Polyaniline Catalyst Research Articles

CO 2 electroreduction to acetate by enhanced tandem effects of surface intermediate over Co 3O 4 supported polyaniline catalyst

CO ₂ electroreduction to acetate by enhanced tandem effects of surface intermediate over Co ₃O ₄ supported polyaniline catalyst

Selective electrooxidation of 5-hydroxymethylfurfural to 5-formyl-furan-2-formic acid on non-metallic polyaniline catalysts: structure-function relationships.

The biomass-derived HMF oxidation reaction (HMFOR) holds great promise for sustainable production of fine chemicals. However, selective electrooxidation of HMF to high value-added intermediate product 5-formyl-furan-2-formic acid (FFCA) is still challenging. Herein, we report the electrocatalytic HMFOR to selectively produce FFCA using carbon paper (CP) supported polyaniline (PANI) as a catalyst. The PANI/CP non-metallic hybrid catalyst with moderate oxidation capacity exhibitsoptimized FFCA selectivity up to 76% in alkaline media, which has reached the best performance in reported literature studies. Identification and quantification of active sites for the HMFOR are further realized via linking the activity to structural compositions of PANI; both polaronic-type nitrogen (N3) and positively charged nitrogen (N4) species are proved responsible for adsorption and activation of HMF, and the intrinsic activity of N4 is higher than that of N3. The present work provides new physical-chemical insights into the mechanism of the HMFOR on non-metallic catalysts, paving the way for the establishment of structure-function relations and further development of novel electrochemical synthesis systems.

A new approach for ammonia gas sensing using a source pocket dopingless tunnel FET with PANI catalyst

This article presents a new ammonia (NH3) gas sensor designed using a dopingless tunnel field effect transistor with a SiGe source pocket (SP-DLT) and investigates its sensitivity using a polyaniline (PANI) conducting polymer as the gate catalyst. PANI nanofiber has a greater specific surface area and a linked network structure, which increases its sensing performance as a catalyst. Combining an HfO2 gate dielectric and SiGe source pocket improves the drain current. The sensing film is deprotonated when the PANI conducting polymer is exposed to the gas, reducing the film’s resistance. As a result, more electron or proton transfer is possible, ensuring a more substantial interaction between the sensor and the analyte gas. This modulates the electrical characteristics and work function of the TFET. The sensor’s electrical performance is examined in terms of drain current, average subthreshold swing (SS), electric field, band-to-band tunneling rate (BTBT), and energy band diagram for an ammonia gas pressure (AGP) range of 10−12 torr to 10−9 torr. The sensitivity and selectivity of the proposed PANI-SP-DLT sensor in terms of different metrics, including drain current, average SS, current ratio, transconductance, and gain factor, are further investigated. The study is expanded to consider the impact of temperature affectability and the germanium mole fraction on current sensitivity performance. The Silvaco ATLAS device simulator is used for the brief simulation work for the developed gas sensor.

Template‐Oriented Polyaniline‐Supported Palladium Nanoclusters for Reductive Homocoupling of Furfural Derivatives

AbstractDeveloping well‐defined structures and desired properties for porous organic polymer (POP) supported catalysts by controlling their composition, size, and morphology is of great significance. Herein, we report a preparation of polyaniline (PANI) supported Pd nanoparticles (NPs) with controllable structure and morphology. The protocol involves the introduction of MnO2 with different crystal structures (α, β, γ, δ, ϵ) serving as both the reaction template and the oxidant. The different forms of MnO2 each convert aniline to a PANI that contains a unique regular distribution of benzene and quinone. This leads to the Pd/PANI catalysts with different charge transfer properties between Pd and PANI, as well as different dispersions of the metal NPs. In this case, the Pd/ϵ‐PANI catalyst greatly improves the turnover frequency (TOF; to 88.3 h−1), in the reductive coupling of furfural derivatives to potential bio‐based plasticizers. Systematic characterizations reveal the unique oxidation state of the support in the Pd/ϵ‐PANI catalyst and coordination mode of Pd that drives the formation of highly dispersed Pd nanoclusters. Density functional theory (DFT) calculations show the more electron rich Pd/PANI catalyst has the lower energy barrier in the oxidative addition step, which favors the C−C coupling reaction.

Bismuth Vanadate Decked Polyaniline Polymeric Nanocomposites: The Robust Photocatalytic Destruction of Microbial and Chemical Toxicants.

Functional materials have long been studied for a variety of environmental applications, resource rescue, and many other conceivable applications. The present study reports on the synthesis of bismuth vanadate (BiVO4) integrated polyaniline (PANI) using the hydrothermal method. The topology of BiVO4 decked PANI catalysts was investigated by SEM and TEM. XRD, EDX, FT-IR, and antibacterial testing were used to examine the physicochemical and antibacterial properties of the samples, respectively. Microscopic images revealed that BiVO4@PANI are comprised of BiVO4 hollow cages made up of nanobeads that are uniformly dispersed across PANI tubes. The PL results confirm that the composite has the lowest electron-hole recombination compared to others samples. BiVO4@PANI composite photocatalysts demonstrated the maximum degradation efficiency compared to pure BiVO4 and PANI for rhodamine B dye. The probable antimicrobial and photocatalytic mechanisms of the BiVO4@PANI photocatalyst were proposed. The enhanced antibacterial and photocatalytic activity could be attributed to the high surface area and combined impact of PANI and BiVO4, which promoted the migration efficiency of photo-generated electron holes. These findings open up ways for the potential use of BiVO4@PANI in industries, environmental remediation, pharmaceutical and medical sectors. Nevertheless, biocompatibility for human tissues should be thoroughly examined to lead to future improvements in photocatalytic performance and increase antibacterial efficacy.

Fe Single-Atom Catalyst for Cost-Effective yet Highly Efficient Heterogeneous Fenton Catalysis.

High energy consumption in pyrolyzing precursors for catalyst preparation would limit the application of nitrogen-doped carbon-based single-atom catalysts in actual pollutant remediation. Herein, we report an Fe single atom (7.67 wt %) loaded polyaniline catalyst (Fe-PANI) prepared via a simple impregnation process without pyrolysis. Both experimental characterizations and density functional theory calculations demonstrated that isolated -N═ group sites can fasten Fe atoms through Fe-N coordination in PANI, leading to a high stability of Fe atoms in a heterogeneous Fenton reaction. Highly dispersive yet dense -N═ groups in PANI can be protonated to be adsorption sites, which largely reduce the migration distance between reactive radicals and organics. More significantly, frontier molecular orbitals and spin-density distributions reveal that electrons can transfer from reduction groups of PANI to an Fe(III) site to accelerate its reduction. As a result, a remarkably boosted degradation behavior of organics under near-neutral conditions (pH 6), with low H2O2 concentration, was achieved. This cost-effective Fe-PANI catalyst with high catalytic activity, stability, and adsorption performance has great potential for industrial-level wastewater treatment.

Electrodeposition of Metal‐Free Polyaniline Electrocatalyst for Efficient Oxygen Evolution in Acid

AbstractDeveloping efficient and competitive electrocatalysts for the oxygen evolution reaction (OER) in acid is a great challenge for hydrogen production. Compared with metal catalysts, metal‐free catalysts are more environmentally friendly and cheaper. Herein, we present a novel non‐metallic self‐supporting polyaniline catalyst (PANI3/CFP) synthesized by electrodeposition for efficient water oxidation. Benefiting from the three‐dimensional network structure, excellent conductivity, and large number of nitrogen functional groups, PANI3/CFP exhibits high activity towards OER. At a current density of 10 mA cm−2, PANI3/CFP delivers a low overpotential of 204 mV in 0.1 mHClO4, much lower than commercial Ir/C and previously reported acidic OER catalysts. Besides, the turnover frequency (TOF) value of PANI3/CFP reaches 0.0456 s−1at 1.5 V versus the reversible hydrogen electrode (vs. RHE). Analysis of structure and electrocatalytic performances reveal that =N− species in polyaniline are the main active sites for acidic OER. This work provides a unique strategy for the design of non‐metallic acidic OER catalysts.

Electrochemical studies and electrocatalytic applications of Zirconia-Polyaniline nanocomposite

• Ethanol and formic acid oxidation. • Electrocatalyst. • polyaniline/ZrO 2 nanocomposite. In recent days, conducting polymers with inorganic metal oxide shows interest in electrochemical and electro catalytic applications. Zirconia doped polyaniline (PANI) nanocomposites were synthesized through in situ polymerization method for both formic acid oxidation (FAO) and ethanol oxidation reaction (EOR). The synthesized nanocomposites were characterized by X-ray Diffraction Spectroscopy (XRD), High-Resolution Transmission Electron Microscope (HRTEM), Energy Dispersive Spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of nanocomposites were tested by cyclic voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) methods. Studies of differential Pulse Voltammetry and chronoamperometry shows the electro catalytic activity and stability of the ZrO 2 -PANI catalyst. The FAO of ZrO 2 -PANI demonstrates the highest electro catalytic performance with a high current density of 4.6 mA.cm −2 , which is higher than the EOR with the maximum of peak current of 2.8 mA.cm −2 . As per studies, ZrO 2 -PANI nanocomposites work well as a direct-formic acid fuel cell electrocatalyst.

Polyaniline mediated heterogeneous catalysis in the preparation of heterocyclic derivatives through carbon–heteroatom bond formations

Abstract Green-bond forming reactions in organic chemistry are very much essential for the sustainability and it is a continuous evolutionary process. Polyaniline (PANI) is one of the catalysts can offer a green-bond forming chemistry. The present chapter is designed to explain PANI mediated reactions leading to the synthesis of heterocycles. PANI and PANI-doped catalyst preparation methods and together with characterization of PANI catalyst using modern analytical tools is explained. Several heterocycles were prepared using PANI or doped-PANI catalyst in a one pot reaction conditions or sometimes multicomponent reaction conditions. Ease of PANI preparation, simple reaction conditions, PANI recovery and reusability and quick-way of product isolation or workup procedure are the highlights of this chapter.

Preparation supported heteropoly (acid)/polyaniline catalysts and catalytic synthesis of tributyl citrate.

A series of polyaniline supported heteropoly acids were prepared through a simple method at room temperature. The obtained heterogeneous catalysts were comprehensively characterized by powder FTIR spectroscopy, UV-vis spectra, NH3 temperature programmed desorption (TPD) and scanning electron microscopy (SEM). The influence of various process parameters such as heteropoly loading (10 to 25 wt%), catalyst amount (3–5%), molar ratio of n-butanol to citric acid (3 to 5), and reaction time (3.5–12 h) have been investigated over heteropoly/polyaniline catalysts with the aim to maximize citric acid conversion and tributyl citrate selectivity. The different catalytic tests has shown that the catalyst exhibits high conversion and selectivity by using the as-prepared heteropoly/polyaniline catalysts for esterification under appropriate conditions. The present method of using 20% heteropoly/polyaniline catalyst for the synthesis of tributyl citrate would be environmentally benign in the reusability of catalyst.

A Simple and Reusable Polyaniline Catalyst for the Ring-opening Polymerization of Tetrahydrofuran

A Simple and Reusable Polyaniline Catalyst for the Ring-opening Polymerization of Tetrahydrofuran

Sonochemical Synthesis of Platinum Catalysts Supported on Carbonized Polyaniline for Proton Exchange Membrane Fuel Cell

Carbon supported catalysts usually have high catalytic efficiency due to a low metal loading and large surface area. Thus the platinum catalyst loaded on the carbon black has been widely used for PEMFC(proton exchange membrane fuel cell), and it makes enormous development possible in the field of fuel cell. The methods used for making platinum catalyst loaded on carbon could be divided into two categories. One is to reduce metal precursor by mixing it with supporting material, and the other is to mix supporting materials with pre-reduced metal colloids.1Both of them have been successfully used for making Pt/C catalyst.In making a supported metal catalyst, there has been reported a method based on a sonochemical process, not chemical reduction. Cu/polyaniline catalyst was synthesized by irradiating ultrasound to the organic solution composed of Cu precursor and aniline(solute)2. Aniline was polymerized and Cu precursor was reduced with the ultrasound irradiation simultaneously. The Cu/carbonized polyaniline catalyst was also synthesized by pyrolyzing the Cu/polyaniline. This method has the possibility of being applicable in making a Pt/carbonized polyaniline catalyst for fuel cell application because a carbonized polyaniline could be used as a support as reported in a previous result3 and Pt precursor is able to be reduced with the ultrasound irradiation4. Thus the development of Pt/carbonized polyaniline catalyst and its application in PEMFC were studied in this research.We used H2PtCl6·6H2O as a Pt precursor and aniline as a solvent for making catalyst of Pt/polyaniline. The mixture of Pt precursor and aniline was irradiated by ultrasound, and the product was perfectly dried in vaccum oven. The dried product was heated to carbonize polyaniline.Fig. 1 shows the X-ray diffraction (XRD) pattern of synthesized Pt/carbonized polyaniline. The pattern is identical with critical peaks of Pt metal. This result confirms a successful reduction of Pt precursor. The size of Pt particle was measured as 12.37 nm by treating Pt(111) peak with using Scherrer equation. The SEM-EDS (scanning electron microscope – energy dispersive spectroscopy, not shown here) analysis directly shows well dispersed Pt on carbonized polyaniline. Fig. 2 is XPS (X-ray photoelectron spectroscopy) data of Pt/carbonized polyaniline catalyst. The presence of metallic Pt was also confirmed with XPS data. The electrochemical properties Pt/carbonized polyaniline were evaluated through CV(cyclic voltammetry) and ORR (oxygen reduction reaction) tests. Furthermore, the performance of single cell made with Pt/carbonized polyaniline was measured and compared to that obtained with a conventional Pt/C catalyst.In this presentation, all the results investigated in the research will be presented with in-depth discussion.

Polyaniline salts as polymer‐based solid acid catalyst for low molecular weight poly(lactic acid)

ABSTRACTPolymer‐based solid acid catalyst, polyaniline (PANI) salt, is used for the first time to synthesize polymer. In continuation of our work to synthesize organic chemicals using PANI‐based solid acid catalyst, in this work, polylactic acid is synthesized by the condensation polymerization of lactic acid using PANI salts. PANI salts are characterized by FTIR, FE‐SEM, and TGA analyses. Polymerization of lactic acid in xylene solvent at 140°C for 24 h with the use of very low amount of PANI catalysts gave polylactic acid (PLLA) in the order: PANI‐MSA (46%) > PANI‐TFA (33%) > PANI‐Bi(OTf)3 (27%) > PANI‐Cu(OTf)2 (20%) > PANI‐Yb(OTf)3 (15%). Molecular weights of PLLA synthesized using PANI‐MSA and PANI‐TFA are found to be 4385 and 4830, respectively. This methodology gives highly crystalline polymer with mushroom cap‐like morphology. Advantage of this methodology is the use of easily synthesizable, recyclable, easily handlable, cheaper, and eco‐friendly nature of the catalyst. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41147.

Fe/Co/C–N nanocatalysts for oxygen reduction reaction synthesized by directly pyrolyzing Fe/Co-doped polyaniline

Development of precious metal-free catalysts for oxygen reduction reaction (ORR) is of great significance for the practical application of fuel cells. In this article, we report the finding that the C–N composites containing Fe and/or Co (C–PANI, Fe/C–PANI, Co/C–PANI, and FeCo/C–PANI), produced by directly pyrolyzing the Fe- and/or Co-doped polyaniline (PANI) precursors, show efficient electroactivity for ORR both in acidic and in alkaline media. Among the prepared catalysts, Fe/C–PANI and Co/C–PANI present the most positive ORR onset potential that is 0.61 V (vs. SCE) in 0.5 mol L−1 H2SO4 solution or −0.1 V (vs. SCE) in 1 mol L−1 NaOH solution. In addition, the Fe/C–PANI catalyst shows the largest limiting-diffusion current density for ORR both in acidic and in alkaline media. A four-electron reaction of ORR on the Fe/C–PANI and Co/C–PANI catalysts is more dominant than a two-electron reaction. Fe/C–PANI catalyst also presents good electrocatalytic activity stability for ORR both in acidic and in alkaline media.

Conducting Polyaniline is an Efficient Catalyst for Synthesis of 3,4-dihydropyrimidin-2-(1H)-one Derivative Under Solvent-Free Conditions

A novel effective synthesis of 3,4-dihydropyrimidin-2(1H)-one (DHPM) derivatives, using conducting polyaniline (PANI) as a catalyst from aldehydes, β-ketoester and urea under solvent free conditions has been described. The effect of organic solvents on the human body and the environment is hazardous and its disposal is a major problem. Hence, solvent less organic reaction have attracted attention of chemists. Solvent free solid-state reaction carried out using the reactant alone reduces the pollution, and is more economical and environment friendly. PANI catalyst and solvent free condition reduces the side reactions that occur in other protonated acid media. The use of the sonochemical method is a green route for the synthesis of dihydropyrimidinones (DHPM). Compared with the traditional reaction, this method has the advantage of shorter reaction time with excellent yield, purity of DHPM and low loading of raw materials. Polyaniline is a mild, stable, recyclable, cheaper and highly efficient catalyst and used several times with excellent yield for the dihydropyrimidinone synthesis. Polyaniline (PANI) was characterized by UV-Visible, FTIR, XRD and SEM studies. DHPM were characterized by NMR, MS and IR spectroscopy. In the present paper, a green approach for the synthesis of dihydropyrimidinone assisted by polyaniline as a catalyst under solvent-free conditions is reported.

ChemInform Abstract: New Route to N‐Formylation of Primary Amines with Amino Acids as a Source of CO Using Polyaniline Catalyst.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

New Route to N-Formylation of Primary Amines with Amino Acids as a Source of CO Using Polyaniline Catalyst

The treatment of primary amines with amino acids as a CO source in the presence of polyaniline emeraldine salts bring about N-formylation to give the corresponding formamides. This route to N-formylation methodology of primary amine represents the first reported example of a CO-transfer via radical mechanism by highly nanoporous polyaniline emeraldine salts catalyst.

Efficient oxidation of hydroquinone and alcohols by tailor-made solid polyaniline catalyst

We described the efficient and convenient catalytic oxidation of hydroquinone and primary/secondary alcohol compounds into benzoquinone and aldehyde/ketone using various oxidation states of polyaniline. We analyzed the oxidation catalyzing capabilities of the pernigraniline base polymer by designing a tailor-made catalyst to be used as a powerful oxidant, and it was easily recovered and regenerated for recycling.

Green Approach for the Synthesis of Quinoxaline Derivatives in Water Medium Using Reusable Polyaniline-sulfate Salt Catalyst and Sodium Laurylsulfate

Quinoxaline derivatives have been prepared in excellent yields using very low amount of reusable polyaniline catalyst or polyaniline and sodium laurylsulfate from various 1,2-dicarbonyls and 1,2-diamines in aqueous medium. This methodology is being reported for the first time. The advantages of the polyaniline based sold acid catalyst are easy synthesis, stability, easy handling, convenient work up procedure and reusability of the catalyst.

Polyaniline salts and complexes: Efficient and reusable catalyst for the one‐pot synthesis of 5‐(methoxycarbonyl)‐6‐methyl‐4‐phenyl‐3,4‐dihydropyrimidin‐2(1h)‐one

AbstractPolyaniline salts were prepared by doping polyaniline base with different Bronsted acids (sulfuric, nitric, phosphoric, perchloric, hydrochloric acid) and organic acids (p‐toluene sulfonic acid, 5‐sulfosalicylic acid). Polyaniline complexes were also prepared using Lewis acids (aluminum chloride, ferric chloride). Polyaniline salts and polyaniline complexes were used as catalysts in Biginelli reaction for 5‐(methoxycarbonyl)‐6‐methyl‐4‐phenyl‐3,4‐dihydropyrimidin‐2(1H)‐one synthesis. Benzaldehyde and urea were reacted with methyl acetoacetate using polyaniline‐p‐toluene sulfonate salt as catalyst with different reaction time, temperature, and amount of catalyst. The use of polyaniline catalysts is feasible because of the easy preparation, easy handling, stability, easy recovery, simple work‐up procedure, reusability, excellent activity with less amount of catalyst, and eco‐friendly nature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1741–1745, 2006