Anion selective <i>p</i>TSA doped polyaniline@graphene oxide-multiwalled carbon nanotube composite for Cr(VI) and Congo red adsorption

Ansari, Mohammad Omaish,Kumar, Rajeev,Ansari, Sajid Ali,Ansari, Shahid Pervez,Barakat, M.A.,Alshahrie, Ahmed,Cho, Moo Hwan Elsevier 2017 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.496 No.-

<P><B>Abstract</B></P> <P>Multiwalled carbon nanotube (CNT)-graphene oxide (GO) composite was combined with polyaniline (Pani) using an oxidative polymerisation technique. The resulting Pani@GO-CNT was later doped with para toluene sulphonic acid (<I>p</I>TSA) to generate additional functionality. The functional groups exposed on the GO, Pani and <I>p</I>TSA were expected to impart a high degree of functionality to the <I>p</I>TSA-Pani@GO-CNT composite system. The composite was characterised by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The characterisation results revealed the characteristics of Pani, GO, CNT, and <I>p</I>TSA, and suggested the successful formation of the <I>p</I>TSA-Pani@GO-CNT composite system. The composite was utilised successfully for the adsorptive removal of Cr(IV) and Congo red (CR) dye and the adsorption of both pollutants was found to be strongly dependent on the solution pH, adsorbate concentration, contact time, and reaction temperature. The maximum adsorption of Cr(IV) and CR was observed in an acidic medium at 30°C. The kinetics for Cr(IV) and CR adsorption was studied using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The adsorption equilibrium data were also fitted to the Langmuir and Freundlich isotherm models. The thermodynamic results showed that the adsorption process was exothermic in nature. The present study provides a new methodology for the preparation of a highly functionalised Pani-based nanocomposite system and its potential applications to the adsorptive removal of a multicomponent pollutant system from an aqueous solution.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Gold nanoparticles-sensitized wide and narrow band gap TiO₂ for visible light applications: a comparative study

Ansari, Sajid Ali,Khan, Mohammad Mansoob,Ansari, Mohd Omaish,Cho, Moo Hwan The Royal Society of Chemistry 2015 NEW JOURNAL OF CHEMISTRY Vol.39 No.6

<P>Gold nanoparticles (AuNPs)-sensitized wide band gap TiO<SUB>2</SUB> (Au/P-TiO<SUB>2</SUB>) and narrow band gap TiO<SUB>2</SUB> (Au/M-TiO<SUB>2</SUB>) nanocomposites were prepared using an electrochemically active biofilm. The optical and structural properties of the Au/P-TiO<SUB>2</SUB> and Au/M-TiO<SUB>2</SUB> nanocomposites were characterized using standard techniques. The surface plasmon resonance (SPR) absorption characteristics of the AuNPs on the TiO<SUB>2</SUB> surface extended the absorption edge of P-TiO<SUB>2</SUB> and M-TiO<SUB>2</SUB> to the visible light region. The photocatalytic activity of the Au/P-TiO<SUB>2</SUB> and Au/M-TiO<SUB>2</SUB> nanocomposites was evaluated by the photodegradation of methylene blue and methyl orange, and 2-chlorophenol under visible light irradiation, where Au/M-TiO<SUB>2</SUB> nanocomposite exhibited enhanced photocatalytic activity compared to the Au/P-TiO<SUB>2</SUB> nanocomposite and P-TiO<SUB>2</SUB> and M-TiO<SUB>2</SUB> nanoparticles. Furthermore, the higher photoelectrochemical performance of the Au/M-TiO<SUB>2</SUB> nanocomposite compared to the Au/P-TiO<SUB>2</SUB> nanocomposite and P-TiO<SUB>2</SUB> and M-TiO<SUB>2</SUB> nanoparticles further support its higher visible light active behavior under visible light irradiation. The pronounced photoactivities of the Au/M-TiO<SUB>2</SUB> nanocomposite in the visible region were attributed to the interfacial synergistic effects of the two phenomena, <I>i.e.</I> the SPR effect of AuNPs and the defect-induced band gap reduction of M-TiO<SUB>2</SUB> nanoparticles. The present work provides a newer insight into the development of nanocomposites of noble metals and defective metal oxides with high efficiency in the field of visible light-induced photoactivity.</P> <P>Graphic Abstract</P><P>Photocatalytic degradation of dyes and organic compounds by Au/P-TiO<SUB>2</SUB> and Au/M-TiO<SUB>2</SUB> nanocomposites under visible light irradiation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5nj00556f'> </P>

Highly photoactive SnO₂ nanostructures engineered by electrochemically active biofilm

Ansari, Sajid Ali,Khan, Mohammad Mansoob,Omaish Ansari, Mohd,Lee, Jintae,Cho, Moo Hwan The Royal Society of Chemistry 2014 NEW JOURNAL OF CHEMISTRY Vol.38 No.6

<P>This paper reports the defect-induced band gap narrowing of pure SnO<SUB>2</SUB> nanostructures (p-SnO<SUB>2</SUB>) using an electrochemically active biofilm (EAB). The proposed approach is biogenic, simple and green. The systematic characterization of the modified SnO<SUB>2</SUB> nanostructures (m-SnO<SUB>2</SUB>) revealed EAB-mediated defects in the pure SnO<SUB>2</SUB> nanostructures (p-SnO<SUB>2</SUB>). The modified SnO<SUB>2</SUB> (m-SnO<SUB>2</SUB>) nanostructures in visible light showed the enhanced photocatalytic degradation of <I>p</I>-nitrophenol and methylene blue compared to the p-SnO<SUB>2</SUB> nanostructures. The photoelectrochemical studies, such as the electrochemical impedance spectroscopy and linear scan voltammetry, also revealed a significant increase in the visible light response of the m-SnO<SUB>2</SUB> compared to the p-SnO<SUB>2</SUB> nanostructures. The enhanced activities of the m-SnO<SUB>2</SUB> in visible light was attributed to the high separation efficiency of the photoinduced electron–hole pairs due to surface defects mediated by an EAB, resulting in a band gap narrowing of the m-SnO<SUB>2</SUB> nanostructures. The tuned band gap of the m-SnO<SUB>2</SUB> nanostructures enables the harvesting of visible light to exploit the properties of the metal oxide towards photodegradation, which can in turn be used for environmental remediation applications.</P> <P>Graphic Abstract</P><P>This paper reports the defect-induced band gap narrowing of pure SnO<SUB>2</SUB> nanostructures (p-SnO<SUB>2</SUB>) using an electrochemically active biofilm (EAB). <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3nj01488f'> </P>

Enhanced Thermal Stability under DC Electrical Conductivity Retention and Visible Light Activity of Ag/TiO₂@Polyaniline Nanocomposite Film

Ansari, Mohd Omaish,Khan, Mohammad Mansoob,Ansari, Sajid Ali,Raju, Kati,Lee, Jintae,Cho, Moo Hwan American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.11

<P>The development of organic–inorganic photoactive materials has resulted in significant advancements in heterogeneous visible light photocatalysis. This paper reports the synthesis of visible light-active Ag/TiO<SUB>2</SUB>@Pani nanocomposite film via a simple biogenic–chemical route. Electrically conducting Ag/TiO<SUB>2</SUB>@Pani nanocomposites were prepared by incorporating Ag/TiO<SUB>2</SUB> in <I>N</I>-methyl-2-pyrrolidone solution of polyaniline (Pani), followed by the preparation of Ag/TiO<SUB>2</SUB>@Pani nanocomposite film using solution casting technique. The synthesized Ag/TiO<SUB>2</SUB>@Pani nanocomposite was confirmed by UV–visible spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Ag/TiO<SUB>2</SUB>@Pani nanocomposite film showed superior activity towards the photodegradation of methylene blue under visible light compared to Pani film, even after repeated use. Studies on the thermoelectrical behavior by DC electrical conductivity retention under cyclic aging techniques showed that the Ag/TiO<SUB>2</SUB>@Pani nanocomposite film possessed a high combination of electrical conductivity and thermal stability. Because of its better thermoelectric performance and photodegradation properties, such materials might be a suitable advancement in the field of smart materials in near future.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-11/am500488e/production/images/medium/am-2014-00488e_0013.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am500488e'>ACS Electronic Supporting Info</A></P>

Electrically conductive polyaniline sensitized defective-TiO₂ for improved visible light photocatalytic and photoelectrochemical performance: a synergistic effect

Ansari, Mohd Omaish,Khan, Mohammad Mansoob,Ansari, Sajid Ali,Cho, Moo Hwan The Royal Society of Chemistry 2015 NEW JOURNAL OF CHEMISTRY Vol.39 No.11

<P>Sulfonated polyaniline@pure-TiO<SUB>2</SUB> (s-Pani@p-TiO<SUB>2</SUB>) and polyaniline@defective-TiO<SUB>2</SUB> (s-Pani@m-TiO<SUB>2</SUB>) nanocomposites were prepared by the <I>in situ</I> oxidative polymerization of aniline in the presence of TiO<SUB>2</SUB> (p-TiO<SUB>2</SUB> and m-TiO<SUB>2</SUB>) nanoparticles followed by sulfonation with fuming sulfuric acid. Defect-induced TiO<SUB>2</SUB> (m-TiO<SUB>2</SUB>) nanoparticles were obtained by an electron beam (EB) treatment of commercial TiO<SUB>2</SUB> (p-TiO<SUB>2</SUB>) nanoparticles. The resulting s-Pani@p-TiO<SUB>2</SUB> and s-Pani@m-TiO<SUB>2</SUB> nanocomposites were characterized by UV-visible diffuse absorbance spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Polyaniline (Pani) was dispersed uniformly over the defective m-TiO<SUB>2</SUB> surface with intimate contact on the interface to act cooperatively with the deliberately induced defects to achieve remarkably enhanced properties. The s-Pani@m-TiO<SUB>2</SUB> nanocomposite showed better photocatalytic activity and photoelectrochemical performance than s-Pani@p-TiO<SUB>2</SUB> under visible light irradiation, which was attributed partly to the sensitizing effect of Pani, the narrowed band gap of m-TiO<SUB>2</SUB> and the effective interfacial interaction between Pani and m-TiO<SUB>2</SUB>. The electrical conductivity measured using a four-point probe revealed s-Pani@m-TiO<SUB>2</SUB> to have much higher conductivity than s-Pani@p-TiO<SUB>2</SUB>. Therefore, s-Pani@m-TiO<SUB>2</SUB> may be used for a wide range of applications owing to its higher charge mobility and high photocatalytic activity. The proposed methodology can also be a potential route for the development of nanocomposites <I>via</I> EB treatment and can be commercialized.</P> <P>Graphic Abstract</P><P>A proposed scheme for the synthesis of s-Pani@m-TiO<SUB>2</SUB> nanocomposites. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5nj01127b'> </P>

Fibrous polyaniline@manganese oxide nanocomposites as supercapacitor electrode materials and cathode catalysts for improved power production in microbial fuel cells

Ansari, Sajid Ali,Parveen, Nazish,Han, Thi Hiep,Ansari, Mohammad Omaish,Cho, Moo Hwan The Royal Society of Chemistry 2016 Physical chemistry chemical physics Vol.18 No.13

<P>Fibrous Pani-MnO2 nanocomposite were prepared using a one-step and scalable in situ chemical oxidative polymerization method. The formation, structural and morphological properties were investigated using a range of characterization techniques. The electrochemical capacitive behavior of the fibrous Pani-MnO2 nanocomposite was examined by cyclic voltammetry and galvanostatic charge-discharge measurements using a three-electrode experimental setup in an aqueous electrolyte. The fibrous Pani-MnO2 nanocomposite achieved high capacitance (525 F g(-1) at a current density of 2 A g(-1)) and excellent cycling stability of 76.9% after 1000 cycles at 10 A g(-1). Furthermore, the microbial fuel cell constructed with the fibrous Pani-MnO2 cathode catalyst showed an improved power density of 0.0588 W m(-2), which was higher than that of pure Pani and carbon paper, respectively. The improved electrochemical supercapacitive performance and cathode catalyst performance in microbial fuel cells were attributed mainly to the synergistic effect of Pani and MnO2 in fibrous Pani-MnO2, which provides high surface area for the electrode/electrolyte contact as well as electronic conductive channels and exhibits pseudocapacitance behavior.</P>

Route to High Surface Area, Mesoporosity of Polyaniline–Titanium Dioxide Nanocomposites via One Pot Synthesis for Energy Storage Applications

Parveen, Nazish,Ansari, Mohd Omaish,Cho, Moo Hwan American Chemical Society 2016 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.55 No.1

<P>This paper reports the synthesis of mesoporous polyaniline-titanium dioxide (Pani-TiO2) nanocomposites via a one pot approach in the presence of aniline and titanium iso-propoxide precursor under ice bath conditions. Scanning and transmission electron microscopy showed that the Pani-TiO2 was mesoporous in nature. BET analysis revealed the Pani-TiO2 to have a 2-fold higher surface area than Pani. The shift of the peaks in the FTIR and XRD pattern showed that TiO2 had perfectly intercalated into the Pani matrix, which suggests a strong interaction between Pani and TiO2. The electrochemical properties of Path and the mesoporous Pani-TiO2 were examined by cyclic voltammetry and charge/discharge studies. The mesoporous Pani-TiO2 electrode exhibited a high specific capacitance of 935 F g(-1) at 1 A g(-1) current density. The mesoporous Pani-TiO2 displayed excellent cyclic stability up to 2000 cycles and delivered a high energy density of 94.8 Wh kg(-1) at a 977 W kg(-1) power density.</P>

Manganese dioxide nanorods intercalated reduced graphene oxide nanocomposite toward high performance electrochemical supercapacitive electrode materials

Parveen, Nazish,Ansari, Sajid Ali,Ansari, Mohammad Omaish,Cho, Moo Hwan Elsevier 2017 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.506 No.-

<P><B>Abstract</B></P> <P>The development of manganese dioxide-based nanocomposites as materials for energy storage applications is advantageous because of its polymorphism behavior and structural flexibility. In this study, manganese dioxide (MnO<SUB>2</SUB>) nanorod-intercalated reduced graphene oxide (rGO) nanocomposite was obtained through a simple hydrothermal method and their electrochemical supercapacitance was studied in a three electrode half-assembly electrochemical cell. The basic spectroscopic and diffraction data including Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were employed to characterize the resulting nanocomposite. Cyclic voltammetry and galvanostatic charge-discharge measurements were conducted to evaluate the electrochemical supercapacitance of the rGO-MnO<SUB>2</SUB> nanocomposite electrode. The rGO-MnO<SUB>2</SUB> nanocomposite delivered significantly higher capacitance than the P-MnO<SUB>2</SUB> under similar measurement conditions. This enhanced supercapacitive performance of the rGO-MnO<SUB>2</SUB> nanocomposite was attributed to chemical interactions and the synergistic effect between rGO and MnO<SUB>2</SUB>, which was helpful in enhancing the electrical conductivity and providing sufficient space for electrode/electrolyte contact during the electrochemical reaction.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Simultaneous sulfur doping and exfoliation of graphene from graphite using an electrochemical method for supercapacitor electrode materials

Parveen, Nazish,Ansari, Mohd Omaish,Ansari, Sajid Ali,Cho, Moo Hwan The Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.1

<▼1><P>Doping with heteroatoms has become a significant strategy for modifying the electronic properties and enhancing the electrochemical properties of graphene (GN).</P></▼1><▼2><P>Doping with heteroatoms has become a significant strategy for modifying the electronic properties and enhancing the electrochemical properties of graphene (GN). In this study, an environmental friendly, economical and facile one pot electrochemical method was developed to synthesize sulfur-doped graphene (S-GN). Sodium thiosulphate (Na2S2O3), in addition to acting as a sulfur source, also catalyzed the exfoliation process, resulting in sulfur-doped GN structures. The exfoliation of graphite to GN and sulfur (S) doping occurred simultaneously resulting in well dispersed S-GN frameworks. Transmission electron microscopy and high-resolution transmission electron microscopy revealed the presence of the heteroatom in S-GN, and X-ray photoelectron spectroscopy confirmed the high S content (3.47%), as well as the existence of high-quality sulphureted species (mainly as C–S–C–). The incorporation of S species in GN during the exfoliation process modified the surface chemistry of carbon in the GN. The electrochemical performance of the as-prepared S-GN electrode exhibited a high specific capacitance of 320 F g<SUP>−1</SUP> at a current density of 3 A g<SUP>−1</SUP> and excellent cycling stability up to 1500 cycles as well as high energy density of 160 W h kg<SUP>−1</SUP> at a power density of 5161 W kg<SUP>−1</SUP> in an aqueous electrolyte.</P></▼2>

High Performance Supercapacitor Applications and DC Electrical Conductivity Retention on Surfactant Immobilized Macroporous Ternary Polypyrrole/Graphitic‑C3N4@Graphene Nanocomposite

Ahmed Alshahrie,Mohammad Omaish Ansari 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.2

Electrically conductive conducting polymer nanocomposites with carbonaceous materials have attraction the attentionworldwide in resolving the energy crisis for economic reasons, ease of fabrication and easily controllable variable redoxchemical states. In this work, highly conducting polypyrrole/g-C 3 N 4 @graphene (PPy/g-C 3 N 4 @GN) has been fabricatedby polymerizing pyrrole with g-C 3 N 4 along with surfactant para toluene sulfonic acid ( p TSA) and later incorporating itwith GN by hydrothermal methodology to form a macroporous network of p TSA doped PPy/g-C 3 N 4 @GN. Thus preparedPPy/g-C 3 N 4 @GN composite was characterized for the morphological characterizations by scanning electron microscopy,transmission electron microscopy while the structural characterizations were done by X-ray powder diff raction and X-rayphotoelectron spectroscopy. The morphological analysis showed that the PPy and g-C 3 N 4 were well distributed inside theGN sheets thereby forming structures of high porosity. The PPy and g-C 3 N 4 were sandwiched between the sheets of GN andsuch morphology is expected to promote the electron transfer. The PPy/g-C 3 N 4 @GN composite showed high conductivityof 8.8 S/cm and exceptionally high thermal stability in aging thermal conductivity experiments. The high conductivity andstability is attributed to the contribution of following factors i.e. the high stability of g-C 3 N 4 , high conductivity of GN andPPy. Three electrode assembly was used to study the electrochemical supercapacitive characteristics; cyclic voltammetriccurves and galvanostatic charge discharge measurements of PPy/g-C 3 N 4 @GN. The obtained nanocomposite delivered highcapacitance of 260.4 F g −1 at a current load of 1 A g −1 as well as excellent 80% cyclic stability after the continuous 2000charge discharge cycles. The enhanced performance is due the interaction between all the constituents in the present nanocompositesand improved electrical conductivity.