One of the strategic goals in crystal engineering is to synthesize the crystals with predictable structures and valuable properties. Metal Organic Frameworks (MOFs), a new class of crystalline porous materials, is a recent upsurge of interest in materials research. The challenges in the area encompass the deliberate control of structure, and therefore the properties and function, as many synthetic factors play a subtle role in the crystallization of MOFs. Among many influencing factors, nature of solvents, pH, molar ratio of reactants and temperature are four crucial parameters that determine the overall architectures of MOFs. This review presents the effect of these major parameters on the synthesis of several MOFs to clearly understand their influence on the nature of binding and formation of different MOF structures

Photocatalysis is a facile and sustainable approach for energy conversion and environmental remediation by generating solar fuels from water splitting. Due to their two-dimensional (2D) layered structure and excellent physicochemical properties, molybdenum disulfide (MoS₂) has been effectively utilized in photocatalytic H₂ evolution reaction (HER) and CO₂ reduction. The photocatalytic efficiency of MoS₂ greatly depends on the active edge sites present in their layered structure. Modifications like reducing the layer numbers, creating defective structures, and adopting different morphologies produce more unsaturated S atoms as active edge sites. Hence, MoS₂ acts as a cocatalyst in nanocomposites/heterojunctions to facilitate the photogenerated electron transfer. This review highlights the role of MoS₂ as a cocatalyst for nanocomposites in H₂ evolution reaction and CO₂ reduction. The H₂ evolution activity has been described comprehensively as binary (with metal oxide, carbonaceous materials, metal sulfides, and metal-organic frameworks) and ternary composites of MoS₂. Photocatalytic CO₂ reduction is a more complex and challenging process that demands an efficient light-responsive semiconductor catalyst to tackle the thermodynamic and kinetic factors. Photocatalytic reduction of CO₂ using MoS₂ is an emerging topic and would be a cost-effective substitute for noble catalysts. Herein, we also exclusively envisioned the possibility of layered MoS₂ and its composites in this area. This review is expected to furnish an understanding of the diverse roles of MoS₂ in solar fuel generation, thus endorsing an interest in utilizing this unique layered structure to create nanostructures for future energy applications.

Ammonium nitrate (AN) has received attraction globally not only as a nitrogenous fertilizer but also as an oxidizer in gas generators and propellants. Nowadays, great attention is being focused on the development of composite solid propellants with green oxidizers in realizing eco–friendly combustion products. The ammonium perchlorate (AP), which is the work horse oxidizer in composite propellant, needs replacement due to its environmental and human health issues. In this context, AN is regarded as an alternative to AP because of its easy availability and environmentally friendly chlorine free combustion products. However, AN has its own inherent drawbacks such as hygroscopicity, room temperature phase transition, and low burning rate. Recently, several studies have been focused on its phase stabilization and burning rate modification so as to develop solid propellants with improved properties. The knowledge of thermal characteristics of AN is a crucial factor for its applications in propellants and gas generators. This article details the different aspects of polymorphism, phase stabilization, thermal decomposition, hygroscopicity, specific impulse, and burn rate modification of AN and also addresses ways to overcome the inherent weakness of AN as a propellant oxidizer in formulating an effective propellant composition.

A new class of functional materials, carbon nitrides, has recently attracted the attention of researchers.