Emerging trends in research and development on earth abundant materials for ammonia degradation coupled with H2 generation.

Ammonia, as an essential and economical fuel, is a key intermediate for the production of innumerable nitrogen-based compounds. Such compounds have found vast applications in the agricultural world, biological world (amino acids, proteins, and DNA), and various other chemical transformations. However, unlike other compounds, the decomposition of ammonia is widely recognized as an important step towards a safe and sustainable environment. Ammonia has been popularly recommended as a viable candidate for chemical storage because of its high hydrogen content. Although ruthenium (Ru) is considered an excellent catalyst for ammonia oxidation; however, its high cost and low abundance demand the utilization of cheaper, robust, and earth abundant catalyst. The present review article underlines the various ammonia decomposition methods with emphasis on the use of non-noble metals, such as iron, nickel, cobalt, molybdenum, and several other carbides as well as nitride species. In this review, we have highlighted various advances in ammonia decomposition catalysts. The major challenges that persist in designing such catalysts and the future developments in the production of efficient materials for ammonia decomposition are also discussed.

In this dynamic area, ammonia degradation to hydrogen fuel provides a valuable contribution in the carbon neutral economy. Ammonia has been used extensively in several industries and is considered an ideal candidate for hydrogen generation and storage due to its high hydrogen content. Consequently, the ammonia decomposition to yield green hydrogen has become a hot topic in research. Although numerous studies on ammonia decomposition have been conducted over the last few decades, still very few review articles on the most recent advances in this field of catalysis have been published. Through this review, systematic information on the types of decomposition catalysts including both noble (Ru) and non-noble earth abundant metals such as iron, nickel, cobalt, molybdenum, their carbides and nitrides, catalytic routes, as well as the reactivity and mechanism can be comprehended. The literature on newly discovered catalysts, specifically from the last five years, is well documented and explained in this review article. Furthermore, the effect of catalyst supports, their reaction kinetics and mechanistic insights have also been discussed. The challenges and opportunities associated with the decomposition catalysts are comprehensively explicated in the end.

Ammonia decomposition reaction (ADR) is a viable method for hydrogen storage in the form of chemical bonds.Catalysts composed of noble, non-noble metals, amides, imides, carbides, nitrides, and their combinations have been widely explored towards the ADR.Challenges and opportunities in the ammonia oxidation are pointed out.

Assembly of a coordination polymer with sulphate-capped pentamolybdate units and copper: synthesis, structure, magnetic and catalytic studies.

A new coordination polymer based on the sulphate-capped pentamolybdate unit has been synthesized from the reaction of {Mo3S7Br6}2- with copper(II) bromide and pyridine, in DMF. The as-synthesized compound, formulated as [CuII(C5H5N)4]3[{MoVI5O15(SO4)2}{CuII(C5H5N)3(DMF)(H2O)}][MoVI5O15(SO4)2]·2DMF (1), crystallizes in the monoclinic space group of P21/c. This compound has a one-dimensional double-chain coordination polymeric structure, composed of the pentameric {MoVI5O15(SO4)2} and the {CuII(C5H5N)4} units, and has been characterized in the solid-state with single-crystal and powder X-ray diffraction, infrared and optical spectroscopy, as well as thermal and magnetic studies. Due to its unique arrangement, the compound is observed to be nanoporous in nature, occupied by a co-crystallized DMF molecule. Surface area measurements confirm the presence of nano-sized pores within the compound. Variable temperature P-XRD studies show the framework to be stable up to a temperature of at least 100 °C. Due to its rigid framework and the presence of nano-sized pores, the compound was extensively studied as a catalyst for oxidative desulphurization of model oil and commercial diesel. The compound not only shows excellent performance for the removal of recalcitrant sulphur components, such as dibenzothiophene (DBT) in fuel oil (∼100% removal), but is also observed to show excellent turn-over-numbers, regeneration, and reproducibility during the catalytic process.