO7) in visible-light illumination. The WO3/g-C3N4 composites were found to be exhibit an improved visible-light induced photocatalytic performances compared to the pure WO3 and g-C3N4. However, among the different composites, the optimized 3 wt% WO3/g-C3N4 composite has shown complete (100%) degradation efficiency of AO7 after 75 min which is superior than the pure g-C3N4. This synergistic enhancement might be credited to its increased light absorption in visible-light region and the photoexcited electron transfer from g-C3N4 to WO3 catalyst surface and enhanced charge separation efficiency. Additionally, the photo-electrochemical measurements of 3 wt% WO3/g-C3N4 composite has exhibited a quicker migration of the photo-excited charge-carriers. The radical scavenging studies inferred that the O2 − are the key species accountable for the degradation of AO7 for fabricated WO3/g-C3N4 composite materials. Hence, the higher photocatalytic activity, long-term stability and recyclability of WO3/g-C3N4 composite has displayed it is a auspicious material for the photocatlytic degradation of organic contaminant applications.

The development of efficient, cost-effective routes to prepare non-platinum-based electrocatalysts is a significant scientific challenge in water-splitting systems. A multifunctional electrocatalyst for the hydrogen evolution, oxygen evolution, and oxygen reduction reactions (HER/OER/ORR) involved in the water-splitting process was fabricated using a simple and eco-friendly strategy. The present study involves the simple synthesis of nanostructured nickel selenide (NiSe) via a hydrothermal method. The different phases of nickel selenide and their dependency on the precursor concentration were analyzed using X-ray diffraction (XRD). The morphologies of coral-like structured pure and Mo-doped NiSe (Ni1-xMoxSe) samples were investigated systematically using scanning electron microscopy (SEM). The as-prepared Ni0.5Mo0.5Se material showed an enhanced electrochemical activity of 1.57 V @ 10 mA/cm2 for OER and 0.19 V @ 10 mA/cm2 to HER, and follows the Volmer-Heyrovsky for HER mechanism. In addition, the electrocatalyst exhibits a large electrochemical surface area and high stability. Therefore, the hydrothermally synthesized Ni1–xMoxSe has been proven to be a perfect platinum-free trifunctional electrocatalyst for water splitting process.

BiVO4 is one of the most promising semiconductors for photoelectrochemical water splitting. BiVO4 is, however, limited by poor charge separation and slow oxygen evolution dynamics, for which surface modification with oxygen evolution catalysts (OECs) becomes indispensable. Among many OECs, Prussian blue type coordination polymers have lately attracted an escalating research interest attributable to their low cost, chemical robustness and easy synthesis using nontoxic earth-abundant elements. In this study, we report a simple method for efficient surface modification of Zr-doped BiVO4 nanostructured electrodes with an amorphous Ni-Fe based Prussian blue (NiFePB) polymer. The method resulted in a remarkable 10-fold enhancement of photocurrent (3.23 mAcm−2 at 1.23 V versus the reversible hydrogen electrode RHE) and a low onset potential of 0.208 V versus RHE, which are both records for Prussian blue (PB) type materials. Our coating method results in a (Zr)BiVO4/NiFePB core-shell structure, in which a 10–15 nm NiFePB shell makes a superior conformal coating with complete coverage on the (Zr)BiVO4 nanoparticles. The high conformity and amorphous nature of the coating are believed to be key features for the high photocatalytic activity and for a high photocorrosion resistance of the photoanodes during > 50 h of AM1.5 G solar illumination. Our method illustrates the large potential of Prussian blue type materials, when properly coated, as efficient and highly stable OECs.

Supercapacitors (SCs) has gained an impressive concentration by the researchers due to its advantages such as high energy and power densities, long cyclic life, rapid charge–discharge rates, low maintenance and desirable safety. Hence it has been widely utilized in energy storage and conversion devices. Among the different components of SC, electrodes play a vital role in the performances of SCs. In this review, we present the recent advances in 2-D nanostructured metal nitrides, carbides, and phosphides based materials for SC electrodes. Finally, the electrochemical stability and designing approach for the future advancement of the electrode materials are also highlighted.

An efficient BiFeO3/BiOI composite photocatalytic material was fabricated via simple wet impregnation process and photocatalytic performances were evaluated by the catalytic degradation of Rhodamine B (RhB) and bisphenol A (BPA) in visible-light illumination. Structural, light absorption and morphological features of the fabricated photocatalysts were investigated by various spectroscopic and microscopic procedures. The photodegradation efficiency results demonstrated that the BiFeO3/BiOI composite with 2 wt% loading of BiFeO3 (2% BiFeO3/BiOI) displayed the higher photocatalytic activity than various other BiFeO3 loadings, pristine BiOI and BiFeO3. A maximal photodegradation efficiency of RhB and BPA are ∼100% and 71% were accomplished using the optimized composite when compared to merely ∼56% and ∼36% using pristine BiOI, respectively. The significant enhancement in the photodegradation rates of RhB (∼5 times) and BPA (∼2 times) pollutants using 2% BiFeO3/BiOI composite is credited to the efficient charge separation of photoinduced hole-electron pairs by transferring the electrons from BiOI to BiFeO3 catalyst surface. The photostability results revealed that the compost was retained their photocatalytic activity up to 3 cycles of degradation experiments. The higher photocatalytic activity, long time stability and reusability tests exposed that the BiFeO3/BiOI composite might be a potential photocatalytic material for topical applications in the field of water treatment.

This work reports the photo-electrochemical enhancement of alkali water oxidation at mesoporous TiO2 (m-TiO2) photoanode prepared by evaporation-induced self-assembly (EISA) approach and photomodified with Au nanoparticle (Au/m-TiO2). The physicochemical characterizations of the modified photoanodes showed the uniform incorporation of gold nanoparticles having a diameter range of 3–5 nm into the mesoporous TiO2 substrate. The photo-electrochemical investigations demonstrate that the Au/m-TiO2 modified catalysts under the simulated solar light illumination exhibit excellent photoelectrochemical activity for alkali water oxidation and photocurrent density of 1.30 mA/cm2 has been achieved within the potential window of 0.1–1.7 V vs. reference hydrogen electrode (RHE), which is a 2.5 times higher photocurrent than that observed at bare m-TiO2 anode. An apparent oxygen evolution rate of 45.80 mmol/mg h was observed at a potential of 1.25 V vs RHE for Au/m-TiO2 which is significantly higher than that obtained for bare m-TiO2 (12.5 mmol/mg h). The mesoporous TiO2 materials modified with suitable metal nanoparticles via ex-situ photodeposition have shown substantial current gain during the photo-electrochemical water splitting reaction due to the boosting effect of the plasmonic nanostructure.

Herein, visible-light driven BiFeWO6/TiO2 nanocomposites photocatalysts were successfully synthesized by an incipient wet-impregnation method. The as-synthesized BiFeWO6/TiO2 nanocomposites were explored by using various techniques of X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy (DRS), photoluminescence (PL), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoelectrochemical (PEC) studies to investigate the material formation, surface morphology, electrochemical and optical behaviors. Furthermore, the photocatalytic efficiency of fabricated BiFeWO6/TiO2 nanocomposites was also evaluated towards the degradation of acid orange 7 (AO7). From the degradation results, it revealed that 1% BiFeWO6/TiO2 nanocomposite demonstrated superior photocatalytic performance than its comparison with pure components. This optimized 1% BiFeWO6/TiO2 nanocomposite was found to achieve complete degradation of AO7 within 60 min and also it showing a rate constant value of0.054 min−1 which is much superior to the pure TiO2. This improvement might be credited to its strong light absorption ability in a visible-light region and the low recombination rate of hole-electron pairs. Also, the BiFeWO6/TiO2 nanocomposite has an exceptional photostability and reusability character along with an excellent photo-electrochemical activity. Therefore, it can be well useful material for removing organic pollutants in the aqueous environment. Finally, a probable mechanism is suggested for the photodegradation of AO7 over as-synthesized BiFeWO6/TiO2nanocomposite material.

Bismuth vanadate (BiVO4) is a promising visible-light driven semiconductor photocatalyst with various benefits such as low production cost, low toxicity, high photostability, resistance to photo-corrosion and narrow band gap with a good response to visible-light excite. However, the fast recombination of photoinduced charge carriers restricts their photocatalytic activity. In the past decades, many attempts were adopted to enhance the photocatalytic activity of BiVO4. Significant advances in understanding the fundamental issues and the development of an efficient photocatalyst have been made in current years. In this review, we have provided a comprehensive overview of the latest progress on the morphology control and growth mechanism of BiVO4 micro/nano-structures, doping with metal and non-metal elements and semiconductor coupling along with some highlights in the photodegradation of organic pollutants under visible-light illumination. This review may benefit the researchers and engineers in the arena of material chemistry for designing new BiVO4 based photocatalysts with low production cost and high efficiency.

Herein, we have prepared different weight percentages of (10%, 20% and 30%) of α-FeOOH on BiOI visible light active α-FeOOH/BiOI nanocomposite via facile wet impregnation method. The rod-like morphology of α-FeOOH and flake-like morphology of BiOI photocatalyst were fabricated via hydrothermal process. The synthesized photocatalyst were explored by different characterization methods such as FT-IR, XRD, FE-SEM, EDAX, HR-TEM and UV–vis DRS. The photocatalytic behavior was assessed by the photodegradation of Rhodamine B (RhB) under visible-light illumination. The optimum 10% α-FeOOH/BiOI nanocomposite showed a superior photocatalytic activity than other photocatalysts. About 91% degradation of RhB was witnessed after 90 min under illumination. Further, the photoluminescence (PL) and photoelectrochemical measurements revealed that the 10% α-FeOOH/BiOI nanocomposite showing enhanced charge carrier separation than other photocatalysts. The superior photocatalytic activity and photostability revealed that the α-FeOOH/BiOI nanocomposite could be a promising material in wastewater treatment and other environmental remediation applications.

Antibiotic drugs are comprehensively used in treating infectious animals, mainly food-producing animals, which may severely affect other living organisms. Hence, it is necessary to develop a device to monitor trace level of these drug in food samples by a sensitive method. Carbon nanomaterials are usually fabricated as a disposable electrode in an electrochemical sensing application; however, its hydrophobicity nature causes poor electrode stability. An effective strategy is followed in this study to improve the aqueous dispersion of vapor-grown carbon fiber (VGCF) materials through the bio-inspired polydopamine (PDA) functionalization approach. The PDA functionalized VGCF (PDA-VGCF) is significantly characterized by spectroscopic and microscopic methods. The improved hydrophilicity of PDA-VGCF composite materials can offer an easy way to prepare catalyst slurry for the coating of a glassy carbon electrode (GCE) and used to determine the chloramphenicol (CAP) antibiotic drug. Interestingly, cyclic and differential pulse voltammetry studies are performed to observe the electrocatalysis of CAP using PDA-VGCF/GCE, displays a good linear response range (0.01–142 µM), lower detection limit (3 nM), and higher sensitivity (0.68 µAµM−1 cm−2) with long-time stability up to 30 days. Furthermore, PDA-VGCF/GCE shows an admirable selectivity while existing with other interference compounds and practical feasibility are also evaluated in apple juice, milk, and honey samples.

In this study, visible light driven BiFeWO6/BiVO4 nanocomposite was synthesized via simple additive-free wet-chemical process. Various physicochemical characterization methods such as X-ray diffraction (XRD), fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electrons microscopy (TEM), energy dispersive spectroscopy (EDS) spectra, UV visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical measurements were performed to examine the structure, surface morphology, electrochemical and optical behavior of the synthesized material. The photocatalytic performances of the as-synthesized materials were assessed by the photodegradation of methylene blue (MB) in visible-light illumination. The optimum BiFeWO6/BiVO4-2 nanocomposite has shown 95% degradation efficiency of (MB) after 90min. This is about 10-folds higher than that of pristine bismuth vanadate (BiVO4). This enhancement of photocatalytic performances is credited to the photogenerated electrons transfer from BiVO4 to BiFeWO6 catalyst surface and thereby reduced the recombination process. The higher photocatalytic activity, long-term stability and recyclability results have revealed that the BiFeWO6/BiVO4 nanocomposite could be an auspicious material for the elimination of organic contaminants present in the ecosystem. Moreover, a probable mechanism for the catalytic degradation of MB dye over BiFeWO6/BiVO4 system is also proposed based on experimental results.

This article describes a simple non-faradaic impedimetric sensor comprised of L-Cysteine self-assembled on top of an interdigitated gold electrode for the direct detection of lead ions (Pb(II)) in tap water. The sensor consists of only two electrodes and does not require redox probe during detection. During the detection of Pb(II) in tap water, changes in capacitance were observed with a sensitivity of 9.4 nF/log(nM) and a limit of detection of 45 pM at a biasing frequency as low as 10 Hz, which is well below the World Health Organization WHO recommendation for Pb(II). The sensor demonstrated satisfactory selectivity toward Pb(II) in comparison to Sn(II), Zn(II), Cu(II), Na(II), Mg(II) and Ca(II). In addition, the system allows a wide working frequency window up to ∼ 5 kHz, for which higher sensitivities can still be obtained. ATR-FTIR spectrum confirmed the functionalization of L-Cysteine onto interdigitated gold electrodes. Furthermore, XPS results confirmed complete thiolate-gold bonding, with no adsorbed sulfur or unbound thiol between L-Cysteine and the electrode surface. Also, the binding of Pb(II) to L-Cysteine was confirmed by XPS to take place mainly through the carboxyl group. The reported method is promising for constructing miniaturized sensors for the direct detection of Pb(II) in low-volume tap water samples.

The present study is to demonstrate the molybdenum sulphide (MoS2) modified metal ion doped manganese oxide (MnO2) effect for sono-catalytic dye degradation application. The as-prepared additive (5% and 10% MoS2) modified Nickel-cobalt modified porous Manganese oxide (Ni─Co─MnO2) catalysts have shown complete dye discoloration and good sorption activity due to improved higher surface area values compared to undoped pristine manganese oxide. X-ray diffraction pattern confirms the formation of α-phase of MnO2 with tunnel structure formation due to present synthesis method. The thermal stability and structure-property relationship of prepared catalysts have studied by various physico-chemical methods. The thermal stability of the prepared catalysts have stable up to 500─600 °C with Mn2O3 phase and it is further transform into more stable Mn3O4 phase. The fascinating flaky morphology of MnO2 and nanofibers of MoS2 nanoparticle exfoliation into porous manganese oxide matrix, which is clearly examined by SEM and HR-TEM. The particle size and zeta potential values are described for their respective surface property alteration. The pristine Ni─Co─MnO2 and additive modified catalyst have exhibiting effective and complete degradation for Congo red (CR) dyes after modification by MoS2. The re-peated results are obtained for re-used catalyst for dye degradation in the sono-catalytic process. The sono-catalytic mechanism insights of cong red degradation in the presence of MoS2/Ni─Co─MnO2 catalyst have also been demonstrated. The cycle stability for dye degradation and reusability of the as-prepared catalysts show effective repeating activity up to 95%.

The demand for sustainable energy storage and production is vital and continues to grow with increasing human population. Energy utilization and environmental protection demand urgent attention in the development of energy devices, including the expansion and assessment of earth abundant and inexpensive materails. Recently, two-dimensional (2D) structured graphene has emerged as an outstanding energy material due to its excellent physicochemical properties, for example, high thermal and electrical conductivity, high surface area, strong mechanical strength, and an excellent chemical stability. However, pure graphene has a band gap of zero significantly limiting its application as a material. Among the various approaches used to alter the properties of graphene is doping with a heteroatom, which has been shown to be an efficient process in tailoring the properties of 2D-graphene. Heteroatom-doped graphene has several improved physicochemical properties, making graphene a favorable material for application in various fields. In this review, we report the usage and advancement of heteroatom-doped graphene materials in various energy conversion and storage technologies, including supercapacitors, batteries, dye-sensitized solar cells, and hydrogen production from electrocatalytic water splitting. Furthermore, we have also highlighted the recent developments made to date and systematically discuss physicochemical mechanisms, and the precise advantages obtained by the doping of heteroatoms. Finally, the challenges and future perspectives for heteroatom-doped graphene materials are outlined. The information provided in this review should be useful to any researchers involved in the field of graphene research for wide-ranging applications, and structural-oriented (morphology, structure, size and composition) research.

In this work, we have demonstrated a prompt anodic electrochemical exfoliation of graphite into graphene sheets (GS) in aqueous media. For the synthesis of GS, a constant potential of +10 V has been applied between two identical graphite sheets in 0.1 M aqueous ammonium sulfate. The exfoliated GS were characterized via standard analytical tools such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy with energy dispersive spectrum (FE-SEM with EDS). Further, the electrochemical performance of GS coated Ni foam (GS/Ni foam) was assessed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques in 2 M KOH. The quasi-rectangular shaped voltammograms and triangular shaped GCD curves in a three-electrode system was evidenced the double-layer capacitance of GS/Ni foam, which exhibited maximum specific capacitance of 84.82 and 40. 83 F/g at 2 mV/s, and 0.1 A/g of current density, respectively. Moreover, the symmetric two-electrode performance of GS/Ni foam was also examined, which showed good energy density (3.03 Wh/kg) and power density (562.5 W/kg). This study proves that the anodically exfoliated GS can act as a good symmetric supercapacitor in KOH.

In this work, an efficient visible-light active BiFeWO6/BiOI nanocomposite was fabricated by mixing various weight percentages (1%, 2% and 3%) of BiFeWO6 on BiOI via facile one-step wet impregnation method. The synthesized BiFeWO6/BiOI nanocomposite were investigated by XRD, FT-IR, FE-SEM, HR-TEM, EDAX, UV–vis DRS and BET. The photocatalytic activity of synthesized BiFeWO6/BiOI nanocomposite photocatalysts were assessed for the photodegradation of Rhodamine B (RhB) under visible-light illumination. The optimum 1% BiFeWO6/BiOI nanocomposite showed 92% efficiency of RhB after 90 min. The photoluminescence (PL) and photoelectrochemical measurements revealed that the 1% BiFeWO6/BiOI nanocomposite greatly enhanced the charge carrier separation and thus by slowing down the recombination rate of the photoinduced charge carriers. The radical trapping experiment inferred the h+ and O2 − as the important active species responsible for the photodegradation of RhB. The higher photocatalytic activity and recyclability revealed that the BiFeWO6/BiOI nanocomposite could be a promising material in wastewater treatment and other environmental remediation applications.

Nickel-cobalt oxides nanocomposites with different Ni/Co ratios are fabricated by micro-wave assisted synthesis. The texture, morphology, BET surface area and electrochemical performance are found strongly related to Ni and Co concentration. The results illustrate that a hierarchical porous assembly of nanoparticles of ∼10 nm was obtained, and the ratio of Ni/Co in the nanocomposites was nearly identical to its precursors. The electro-oxidation behavior of meso-nickel-cobalt oxides outperform pure NiO and Co 3 O 4 for methanol oxidation reaction (MOR). The Ni-Co-O nanocomposite displays a highly stable response during MOR and it considered to a favorable material to develop non-Pt based fuel cells.

Advanced electrocatalysts for the fabrication of sustainable hydrogen from water splitting are innermost to energy research. Herein, we report the growth of iron diselenide (FeSe2) nanorods on graphene oxide (GO) sheets using two-step process viz., simple hydrothermal reduction and followed by wet chemical process. The orthorhombic phase of FeSe2 incorporated GO nanosheet was developed as a low-cost and efficient electrocatalyst for hydrogen evolution reaction (HER) by water splitting. The phase purity, crystalline structure, surface morphology and elemental composition of the synthesized samples have been investigated by UV–visible absorption spectroscopy (UV–vis), fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDS). Voltammetry and Tafel polarization methods have been utilized to assess the performance of various weight ratio of GO nanosheet in FeSe2 nanorods towards H2 evolution. Detailed electrochemical investigations revealed that the 30% FeSe2/GO composite showed a tremendous electrocatalytic HER activity in acidic medium with high cathodic current density of 9.68 mA/cm2 at η = 250 mV overpotential and with a Tafel slope of 64 mV/dec. The 30% FeSe2/GO composite offers a high synergistic effect towards HER activity, which is mainly due to high electrochemical active catalytic sites, low charge-transfer resistance and enhanced electrocatalytic performances of H2 production. The present analysis revealed the possible application of FeSe2/GO composite as a promising low-cost alternative to platinum based electrocatalysts for H2 production.

A series of imidazo-pyrimido fused acridines were synthesized and identified using conventional spectroscopic techniques. All the synthesized title compounds were subjected to in vitro antibacterial and insecticidal screenings. For insecticidal activity, the synthesized fused compounds are testing against two pests namely, Sitophilus oryzae (S. oryzae) and Callosobruchus maculatus (C. maculatus). For antibacterial screening, the compounds are testing against four bacteria, Bacillus subtilis (B. subtilis), Proteus mirabilis (P. mirabilis), Staphylococcus aureus (S. aureus) and Vibrio parahaemolyticus (V. parahaemolyticus). Notably, compound 8-(4-isopropylphenyl)-16-phenyl-6,7-dihydrobenzo[4′,5′]imidazo[1′,2′:1,2]pyrimido[4,5-a]acridine and 8-(2,4-dimethoxyphenyl)-16-phenyl-6,7-dihydrobenzo[4′,5′]imidazo[1′,2′:1,2]pyrimido[4,5-a]acridine were identified as the most promising applicant for further studies.

Ecofriendly synthesis of Palladium nanoparticles (PdNPs) were achieved using Phyllanthus emblica (P. emblica) seeds as reducing agent. Further the ecofriendly synthesized PdNPs were subjected for various analytical techniques like UV-Vis, FT-IR, XRD, Zeta potential, SEM and TEM. The results indicated that green synthesized PdNPs were spherical in shape with average particle size of 28±2nm with moderate stability. Further the synthesized PdNPs and extract were subjected for its antibacterial studies against various disease causing pathogens by agar well diffusion method. Seed extract resulted in 8.9±1.46mm against B. subtilis and PdNPs showed 9.6±1.10mm against S. aureus and synthesized PdNPs and extract were tested for hemolytic which resulted in 20% and 10% respectively. Toxicity studies were done against Artemia salina (A. salina). The LC50 value of green synthesized P. emblica capped PdNPs and the P. emblica seed extract were found to be less toxic for A. salina with a value of 1.00μg/mL and 1.25μg/mL. In addition samples were checked for in vitro cytotoxicity assays on HeLa cell lines.

In this era, researchers have mainly concentrated on green synthesis of nanoparticles which is rapid, nontoxic, ecofriendly, reproducible and less cost when compared to the chemical and physical methods. Phytochemical reduction of AgNO 3 to Ag NPs using root bark extracts of Catunaregum spinosa ( C . spinosa ) is reported in this manuscript. The resulting bio-reduced Silver nanoparticles (Ag NPs) were analyzed by UV–Visible Spectroscopy, FT-IR, XRD, TEM, Zeta potential and EDAX. Preparation of Ag NPs was identified by transformation of color from white to brown with maximum absorption at 442 nm due to Surface Plasmon Resonance. Crystalline studies by XRD inferred that the biosynthesized Ag NPs were crystalline in nature and further morphological studies revealed that the particles were spherically agglomerated with size ranging from 33 ± 2 nm. Moreover, the green synthesized Ag NPs were subjected for the degradation of toxic Amaranth dye using photoreactor exactly at 365 nm and pseudo first order kinetics were also stated the rate of degradation reaction were identified to be − K = 0.932 which provides significant results showing 94.07% degradation of azo grouped dye.

A new and highly efficient microwave promoted N -alkylation of triazolo-quinazolinones was developed by treating various phenyl-substituted heterocyclic amines with benzyl chloride using K 2 CO 3 as a base in the presence of DMF. Also the heterocyclic amines were synthesized by condensing the 3-amino-1,2,4-triazole substituted benzaldehydes and 1,3-cyclohexanedione in the presence of microwave irradiation under solvent free condition. The synthesized heterocycles 4a–o and 6a–o were further confirmed by using different spectroscopic techniques such as NMR and HRMS. The compounds 6a–o was studied for their solvatochromic property with increasing polarity of solvents. The determinations of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging effect of the scaffolds 6a–o were carried out by UV–Vis spectrometer. In terms of IC 50 all the compounds have shown remarkable antioxidant property compared with Ascorbic acid.

Pristine silver nanoparticles and silver-graphene oxide nanoparticles have incorporated in Bismuth doped manganese oxide (Bi-MnOx) nanotubes by an ultra-sonication deposition method. Pristine Bismuth doped porous MnO2 has prepared by a non-ionic surfactant (Triton-X-100) assisted co-precipitation and heat treatment process. In the second stage, the biogenic method prepared very fine Ag nanoparticles with a quantum dot size of particles (below 10 nm). They have further deposited on the dried powder of Bi-MnOx by ultra-sonication fabricate the composite material for electrode application. The pure nanotube formation obtained for silver nanoparticle deposited Bi-MnOx (Ag-BiMnOx) and silver/GO nanoparticle(Ag-BiMnOx/GO) nanocomposites have clearly confirmed by high resolution transmission electron micrographs (HR-TEM). The nanotube diameter obtained in the range of 10–25 nm and length of nanotube obtained in the rage of 40–50 nm. Enhanced thermal stability has achieved for Ag-BiMnOx and Ag-BiMnOx/GO composite compared to pristine manganese oxide. Band gap values of prepared compoiste is calculated from Diffuse reflectance spectral data provide the bandgap values of Ag–Bi-MnOx/GO (1.93 eV) and Bi-MnOx (2.47 eV). As prepared graphene oxide modified Bi-MnOx composite modified electrode have further analyzed for hydrogen peroxide sensor and Oxygen reduction reactions (ORR). Silver nanoparticle-graphene oxide modified Bi-MnOx composite shows an enhanced electrochemical capacitance activity of 2.61 mF and improved electrochemical surface area of 65.25 cm2 towards clean energy technology application.

Silver quantum dots particles (Ag QDs) and nanoparticles of Magnetite (Fe3O4) were deposited on nanotubes of Bismuth- insitu doped manganese oxide (Bi-MnOx) with porous morphologies via olymer assisted precipitation processes. The Ag QDs particles of very fine particle size and Fe3O4 nanoparticles were incorporated into the Bi-MnOx polymer composite via high power ultra-sonication deposition technique. Spherical nanoparticles of silver (5–15 nm) were deposited on the porous Bi-MnOx surfaces, whereas, in the case of the Fe3O4 which was deposited on Bi-MnOx nanotube composite in the form of nanorods, iron oxide particles were loaded into the tubular structure of the Bi-MnOx. The formation of nanotubes and the incorporation of nanorods were confirmed by the SEM and HR-TEM images. The diffuse reflectance spectra indicate a decrease in the bandgap of the composite after the incorporation of Fe3O4 nanoparticles into the Bi-MnOx nanotube . The nanoparticle-modified Bi-MnOx composite electrode was further characterized for hydrogen peroxide electrochemical sensor applications. Fast removal of toxic hexavalent chromium degradation reaction was carried out on the as-prepared Fe3O4- and Ag QDs particle-modified Bi-MnOx nanotube composites. An efficient sorption and removal of Cr (VI) (above 90% conversion) was achieved within 60 min of reaction on the Ag nanoparticle modfied Bi-MnOx. The results obtained show that the Ag@Bi-MnOx, and Fe3O4-modified porous Bi-MnOx nanotube composite materials demonstrated effective sensing and hexavalent chromium removal activity.

Herein, we demonstrate a covalent modification of hydrazine functionalized graphene oxide (FGO-H) using a protected tert-butyl carbazate (t-boc) as an intercalating agent over the GO surface and investigated as electrode candidates for electrochemical supercapacitor applications. The resulting functionalized materials were examined by different physicochemical techniques to investigate the physical and structural features of the as-made functionalized GO materials. The favorable method for the surface modification of GO is achieved by treating the primary amine of t-boc with the epoxide groups on the surface of GO. The FGO-TBpa electrode materials lead to the covalent coordinating moieties in between the basal planes of GO by enlargement of interlayer spacing of 1.8 nm from 0.9 nm. More importantly, the functionalized FGO-H can encourage the diffusion of electrolyte ion and result in the enhanced supercapacitance features. Notably, the FGO-H electrode has revealed a comparatively higher specific capacitance of 305 F g−1 at 1 A g−1 and showed excellent capacitance retention of 90%. The functionalized GO-based energy materials will have incredible impending applications in the energy-related systems.

A high temperature pyrolytic synthesis process was used to prepare N, S co-doped graphene/CNT-Fe3C composite materials. The optimization of heteroatom doping and its electrocatalytic performance towards H2O2 detection is significantly characterized and evaluated. The non-enzymatic hydrogen peroxide sensing is well catalyzed at NS-G/CNTFe-1 (10:1 weight ratio of melamine and thiourea) electrode with rapid response time and high cathodic current at −0.15 V (vs. Ag/AgCl), as compared to other modified electrodes. Chronoamperometry study reveals that the NS-G/CNTFe-1 electrode has a wide linear range with high selectivity and good operational stability.

Nanoparticles of metal chalcogenide (MoS2) are incorporated on reduced graphene oxide nano sheet rolled mesoporous manganese oxide were prepared by feasible ultrasonic assisted deposition technique. The above prepared nanocomposite is further coated on Nickel foam substrate for direct application towards high performance supercapcitor energy storage application. The detailed studies of surface and textural property such as crystalline phase stability, surface structure, particle size, zeta potential measurements have been explained for all prepared nanocomposite samples. The crystalline phase of as prepared mesoporous manganese oxide is forms the mixed phase of Mn2O3 bixbyite phase. The thermal stability of as prepared sample improved up to 400 °C in oxygen atmosphere and negative zeta potential obtained for all prepared nanocomposite sample. The different amount of MoS2 nanoparticle (10 mg −100 mg range) was utilized to study the effect of molybdenum sulphide (additive) addition on graphene oxide rolled mesoporous manganese oxide nanofiber matrix. Increased quantity of MoS2 addition increase the electrochemical supercapacitance value of the nanocomposite coated nickel foam based electrode. Nanofibers morphology of mesoporous manganese oxide with reduced graphene oxide is visibly seen in the TEM images. Needle like metallic rich shapes are also obtained due to MoS2 nanoparticle existence and it inserted in the Nanofiber/graphene sheet structure. The higher supercapacitance values are obtained for Nickel foam modified MoS2 deposited graphene oxide rolled MnOx nanocomposite (980 and 788 F/g) under acidic electrolyte medium and charge/discharge cycle stability have also been studied for all prepared nanocomposites.

Porous activated nanostructure carbon is prepared by feasible two steps method utilizing naturally available bio-wastes such as jack fruit peel waste (JFW) and studied the effect of pyrolysis condition for porosity formation. X-ray analysis and BET pore size analysis confirmed the formation of graphitic nature carbon with micro and mesoporous existence. HR-SEM and TEM images of Jack fruit (JF) derived porous carbon samples are shown spherical nanoball and tiny nanotube morphology. High resolution SEM images further confirms that the, increase in the activation temperature increase the uniform hexagon shape porous structure formation. The superior electrochemical activity and recycling stability was achieved for our method prepared (phohphoric acid activation method using graphite crucible mold) porous carbon materials. The Cs (specific capacitance) of the JF-9 (porous carbon prepared Jack fruit at 900 °C) sample was shown 324 F/g at the scan rate of 5 mV/s using Na2SO4 electrolyte. The JF carbon sample exhibits a higher capacitance retention of 93% for upto 5000 cycles. We found that the JF derived porous carbon sample shows higher recycling capacity by Galvano static charge-discharge analysis. The effect of current density and scan rate on specific capacitance property are analyzed in detailed by cyclic-voltammetry , Galvano static charge-discharge method and electrochemical impedance spectroscopy analysis.

Nickel-cobalt (Ni-Co) metal ion modified manganese oxide is prepared by a surfactant-assisted precipitation method through the in situ-doping into manganese oxide matrix. The prepared manganese oxide showed good porous property and improved surface area values and was further impregnated via reducing graphene oxide by an ultrasonication-assisted deposition method. The nanocomposite was decorated by adding commercial MoS2 nanoparticles to fabricate the binary nanocomposite. The thermal stability of the as-prepared sample was stable up to 450−500 °C in an air atmosphere and a negative zeta potential was obtained for most of the prepared nanocomposite sample. MoS2nanoparticle appeared as spherical nanoparticle at a smaller particle size formation (10−20 nm) on porous Ni-Co-MnOx surfaces, and nanoparticle deposition and graphene nanosheets act as a structure-directing agent toward layered nanotubes morphology formation for mesoporous manganese oxide. The as-prepared binary nanocomposite was further tested for toxic catalytic nitrophenol degradation under visible light exposure condition.

This work describes the effect of 2-aminopyrimidine (2-APY) on poly(vinylidinefluoride- co -hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) blend polymer electrolyte along with binary iodide salts (tetrabutylammonium iodide (TBAI) and potassium iodide (KI)) and iodine (I 2 ) were studied for enhancing the efficiency of the dye-sensitized solar cells (DSSCs) consisting of g-C 3 N 4 /TiO 2 composite as photoanode. The g-C 3 N 4 was synthesized from low cost urea by thermal condensation method. It was used as a precursor to synthesize the various weight percentage ratios (5%, 10% and 15%) of g-C 3 N 4 /TiO 2 composites by wet-impregnation method. The pure and 2-APY incorporated PVDF-HFP/PEO polymer blend electrolytes were arranged by wet chemical process (casting method) using DMF as a solvent. The synthesized g-C 3 N 4 /TiO 2 composites and polymer blend electrolytes were studied and analyzed by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The ionic conductivity values of the pure and 2-APY incorporated PVDF-HFP/PEO blend electrolytes were estimated to be 4.53×10 −5 and 1.87×10 −4 Scm −1 respectively. The UV–vis absorption spectroscopy was carried out for the pure and different wt% of g-C 3 N 4 /TiO 2 composites coated FTO films after N3 dye-sensitization. The 10 wt% g-C 3 N 4 /TiO 2 composite film showed a maximum absorption compared to the others. The DSSC assembled with 10 wt% g-C 3 N 4 /TiO 2 as photoanode using the pure polymer blend electrolyte exhibited a power conversion efficiency (PCE) of 3.17% , which was superior than that of DSSC based pure TiO 2 (2.46%). However, the PCE was increased to 4.73% for the DSSC assembled using 10 wt% g-C 3 N 4 /TiO 2 as photoanode with 2-APY incorporated polymer blend electrolyte. Hence, the present study is a successful attempt to provide a new pathway to enhance the performance of DSSCs.

Active, stable and economical electro-catalysts are very necessary for hydrogen production through water splitting by electrolysis. This work reports the synthesis and characterization of highly porous cobalt hydroxide (meso-Co-OH) formed by a simple chemical precipitation within the interstitial space of liquid crystal template. The physicochemical properties of the meso-Co-OH were characterized by surface area analyzer, X-ray diffraction, XPS, scanning and transmission electron microscopes. The meso-Co-OH exhibits low crystallinity and high surface area of 457 ± 5 m2/g with a mesoporous structure and pore diameter of 4.0 ± 1.0 nm. As confirmed by the electrochemical characterizations, the meso-Co-OH is highly effective electro-catalyst for oxygen evolution reaction (OER) at low applied potential and shows superior activity and stability than iridium oxide during long term water electrolysis in alkaline media. The meso-Co-OH shows oxygen evolution current and onset potential comparable to the IrO2 catalyst and the current is enhanced by 10 times than the values of bulk cobalt hydroxide electrode. For meso-Co-OH catalyst the oxygen evolution overpotential of 1.55 V (vs. RHE) at current density of 25 mA cm2 has been achieved in 1.0 M KOH. The enhanced OER activity was attributed to the substantial increase in the active catalyst surface area due to the formation of mesoporous network within the cobalt hydroxide framework.

Lanthanum tantalum niobium oxynitride [La(Ta,Nb)O2N] powders were prepared with different Nb/Ta ratios by conventional solid state reaction. La(Ta,Nb)O2N photoanodes were fabricated by electrophoretic deposition of La(Ta,Nb)O2N suspension in acetone onto ITO substrate. The La(Ta,Nb)O2N photoanodes were found to exhibit photoelectrochemical activity for water oxidation reaction in alkaline solution. Subsequently, a cobalt-phosphate based oxygen evolution catalyst (CoPi-OEC) was photodeposited onto the surface of the La(Ta,Nb)O2N catalyst to improve the photoelectrochemical performance. In the presence of CoPi catalyst, the photocurrent-voltage characteristics of the La(Ta,Nb)O2N electrodes were enhanced with its effect more pronounced at lower potentials. A stable photocurrent density of 20 mA/cm2 at 1.2 V vs SCE was achieved under the illumination using alkaline phosphate solution with pH 13. Relative to the La(Ta,Nb)O2N photoanodes, nearly three times higher photocurrent density was observed at 1.2 V vs SCE for a CoPi/La(Ta,Nb)O2N photoelectrode. Perovskite-based oxide-nitrides modified with suitable cocatalyst of CoPi, have been shown as a new pathway towards substantial photoelectrochemical current gain during the PEC water splitting reaction.

The rapid advancement of the global industry has led to energy shortage and environmental pollution. To mitigate against these issues, researchers and scientists are developing simple and efficient techniques. Among these, semiconductor photocatalysis has gained widespread attention as a pivotal solution to energy scarcity and environmental protection. The specific surface area (SSA), band gap energy, and morphology of the materials are the key factors for photocatalysis, and it influences the photocatalytic property. Irradiation of photocatalysts generates holes and electrons. Holes are present in the valence band (VB,) and they undergo oxidation reaction to produce hydroxyl radicals (.OH). Electrons in the conduction band go through a reduction process, and they react with oxygen in the air to produce superoxide radical anions (O2−.). These active radicals degrade the toxic organic compounds to produce H2O and CO2. Several approaches have been utilized to improve the photocatalytic activity of visible light photocatalysts. They include doping, structural control, phase transfer, band gap regulation, and surface sensitization. The major characteristics of efficient photocatalysts include non-toxicity, photoactivity, and inertness to chemical and biological matters, photostability, ability to absorb near UV/visible regions, and cost-effectiveness. Herein, major semiconductor photocatalytic materials, namely, TiO2, ZnO, WO3, SiC, CuO, CdS, PbS, and SnO2, are elaborately discussed. Most of the recent advances in photocatalysis, as well as properties and applications of the photocatalytic materials are also discussed.

Nanosized tungsten-cobalt oxide (WCoO-NP) electrodes were prepared using self-assembly template approach and their bifunctional electrocatalytic behaviour for the oxygen redox reactions was investigated. The texture, morphology, specific surface area, crystallinity, and electrocatalytic activity of the WCoO-NP were strongly associated with the W and Co content. The WCoO-NP materials contains 15 mol% of tungsten showed enhanced electrocatalytic behaviour, substantial shift in the OER onset potential of 190 mV, Tafel slope (92 mV/dec), ultra-low charge-transfer resistance, and current density of 30 mA cm−2 at 1.55 VRHE, which is more efficient catalyst than bare cobalt oxide nanoparticles (Co3O4-NP) counterpart and comparable to benchmark transition metal oxide electrocatalysts. The WCoO-NP materials exhibits long-term durability and good bifunctional electrocatalytic behaviour for both the OER and ORR, having ΔE (=EOER − EORR) of only 0.92 V which could be credited to the synergistic effect, enriched specific surface area, and improved electrical conductivity upon tungsten-doping. The WCoO-NP electrocatalysts prepared from earth-abundant materials are a promising candidate for high-efficiency OER and ORR applications.

Herein, we have examined the photocatalytic activity (PCA) of as-prepared BiFeWO6/ZnO nanocomposites for Rhodamine-B (RhB) degradation under visible-light irradiation (VLI). A simple co-precipitation process was preferred to fabricate both bare ZnO and BiFeWO6. The BiFeWO6/ZnO nanocomposites were fabricated by adding the various amounts (1, 5 and 10 wt%) of BiFeWO6 into ZnO via the wet-impregnation process. Among various nanocomposites, the 5 %-BiFeWO6/ZnO nanocomposite displayed an excellent PCA for RhB degradation, which was ∼2 folds higher than the bare ZnO. The as-prepared nanocomposites were examined by Fourier transform-infrared (FTIR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), UV–vis diffuse reflection spectroscopy (DRS), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and photo-electrochemical studies. Finally, a feasible RhB degradation mechanism was offered over BiFeWO6/ZnO nanocomposites under VLI.