The design of water‐stable photo and electrocatalysts of metal–organic frameworks (MOFs) for its promising catalytic applications at long‐term irradiations or persisted current loads is extremely necessary but still remains as challenging. A limited number of reports on Ti‐MOF‐based catalysts for water splitting are only available to explain and understand the correlation between the nature of materials and MOFs array. Herein, spherical Ti‐MOFs and corresponding partially annealed hollow core–shell Ti‐MOFs (Ti‐MOF/D) are designed and the correlation with their photo(electro)catalytic water splitting performance is evaluated. The switchable valence state of Ti for the Ti‐MOF as a function of molecular bonding is the possible reason behind the observed photocatalytic hydrogen generation and light‐harvesting ability of the system. Besides, the defect state, solid core–shell mesoporous structure, and active sites of Ti‐MOF help to trap the charge carriers and the reduction of the recombination process. This phenomenon is absent for hollow core–shells Ti‐MOF/D spheres due to the rigid TiO2 outer surface although there is a contradiction in surface area with Ti‐MOF. Considering the diversity of Ti‐MOF and Ti‐MOF/D, further novel research can be designed using this way to manipulate their properties as per the requirements.

In this study, new metal chelate monomers based on nickel(II) maleate and chelating N‐heterocycles (2,2′‐bipyridine and 1,10‐phenanthroline) were synthesized and characterized. A detailed analysis of the main stages and features of the kinetics of thermal transformations of metal chelate monomers was carried out. Core‐shell nanomaterials containing nanoparticles of nickel oxide and metallic nickel in a stabilizing nitrogen‐containing polymer matrix were obtained by thermolysis of these monomers. The composition, properties and structure of the nanomaterials were studied using IR spectroscopy, thermal analysis, X‐ray diffraction, atomic force microscopy, scanning electron microscopy, high‐resolution transmission electron microscopy, and energy dispersive X‐ray spectroscopy. The tribological characteristics of NiO nanoparticles as lubricant additives were studied using a pin‐on‐disc tribometer. The coefficient of friction (COF) is the lowest at the optimum concentration of nanoparticles and increasing the concentration above the optimum level leads to an increase in COF.

In this work, we study the influence of various molecular weights of polyvinylpyrrolidone (PVP) on synthesis substituted hydroxyapatite. Using the scanning electron microscopy we estimated the size and morphology of the particle. We studied the structural transformations of phosphates and the effect of polymer sizes on the structure and morphology. We revealed the thermodynamic stability of the structure of hydroxyapatite due to experimental results.

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