Acidic cesium salts of phosphotungstic acid: Morphology, water content and ionic conductivity

Cesium salt of tungstophosphoric acid/mesoporous (zirconia–silica) composite for highly efficient synthesis of 7-hydroxy-4-methyl coumarin and removal of methylene blue

“… 10 To overcome these issues, acid salts of PW containing cations like NH 4 + , Cs + , Rb + , and K + with surface areas of 150 m 2 g −1 (ref. 11 and 12 ) can be prepared by supporting them on suitable supports such as mesoporous molecular sieves MCM-41, 13 silica, 14 silica-alumina, 15 activated carbon, 16 zeolites, 17 metal–organic framework 18,19 and other methods to increase surface area and, as a result, catalytic activity and longevity. To some extent, combining silica and zirconia enhances the surface area of zirconia while also improving its acidity and stability.…”

Synthesis and Properties of Rubidium Salts of Phosphotungstic Acid

“…Rubidium salts of phosphotungstic acid (PTA) are one of the classes of heteropoly compounds that can be used in various fields, including the development of effective materials for electrochemical devices, such as fuel cells, gas sensors, and redox flow batteries [1][2][3][4][5][6][7][8][9][10]. Water-insoluble salts of PTA are widely used in organic catalysis [11][12][13], electrocatalysis [14], doping of polymer membranes [1,2,15,16], and various other fields due to an excellent combination of properties: high acidity, specific surface area (SSA), porosity, thermal stability, proton conductivity, and low solubility in water [17][18][19][20][21][22][23][24]. Water-insoluble salts of PTA (containing cations such as cesium, rubidium, ammonium, or silver) have improved properties compared with the initial acid.…”

“…Insoluble salts of PTA self-assemble into large particles (with an average size of 100-2000 nm) during the synthesis process. These agglomerates are composed of small crystallites 10-50 nm in size [21,[23][24][25][26][27][28][29][30]. This structure determines the developed surface and high porosity.…”

“…Thus, by varying the synthesis parameters, it is possible to change the sizes of crystallites and particles/agglomerates, SSA, porosity, composition, ionic conductivity, etc. [18,21,23,24,41,42]. To obtain the most active catalysts, different synthesis parameters are varied: the type of initial reagents, their concentration and ratio, precipitate washing modes, synthesis temperature, and subsequent annealing temperature.…”

“…To obtain the most active catalysts, different synthesis parameters are varied: the type of initial reagents, their concentration and ratio, precipitate washing modes, synthesis temperature, and subsequent annealing temperature. From this point of view, cesium salts of PTA have been most widely studied [19,23,24,32]. In addition, there are a number of publications on ammonium [19,21,43,44], potassium [32,45,46], and silver [30,47,48] salts.…”