MXenes are 2D nanomaterials that are considered the materials of the future generation due to their high electrical conductivity, good biocompatibility, and ease of functionalization. This research work reports the electrochemical sensing of Vitamin B6 using the Manganese dioxide-inorganic phosphate/MXene brush-coated Carbon fiber paper electrode (MnO2-Pi/MXene/CFP) electrode for the first time. The three-dimensional Ti3C2Tx MXene nanosheets consisting of highly ordered, vertically aligned nanosheets with electrochemically deposited MnO2-Pi are capable of yielding a synergistic effect in combination with high electrochemical performance and large surface area of MnO2-Pi. The reported electrochemical sensor exhibited a wide linear dynamic range (0.06–650 µM) and a low-level detection limit of 0.021 µM. An increase in the anodic peak current confirms the rapid transfer of electrons transfer arising between the Ti3C2Tx MXene and MnO2-Pi. The results attained substantiate that the fabricated sensor has enhanced selectivity, reproducibility, and stability toward the electrochemical determination of Vitamin B6 in real samples. 

In the quest for more sustainable chemical processes, we devised a technique using electro-organocatalysis to synthesize bis-β-diketone compounds via Knoevenagel condensation of benzaldehyde and dimedone. Our approach involves a modified electrode fabricated via anchoring L-proline onto a carbon fiber paper electrode supported by poly-3,4-diaminobenzoic acid (PDABA), which enhances efficiency in addition to the simple catalyst separation from the reaction mixture in heterogeneous catalysis. The electrochemical and surface topographical studies for the fabricated electrode were carried out, revealing high efficiency in comparison to the bare carbon fiber paper electrode. This electrochemical reaction operates under mild conditions utilizing lithium perchlorate and acetonitrile, yielding high amounts of the desired product. This study showcases a promising pathway for producing valuable organic compounds in an environmentally friendly manner, marking a significant stride forward in sustainable synthesis practices. 

Food additives are essential constituents of food products in the modern world. The necessity of food processing went up rapidly as to meet requirements including, imparting desirable properties like preservation, enhancement and regulation of color and taste. The methods of identification and analysis of such substances are crucial. With the advancement of technology, a variety of techniques are emerging for this purpose which have many advantages over the existing conventional ways. This review is on different kinds of additives used in the food industry and few prominent methods for their determination ranging from conventional chromatographic techniques to the recently evolved nano-sensor techniques. 

MXenes are 2D nanomaterials that are considered the materials of the future generation due to their high electrical conductivity, good biocompatibility, and ease of functionalization. This research work reports the electrochemical sensing of Vitamin B6 using the Manganese dioxide-inorganic phosphate/MXene brush-coated Carbon fiber paper electrode (MnO2-Pi/MXene/CFP) electrode for the first time. The three-dimensional Ti3C2Tx MXene nanosheets consisting of highly ordered, vertically aligned nanosheets with electrochemically deposited MnO2-Pi are capable of yielding a synergistic effect in combination with high electrochemical performance and large surface area of MnO2-Pi. The reported electrochemical sensor exhibited a wide linear dynamic range (0.06–650 µM) and a low-level detection limit of 0.021 µM. An increase in the anodic peak current confirms the rapid transfer of electrons transfer arising between the Ti3C2Tx MXene and MnO2-Pi. The results attained substantiate that the fabricated sensor has enhanced selectivity, reproducibility, and stability toward the electrochemical determination of Vitamin B6 in real samples. 

Conventional methods for hydrogenation of organic compounds generally use corrosive catalysts and reagents, along with extreme conditions like high temperatures and pressures. Quenching of corrosive materials does not deter its negative impact on the environment, nor is one safe when it comes to working with high temperature and pressure. Electrochemical hydrogenation (ECH) has proven to be safe and green since most of the efficient reactions are conducted at ambient pressure and temperature, minimizing, and sometimes even negating the use of toxic catalysts and corrosive reagents as compared to conventional methods. This review therefore provides different strategies used for ECH in the past, modification of different electrodes, half reactions taken up for efficient energy usage and catalysts used for different hydrogenation reactions. It presents the advances in electrochemical hydrogenation reactions of organic compounds, starting from simple aliphatic compounds to complex polyaromatics and heterocyclic aromatic compounds. 

MXenes are recently advanced two-dimensional layered nanomaterials that have various characteristic properties for developing electrochemical sensors for bioanalytical applications, such as hydrophilicity, good biocompatibility, electrical conductivity, heightened ion transportation, and ease of functionalization. MXenes are revealed to be having applications in various other fields including energy storage, and catalysis. The combination of a layered structure, biocompatibility, and high surface functionalities makes MXene a highly versatile material for electrochemical sensing applications. The effect of various synthesis and functionalization strategies on tuning the properties of MXenes toward improving sensing abilities has been comprehensively discussed. This review article also discusses the relevance of early diagnosis of various biomarkers of chronic diseases via MXene modified electrochemical sensor for gaining a better understanding of their early diagnosis, disease progression, and risk assessment. Modification with MXenes improves the electrocatalytic functionality of the electrodes thereby improving their applicability in health and biomedical fields. 

The unbridled release of harmful endocrine disruptors (EDs) into the environment is deteriorating human and animal health. A facile and efficacious biosensor was developed by immobilizing laccase over electropolymerized poly anthranilic acid on a carbon fiber paper (CFP) electrode, Lac/PAA/CFP for the detection of p-nonylphenol (PNP). PNP is a persistent phenolic endocrine disruptor and a harmful eco-toxic pollutant. Physico-chemical and electrochemical characterization of the fabricated electrode was carried out to study the modification of the Lac/PAA/CFP electrode. Cyclic voltammetric studies divulged that the prepared sensor has catalytic activity approximately twice greater than that of the bare CFP electrode. The influence of pH and scan rate was scrutinized for the modified electrode. Under optimized conditions differential pulse voltammetric studies were used for the quantification and the results revealed that the biosensor has a low limit of detection (LOD) and limit of quantification (LOQ) of 1.74 nM and 5 Nm, respectively with a broad linear dynamic range of 5–250 nM. In the presence of interferants, the developed biosensor exhibited good selectivity toward the electrochemical detection of PNP. Molecular docking studies carried out revealed the hydrogen bonding interaction of the Asn264 residue of laccase Trametes versicolor. Further, the fabricated biosensor was accessed for its practicality in real samples collected from tap water and lake water. 

Flavonoids are bioactive polyphenolic compounds, widespread in the plant kingdom. Flavonoids possess broad-spectrum pharmacological effects due to their antioxidant, anti-tumor, anti-neoplastic, anti-mutagenic, anti-microbial, anti-inflammatory, anti-allergic, immunomodulatory, and vasodilatory properties. Care must be taken, since excessive consumption of flavonoids may have adverse effects. Therefore, proper identification, quantification and quality evaluations of flavonoids in edible samples are necessary. Electroanalytical approaches have gained much interest for the analysis of redox behavior and quantification of different flavonoids. Compared to various conventional methods, electrochemical techniques for the analysis of flavonoids offer advantages of high sensitivity, selectivity, low cost, simplicity, biocompatibility, easy on-site evaluation, high accuracy, reproducibility, wide linearity of detection, and low detection limits. This review article focuses on the developments in electrochemical sensing of different flavonoids with emphasis on electrode modification strategies to boost the electrocatalytic activity and analytical efficiency. 

Sustainable and environmentally benign synthesis methods have captured researchers' minds in recent times and have contributed a lot towards the green synthesis of organic compounds. This work presents an efficient green method for synthesizing 2-formyl thiophene using a newly designed Pi-MnO2 deposited on poly-3-thienylacetic acid coated Toray carbon fiber paper (PThAA-Pi-MnO2-TCFP) electrode. Cyclic voltammetry (CV), chronoamperometry (CA) and bulk electrolysis (BE) techniques were employed for the optimization and synthesis of 2-formyl thiophene and the product obtained was characterized by proton nuclear magnetic resonance (1HNMR) spectroscopy. The efficacy of the developed electrode was examined by different electrochemical and physicochemical studies. It is an intriguing approach for the 4-acetamido-TEMPO (4-ACT) mediated, PThAA-Pi-MnO2-TCFP catalyzed electro-oxidation of thiophene-2-ylmethanol (TM). This method is handy and reasonably practical since the developed electrocatalyst is inexpensive, and the synthesis is environmentally benign. Hence it is a highly efficient method for synthesizing 2-formyl thiophene, a much sought-after starting material in pharmaceuticals, agrochemicals, and cosmetics. 

Pi-MnO2-rGO-CFP electrode was developed through a concurrent deposition of Pi-MnO2 and reduced graphene oxide (rGO) on carbon fiber paper (CFP). Cyclic voltammetry (CV) and electrochemical impedance studies (EIS) were applied for the electrochemical characterization of the electrode. The electro catalytic activity of the modified electrode was improved by the increased synergistic characteristics of the CFP and electrochemically deposited rGO-Pi-MnO2 composite. The performance of the modified electrode was remarkable due to its lowest charge transfer resistance (Rct), and highest surface area offering more active sites and quicker electron transport kinetics. X-ray diffraction spectroscopy (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical profilometry (OP) were employed to study the physicochemical properties. Furthermore, the modified electrode was availed to oxidize piperonyl alcohol mediated by 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl (4-acetamido TEMPO or 4-ACT). The product obtained was purified and characterized by 1HNMR. The turnover frequency of 4-ACT was studied at different concentrations of the reactant, and the reaction parameters were also optimized using statistical tool design of experiment. This methodology is demonstrated to be economical, environmentally benign, and highly efficient in obtaining piperonal as it is carried out under milder reaction conditions. 

The progress of MXenes, a 2D layered structural material since its discovery in 2011 recently arouses a great deal of attention due to their plethora of applications in a diverse range of fields. Their excellent properties in terms of surface chemistry, optical activity, electrical conductivity, presence of abundant active catalytic sites, tunable band gap structure, ease of surface functionalization, and good biocompatibility make them an ideal candidate. The authors aim to guide the readers through various aspects such as their unique properties, synthesis techniques, and the recent advancements associated with MXene quantum dots (QDs). Herein, this review serves as a one-stop point for prospective researchers to gain a better understanding of the application of MXene QDs in various fields including electrochemical detection, biomedical applications, and energy conversion and storage applications. 

A facile and sustainable electrochemical synthetic strategy for phenyl benzimidazoles has been developed using a ferrocene-based electrocatalyst anchored on Toray carbon paper (TCP) coated with conducting polymeric film. The developed electrode was used for the electrochemical dehydrogenative cyclization reaction of o-phenylene diamine and benzaldehyde using lithium perchlorate/acetonitrile as electrolyte. The surface characteristic properties of the developed electrode were characterized by FESEM, Optical profilometer and X-ray photoelectron spectroscopy. Electron transfer mechanism of the anchored ferrocene-based electrocatalyst was thoroughly studied. To determine the efficacy of the catalyst, the electron transfer coefficient (0.5) and apparent rate constant 41.4 s−1 were determined. The cyclic voltammetry studies reveal that the electrochemical oxidation peak for the synthesis of benzimidazole occurs at 0.48 V. The formation of the product was confirmed by Gas chromatography and Nuclear Magnetic Resonance spectroscopy. A comparison chart is presented for the green metrics and sustainability of the present strategy with other electrochemical approach. 

Conducting polymers (CPs) are organic polymers with metallic conductivity or semiconducting properties which have drawn considerable attention globally. They are versatile materials because of their excellent environmental stability, electrical conductivity, economic importance as well as optical and electronic properties. CPs are interesting because they can be functionalized in several ways and the chemical properties are fine-tuned by incorporating new functionalities, making them more suitable in biomedical and other applications. They act as appropriate mediums of biomolecules and can be employed to improve the speed, stability, and sensitivity of various biomedical devices. They can transit between conducting and semiconducting states and have the ability to change mechanical properties by regulated doping, chemical modifications, etc. In this paper, we review the potential biomedical uses of conducting polymers such as smart textiles, bioactuators, hydrogels, and the use of CPs in neural prosthetic devices. 

Impressive characteristics of carbon fiber paper (CFP) electrodes propound greater demand in electrochemical applications. CFP has a network structure composed of interwoven carbon fibers (CFs). The macroporous structure, chemical inertness, high conductivity, low cost, corrosion resistance, good electrical properties, mechanical strength, and self-standing capabilities have led to the large-scale acceptance of CFP. This review appraises the current progress of CFP based electrodes for electrocatalytic applications in the field of electrochemical sensors, electrochemical capacitors, batteries, electro Fenton oxidation, electrooxidation of alcohols, water splitting, hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) together with the different fabrication strategies on the CFP substrate in an organized manner. The different modifiers used for surface tuning of CFP addressed in this review are the conducting polymers, carbon-based nanomaterials, transition metal dichalcogenides/phosphides/carbides, and nanostructured metal oxides. 

A modified electrode based on laccase immobilized poly-thiophene-3-carboxylic acid supported on carbon fiber paper was developed for the electrocatalytic oxidation of D-ribofuranose to otherwise difficult-to-access D-ribonolactone, a precursor for C-nucleoside based drug like Remdesivir. The electrochemical oxidation of D-ribofuranose was achieved by the TEMPO-mediated electrochemical process. The experimental parameters were optimized and validated using Design of Experiment (DoE) statistical tool indicating the concentration of TEMPO and stirring as important parameters in bulk electrolysis. The mechanism for the electrochemical oxidation of D-ribofuronose followed single electron anodic oxidation of TEMPO mediated by laccase to the corresponding oxoammonium nitrosonium species which was vital for the mediated electrochemical oxidation. The mechanism for the electrochemical oxidation was established using cyclic voltammetry and computational studies. The plausible interactions of laccase enzyme with TEMPO mediator were studied using molecular docking experiments. This facile method was successfully applied for the oxidation of D-ribofuranose to D-ribonolactone. 

Carbon quantum dots have recently gained widespread attention due to their excellent physicochemical features. The rapid escalation in the dumping of hazardous chemicals into water, spurred demand for developing efficient and selective sensors for toxic chemicals. Herein, we have developed a novel fluorescence sensor for picric acid which is a major pollutant in industrial effluents. The new strategy exploits the development of a fluorescence sensor based on N-doped carbon quantum dots (N-CQDs) followed by boron functionalization. The N-CQDs were synthesized in a rapid single-step microwave technique by employing L-serine and citric acid. Subsequent boron functionalization of N-CQDs was carried out using boric acid for the synthesis of Boron-nitrogen carbon quantum dots (B/N-CQDs). The B/N-CQDs were found to exhibit high quantum yield (24%), good water solubility, outstanding photostability features, and bright green fluorescence under UV light. The morphology of B/N-CQDs is spherical, with scattered particle sizes ranging from 2 to 8 nanometers. Furthermore, B/N-CQDs were found to be an effective fluorescence probe for the selective and sensitive detection of picric acid, with a good linear range of 37 nM-30 µM and a detection limit of 1.8 nM. The Photoluminescence (PL) intensity of B/N-CQDs was selectively quenched by picric acid. The quenching mechanism was conclusively established using fluorescence lifetime decay studies. Moreover, the synthesized B/N-CQDs was successfully employed for the analysis of picric acid from industrial effluents and cell imaging with Hela cells to showcase the utility of the developed fluorescent probe. 

Nitriles unveil widespread applications in pharmaceuticals, agrochemicals, textiles, rubber, polymers, and constitute a significant intermediate in several organic transformations, necessitating the design of simple and environmentally benign pathways for their synthesis. Over the recent years, electro-organic reactions have found widespread attention in developing effective and selective organic synthesis. They possess several advantages: high atom economy, selectivity, minimal waste production, and shorter routes to multistep traditional organic reactions. The development of novel strategies for greener and sustainable electro-organic synthesis of nitriles is therefore commendable. This review focuses on analyzing various methods and strategies used in the electrochemical synthesis of nitriles using phase transfer catalyst, N-oxoammonium salts mediated electrocatalysis, iodine-mediated electrocatalysis, and anodic oxidations of aldoximes. In addition, the recent trends including the synthesis of nitriles via C−H cyanation, domino oxidation, bio electrocatalysis, and metal-ligand cooperative synthesis have been discussed. 

The rediscovery of the old-age material graphitic carbon nitride (g-C3N4), a 2D conducting polymer, has given rise to a tide of articles exploring its diverse applications. Recently, owing to its excellent physicochemical stability and tunable electronic structure, the material has proven to be an eminent candidate for improving the sensing quality of electrodes. Excellent properties of g-C3N4 such as exposed surface area, metal-free characteristics, and low-cost synthesis have attracted facile and economical designing of sensors for a variety of analyte molecules. Herein, the readers are introduced to the historical development of g-C3N4 and escorted to the present findings of its electrochemical sensing applications. Along with its sensing utilities, the review shares some exciting insights into the synthesis, structural, and surface chemistry modulations of g-C3N4. A great many approaches for overcoming the inherent limitations have also been critically discussed, starting with the precursor in use. This review article aims to provide a concise perspective and direction to future researchers for enabling them to fabricate smart and eco-friendly sensors using g-C3N4. 

Electro-organic reactions are now considered as one of the most efficient and environmentally benign methodologies to synthesize highly functionalized motifs like difunctionalized unsaturated compounds from readily available substrates. Excellent regioselectivity, functional group tolerance and broad range of substrates are the main advantages of electrochemical difunctionalization reactions. Alkenes and alkynes readily accept radical or ionic derivatives which makes it vital precursors for the electrochemical synthesis of industrially relevant and biologically active molecules through difunctionalization. This review aims to provide the readers an excellent coverage of the different electrochemical difunctionalization of alkenes and alkynes such as 1,2-homodifunctionalization, 1,2-heterodifunctionalization, rearrangement, ipso-migration, cyclization and dehydrogenative annulation reactions. 

The conventional methods for carrying out fluorination of organic compounds are typically conducted using a pre-modified starting material, usually expensive and toxic reagents. In this regard, electrochemical fluorination has been recognized as a sustainable and scalable strategy. Electrofluorination has proven to be an environmentally benign, highly effective, and versatile platform for the synthesis of selective organofluorine compounds under mild conditions. This review provides an overview on the use of anodic electrochemical methods for vicinal difluorination, iodofluorination, fluoroalkynylation, fluorodecarboxylation, fluoro desulfurization, radiofluorination, and synthesis of fluorinated heterocycles. Modern advances in the field of electrochemical fluorination, such as ionic liquids mediated electrochemical fluorination, triethylammonium halides, mixed non-aqueous solvents, alkali–metal fluoride, and split-bipolar electrodes in the field of electrochemical fluorination are also discussed. 

Lewis acid ZnCl2 promoted cyclization protocol to 4H-chromenes is accomplished, using readily available phenols and acetophenones as starting materials. Interestingly, the process is feasible under the solvent free environment. Synthesis of a variety of 4H-chromenes have been accomplished using this strategy. In addition, this concept is extended to the synthesis of ortho-benzylphenols by treating phenols either with styrenes or secondary benzylic alcohols. 

A fluoro-based Schiff base (E)-2-fluoro-N′-(1-(4-nitrophenyl)ethylidene)benzohydrazide (FNEB) has been synthesized from condensation of 2-fluorobenzohydrazide and 4′-nitroacetophenone catalyzed by glacial acetic acid with ethanol as the solvent. The dipole moment of FNEB in both the electronic states were found using different solvatochromic approaches such as Lippert-Mataga, Bakhshiev, Kawski-Chamma-Viallet, Reichardt and Bilot-Kawski. The experimental ground state dipole moment of FNEB was calculated using Guggenheim-Debye method and theoretical ground state dipole moment using Bilot-Kawski solvatochromic approach. The solvatochromic behavior of the Schiff base in different solvents was studied using absorption and emission spectra. Catalan and Kamlet-Abboud-Taft parameters were used from the multiple linear regression (MLR) analysis in order to study the solute-solvent interaction. The dipole moments were also calculated using Time Dependent-Density Functional Theory (TD-DFT). The chemical stability of FNEB was determined using computational and Cyclic Voltammetry by the use of obtained energy gap between the frontier orbitals. Using the frontier orbitals energy gap, global reactivity parameters were computed. Further, Light Harvesting efficiency was determined to comprehend the photovoltaic property of the Schiff base.