Nitric oxide (NO) is a highly reactive toxic gas that forms as an intermediate compound during the oxidation of ammonia and is used for the manufacture of hydroxylamine in the chemical industry. Moreover, NO is a signaling molecule in many physiological and pathological processes in mammals, as well as a biomarker indicating the course of inflammatory processes in the respiratory tract. For this reason, the detection of NO both in the gas phase and in the aqueous media is an important task. This review analyzes the state of research over the past ten years in the field of applications of phthalocyanines, porphyrins and their hybrid materials as active layers of chemical sensors for the detection of NO, with a primary focus on chemiresistive and electrochemical ones. The first part of the review is devoted to the study of phthalocyanines and porphyrins, as well as their hybrids for the NO detection in aqueous solutions and biological media. The second part presents an analysis of works describing the latest achievements in the field of studied materials as active layers of sensors for the determination of gaseous NO. It is expected that this review will further increase the interest of researchers who are engaged in the current level of evaluation and selection of modern materials for use in the chemical sensing of nitric oxide.
Thermo‐chemical dealumination of zeolite Y is accompanied by formation of different mesopore types. Closed mesopores in the nuclei and open pores at the crystal surface occur due to decomposition of its corresponding frameworks which are unstable in steam. Third type of lattice mesopores is formed inside the microporous bulk after removal of aluminum atoms if the remaining hydroxyl nests dehydroxylate. This process leads to a rearrangement of the zeolite framework. In contrast to the observed phenomenon, the defects are healed by migrating of ortho‐silicic acid (H4SiO4) from the surface to the hydroxyl nests under conditions of suitable steaming. Since mesopores in USY zeolites (ultra stable Y) reduce their catalytic activity and the sorption capacity, they could be minimized by a proper treatment.
The H 2 sorption properties of the aluminophosphate zeolites AlPO 5, AlPO 31, AlPO 11, AlPO 36, and AlPO 8 at 77 K have been investigated. A series of H 2 adsorption isotherms has been obtained for cylin drical micropore channels in the aluminophosphate zeolites. The absolute values of the amount adsorbed α(P) for the mesoporous aluminophosphate materials and the effective density of adsorbed H 2 in the micropore space β*(P, d) have been determined. It has been demonstrated experimentally that the sorbate density depends on the size of the micropore channel of the zeolite d. Hydrogen sorption isotherms have been calculated from experimental isotherms. A procedure allowing β*(P, d) to be estimated for intermediate d values is presented.
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