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• Recent advances in tetrazole-based catalysts are described. • Environmental and catalytic applications of tetrazole-based (nano)materials have been presented. • Stability and catalytic properties of tetrazole-based (nano)materials are highlighted. • Future challenges on tetrazole-based (nano)materials are discussed. Increasing interest in tetrazoles and tetrazole based materials in the recent century has been followed by enormous research efforts devoted for the synthesis of various kinds of materials based on these five membered heterocyclic compounds, which basically contain four nitrogen atoms. The structure of tetrazoles and their derivatives are crucial in preparing complexes since they can act as ligands to modify the reactivity and selectivity of the metal centers in the catalyst and prepare energetic materials. The wide field of tetrazole applications as efficient, air stable and inexpensive materials has drawn attention to the methods to synthesize various kinds of tetrazoles and their derivatives. This study primarily focuses on the fabrication methods of tetrazoles and preparation of tetrazole based compounds and their utilizations in environmental, catalytic, and energetic applications. The significant applications of tetrazole, as a catalyst, energetic material and efficient ligand in the organic catalysis or formation of various catalysts are described with an emphasis on its performance, reusability and stability and environmental concerns such as treatment of wastewater and water. Finally, a brief summary and an outlook on some of the scientific challenges and opportunities of these materials have also been discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Advances in oxidation reactions by polymer supported cobalt complexes/nanoparticles, are described. • Summary of synthetic methods for attaining polymer supported cobalt complexes/nanoparticles. • Catalytic oxidation of mercaptans, alcohols, alkenes etc , are presented. • Mechanistic details are provided for oxidation with polymer supported cobalt complexes/nanoparticles. • Future challenges on oxidation reactions using polymer supported cobalt complexes/nanoparticles are discussed. Polymers play an important role in the fabrication of heterogeneous (nano)catalysts applied for many chemical syntheses and conversions. The excellent properties of polymers, for instance, high thermal stability, large surface area, simplicity of modification and high mechanical strength make them ideal catalyst supports. To reduce the toxicity of metal nanoparticles (MNPs) or complexes, a new method has been developed in recent years for the fabrication of supported MNPs. Synthesis of MNPs or metallic complexes on polymer support has been applied as a prospective solution to avoid the accumulation of waste MNPs in the medium via a recovery process. The blending of nanoparticles with polymers forms nanocomposites with unique properties due to their specific shape, size, and nature. This review is an overview of the current developments in manufacturing, characterization, and applications of cobalt (Co) complexes/NPs decorated on the surface of various polymers for the catalytic oxidation of mercaptans, alcohols, alkenes, etc. using various oxidizing agents such as H 2 O 2 , O 2 , TBHP (tert -butyl hydroperoxide), etc. Eventually, we envision the current/future challenges and opportunities for these polymer-supported cobalt (nano)catalysts in the field of chemical transformations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recent advances in graphene-based (nano)materials have been described. • Reduction of hazardous nitro compounds by graphene-based (nano)materials have been reviewed. • Characterization of graphene-based (nano)materials have been highlighted. • Future challenges on the reduction of hazardous nitro compounds are discussed. The rapid progresses in the reduction of nitro compounds represent a potent and extensively utilized transformation, which allows the introduction of amino compounds. From the standpoint of organic chemistry, amines have many applications in the synthesis of drugs, biologically active molecules, pharmaceutical products, dyes, polymers, etc. For this aim and owing to the environmental concerns about toxic nitro contaminants such as 4-nitrophenol (4-NP), up to know, much research has been carried out on the reduction/degradation of nitroarenes for the fabrication of amines using different heterogeneous (nano)catalysts. This review provides the current developments in the area of production, classification and applications of graphene-based catalysts in the reduction of nitro compounds to amines. The application of graphene derivatives in the synthesis of various catalysts is advantageous compared to other catalysts and thus increases the rate of reduction of nitro compounds. The use of these catalysts offers several benefits such as straightforward work-up, high catalytic prowess and recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advances in oxidation reactions by lignin derived (nano)catalysts, are described. • Summary of synthetic methods for attaining lignin derived (nano)catalysts. • Catalytic oxidation of alcohols, phenols, etc, are presented. • Mechanistic details are provided for oxidation with lignin derived (nano)catalysts. • Future challenges on oxidation reactions using lignin derived (nano)catalysts are discussed. Recently, the attention to bio-based catalysts has been on rise. The present review explains the developments regarding preparation, characterization and utilization of lignin based (nano)catalysts in oxidation reactions. Herein, the application of lignin in the preparation of (nano)catalysts and their catalytic prowess in oxidative transformations will be overviewed. Lignin offers exceptional physicochemical characteristics and important potential applications. Lignin can be used as a precursor or template to prepare novel eco-friendly catalysts. This review paper proposes the rational design of active, economical, recyclable and efficient catalysts for different oxidation reactions including oxidation of alcohols, phenols, etc. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advances in hydrogenation by polymer-supported palladium complexes, are described. • Synthetic methods are highlighted for attaining polymer-supported palladium complexes. • Catalytic hydrogenation of carbonyl- and nitro-compounds, alkynes, and alkenes, are presented. • Mechanistic details are provided for hydrogenation with polymer-supported Pd catalysts. • Future challenges pertaining to hydrogenation reactions using Pd catalysts, are discussed. Hydrogenation reactions are useful pathways and comprise an integral operation to generate valuable organic compounds. Hydrogenation reactions not only provide an effective route for the preparation of organic compounds such as amines, alkenes, alkanes, alcohols, etc. but also a significant technique to degrade environmental pollutants; reactions are often catalyzed by palladium (Pd) complexes supported on the surface of the polymers, viz. organic or non-organic and are widely deployed owing to their high efficiency, recyclability and good selectivity. Herein, an overview is presented on current developments for the generation of different classes of polymer supported palladium complexes, their characterization and application in hydrogenation of assorted compounds comprising double bonds such as carbonyl- and nitro-compounds, alkynes, and alkenes. The literature from 1981 onwards is summarized pertaining to the hydrogenation reactions deploying polymer-supported Pd complexes catalysts under diverse conditions with special emphasis on the distinguished role of polymers as support in the structural and morphological features of the ensuing catalysts. [ABSTRACT FROM AUTHOR]