Advanced Functionalized Nanoclusters (Cu, Ag, and Au) as Effective Catalyst for Organic Transformation Reactions.

A considerable amount of research has been carried out in recent years on synthesizing metal nanoclusters (NCs), which have wide applications in the field of optical materials with non-linear properties, bio-sensing, and catalysis. Aside from being structurally accurate, the atomically precise NCs possess well-defined compositions due to significant tailoring, both at the surface and the core, for certain functionalities. To illustrate the importance of atomically precise metal NCs for catalytic processes, this review emphasizes 1) the recent work on Cu, Ag, and Au NCs with their synthesis, 2) the parameters affecting the activity and selectivity of NCs catalysis, and 3) the discussion on the catalytic potential of these metal NCs. Additionally, metal NCs will facilitate the design of extremely active and selective catalysts for significant reactions by elucidating catalytic mechanisms at the atomic and molecular levels. Future advancements in the science of catalysis are expected to come from the potential to design NCs catalysts at the atomic level.

Enzyme immobilized nanomaterials as electrochemical biosensors for detection of biomolecules.

Biosensors have emerged as a potential tool for selective and sensitive detection. Biomolecules like enzymes, deoxyribonucleic acid (DNA), and antibodies are used as recognition sites in biosensors due to their high selectivity, sensitivity, and signal-to-noise ratio. Nowadays, biosensors are used to detect many vital biomolecules such as glucose, urea, and cholesterol. Exploiting enzymes for the selective detection of target molecules are very good but may not be easily accomplished as enzymes often need to be immobilized onto support materials, which requests either modifying the surface or using appropriate linkers to synthesize biosensors. Currently, many biosensors' signal strength and stability still are low, which encourages the fabrication of functionalized nanomaterials/nanoparticles to enhance electrochemical performance. The review covers current progress in modifying enzyme immobilized biosensors to detect biologically essential molecules (glucose, urea, cholesterol). A discussion of the different types of enzyme immobilization is also provided. This review may be helpful for researchers to build rational and novel biosensors for efficient enzyme immobilization and sensing applications.

Simultaneous detection of aqueous aluminum(III) and chromium(III) using Persea americana reduced and capped silver nanoparticles.

There is a significant interest to develop sensing devices that detect water toxins, especially heavy metal ions. Although there have already been numerical reports on detecting toxic heavy metal ions, the use of adaptable devices could enable a broader range of sensing applications. Here, we used fresh peel extract (PeA) and dried peel extract (DPeA) of Persea americana (Avocado) as a reducing and capping agent to synthesize and stabilize AgNPs. The dimensions of NPs were controlled by tuning pH, temperature, and volume of the reducing agent. The sensitivity and selectivity of the AgNPs toward various metal ions viz. Ni(II), Cd(II), Al(III), Hg(II), Cr(III), Ba(II), Pb(II), Zn(II), Co(II), Mn(II), Cu(II), Ca(II), Mg(II), and K(I) were studied. The detection probe was found to be selective and sensitive toward Al(III) and Cr(III) ions with the detection limit of 0.04 ppm and 0.05 ppm, respectively. High-resolution transmission electron microscope (HRTEM), ultraviolet-visible (UV-Vis) spectroscopy, and dynamic light scattering (DLS) analysis results confirm an agglomeration-based mechanism for sensing both metal ions. This method can be exploited for the colorimetric detection of toxic heavy metals in real water samples.

This is the first study to report the use of avocado peel extract to synthesize AgNPs in sensing aqueous Al(III) and Cr(III) at trace level concentration.

Recent progress in g-C3N4, TiO2 and ZnO based photocatalysts for dye degradation: Strategies to improve photocatalytic activity.

Water contamination by dyes is a matter of concern for human health and the environment. Various methods (membrane separation, coagulation and adsorption) have been explored to remove/degrade dyes. However, now the exploitation of semiconductor assisted materials using renewable solar energy has emerged as a potential candidate to resolve the issue. Although, single component photocatalysts (ZnO, TiO2, ZrO2) were experimented, due to their low efficiency and stability due to the high recombination rate electron-hole pair and inefficient visible light absorption, composites of semiconductor materials are being used. Semiconductor heterojunction systems are developed by coupling two or more semiconductor components. The synergistic effect of their properties, such as adsorption and improved charge carrier migration, is observed to increase overall stability. This review covers recent progress in advanced nanocomposite materials based on g-C3N4, TiO2 and ZnO used as photocatalysts with details of enhancing the photocatalytic properties by heterojunctions, crystallinity and doping. The conclusion at the end displays a summary, research gaps and future outlook. A holistic analysis of recent progress to demonstrate the efficient heterojunctions for photodegradation with optimal conditions, this review will be helpful for the development of efficient heterostructured systems for photodegradation. This review covers references from the year 2017-2020.

Recent advances in visible-light-driven carbon dioxide reduction by metal-organic frameworks.

Metal-organic frameworks (MOFs) have emerged as promising materials and have attracted researchers due to their unique chemical and physical properties-design flexibility, tuneable pore channels, a high surface-to-volume ratio that allow their distinct application in diverse research fields-gas storage, gas separation, catalysis, adsorption, drug delivery, ion exchange, sensing, etc. The rapidly growing CO2 in the atmosphere is a global concern due to the excessive use of fossil fuels in the current era. CO2 is the prime cause of global warming and should be ameliorated either through adsorption or conversion into value-added products to protect the environment and mankind. Nowadays, MOFs are exploited as a photocatalyst for applications of CO2 reduction. Since the use of semiconductors limits the use of visible light for photocatalytic reduction of CO2, MOFs are promising options. The current review describes recent development in the application of MOFs as host, composites, and their derivatives in photocatalytic reduction of CO2 to CO and different organic chemicals (HCOOH, CH3OH, CH4). Efficient charge separation and visible light absorption by incorporation of active sites for efficient photocatalysis have been discussed. The selection of material for high CO2 uptake and potential strategies for the rational design and development of high-performance catalysts are outlined. Major challenges and future perspectives have also been discussed at the last of the review.