Metal-organic framework based electrode materials for lithium-ion batteries: a review.

Metal-organic frameworks (MOFs) with efficient surface and structural properties have risen as a distinctive class of porous materials through the last few decades, which has enabled MOFs to gain attention in a wide range of applications like drug delivery, gas separation and storage, catalysis and sensors. Likewise, they have also emerged as efficient active materials in energy storage devices owing to their remarkable conducting properties. Metal-organic frameworks (MOFs) have garnered great interest in high-energy-density rechargeable batteries and super-capacitors. Herein the study presents their expanding diversity, structures and chemical compositions which can be tuned at the molecular level. It also aims to evaluate their inherently porous framework and how it facilitates electronic and ionic transportation through the charging and discharging cycles of lithium-ion batteries. In this review we have summarized the various synthesis paths to achieve a particular metal-organic framework. This study focuses mainly on the implementation of metal-organic frameworks as efficient anode and cathode materials for lithium-ion batteries (LIBs) with an evaluation of their influence on cyclic stability and discharge capacity. For this purpose, a brief assessment is made of recent developments in metal-organic frameworks as anode or cathode materials for lithium-ion batteries which would provide enlightenment in optimizing the reaction conditions for designing a MOF structure for the battery community and electrochemical energy storage applications.

Electrochemical sensing platform for the simultaneous femtomolar detection of amlodipine and atorvastatin drugs.

The development of a proficient and ultra-high sensitive functionalized electrode for accurate analysis of drugs is a long-standing challenge. Herein, we report an electrochemical nanocomposite scaffold, comprising of silver nanoparticles integrated with functionalized carbon nanotubes (COOH-CNTs/Ag/NH2-CNTs) for the simultaneous quantification of two widely used amlodipine (AM) and atorvastatin (AT) drugs. The sandwiched nanocomposite materials were thoroughly characterized morphologically and structurally. The nanocomposite COOH-CNTs/Ag/NH2-CNTs immobilized over glassy carbon electrode catalyzed electron transfer reactions at the electrode-electrolyte interface and facilitated detection of targeted drugs, as revealed by the significant decrease in oxidation potentials at 879 mV and 1040 mV and improved current signals. Electrochemical characterization and testing show that the functionalized porous architecture with a large effective surface area is a promising scaffold for the sensing of a binary mixture of AM and AT with limits of detection in the femtomolar range (77.6 fM, and 83.2 fM, respectively). Besides, the specificity, stability, and reliability of the electrochemical sensing platform in simple and complex biological and pharmaceutical samples with high percentage recoveries highlight its scope for practical applications. Computational studies supported the experimental outcomes and offered insights about the role of modifier in facilitating electron transfer between transducer and analytes.

Phenolic water toxins: redox mechanism and method of their detection in water and wastewater.

Phenolic pollutants are highly toxic and persistent in the environment. Their efficient detection is a pressing social demand. In this regard we introduce a novel ultrasensitive electroanalytical platform for the individual and synchronized detection of three phenolic isomers commonly known as hydroquinone (HQ), resorcinol (RC), and catechol (CC). The sensing device consists of a glassy carbon electrode (GCE) modified with functionalized carbon nanotubes (fCNTs) and gold-silver (Au-Ag NPs) bimetallic nanoparticles. The sandwiched scaffold represented as fCNTs/Au-Ag NPs/fCNTs/GCE efficiently senses HQ, RC, and CC with detection limits of 28.6 fM, 36.5 fM and 42.8 fM respectively. The designed sensor is more promising than reported sensors for phenolic toxins in the context of high sensitivity, selectivity, and rapid responsiveness. The designed sensor also shows the qualities of stability, reproducibility, reliability, and selective recognition capacity for target analytes in multiple real water samples. Moreover, computational calculations explain the function of the electrode modifier in facilitating charge transfer between the transducer and analytes.

Photocatalytic Dehydrogenation of Formic Acid on CdS Nanorods through Ni and Co Redox Mediation under Mild Conditions.

Selective release of hydrogen from formic acid (FA) is deemed feasible to solve issues associated with the production and storage of hydrogen. Here, we present a new efficient photocatalytic system consisting of CdS nanorods (NRs), Ni, and Co to liberate hydrogen from FA. The optimized noble-metal-free catalytic system employs Ni/Co as a redox mediator to relay electrons and holes from CdS NRs to the Ni and Co, respectively, which also deters the oxidation of CdS NRs. As a result, a high hydrogen production activity of 32.6 mmol h-1 g-1 from the decomposition of FA was noted. Furthermore, the photocatalytic system exhibits sustained H2 production rate for 12 h with sequential turnover numbers surpassing 4×103 , 3×103 , and 2×103 for Co-Ni/CdS NRs, Ni/CdS NRs, and CoCl2 /CdS NRs, respectively.

Metal- and Carbon-Based Materials as Heterogeneous Electrocatalysts for CO2 Reduction.

Climate change caused by continuous rising level of CO2 and the depletion of fossil fuels reserves has made it highly desirable to electrochemically convert CO2 into fuels and commodity chemicals. Implementing this approach will close the carbon cycle by recycling CO2 providing a sustainable way to store energy in the chemical bonds of portable molecular fuels. In order to make the process commercially viable, the challenge of slow kinetics of CO2 electroreduction and low energy efficiency of the process need to be addressed. To this end, this review summarizes the progress made in the past few years in the development of heterogeneous electrocatalysts with a focus on nanostructured material for CO2 reduction to CO, HCOOH/HCOO-, CH2O, CH4, H2C2O4/HC2O-4, C2H4, CH3OH, CH3CH2OH, etc. The electrocatalysts presented here are classified into metals, metal alloys, metal oxides, metal chalcogenides and carbon based materials on the basis of their elemental composition, whose performance is discussed in light of catalyst activity, product selectivity, Faradaic efficiency (FE), catalytic durability and in selected cases mechanism of CO2 electroreduction. The effect of particle size, morphology and solution-electrolyte type and composition on the catalyst property/activity is also discussed and finally some strategies are proposed for the development of CO2 electroreduction catalysts. The aim of this article is to review the recent advances in the field of CO2 electroreduction in order to further facilitate research and development in this area.