Precipitation and Coprecipitation

Abstract

The sections in this article are Introduction General Principles Governing Precipitation from Solutions Physico‐Chemical Considerations Chemical Considerations Process Considerations Influencing the Properties of the Final Product Influence of Raw Materials Influence of Concentration and Composition Solvent Effects Influence of Temperature Influence of p H Influence of Aging Influence of Additives Prototypical Examples of Precipitated Catalysts and Supports Silica as Support Material Active Aluminas Ni /Al 2 O 3 Catalysts by Coprecipitation V / P / O Catalysts for Butane Oxidation to Maleic Anhydride Conclusions

Revealing the Formation of Copper Nanoparticles from a Homogeneous Solid Precursor by Electron Microscopy

“…The synthesis of nanoparticles with predefined structural characteristics has therefore become an important research theme. Synthesis procedures include the aggregation of atomic species to form colloidal nanoparticles in liquid phase and the transformation of solid precursors by gas phase treatments to form supported nanoparticles . In the latter case, precursors often consist of a metal salt impregnated on a solid support or of a coprecipitate of the metal oxide and support material.…”

Ultra-tiny Co(OH)2 particles supported on graphene oxide for highly efficient electrocatalytic water oxidation

“…19 The ultra-tiny cobalt-based nanoparticle/GO was obtained via reducing the precipitation temperature to 0 C and decreasing the cobalt ion concentration. A large number of small crystal nucleus will form at low temperature once the solution system reaches the precipitation threshold, 20 while low cobalt ion concentration can stop the further growth of crystal nucleus. Fig.…”

Co-Precipitation Synthesis of Y2w3o12 and Al2w3o12 Submicronic Powders and Their Application in Polymer Matrix Composites

“…During synthesis of the amorphous precursors the pH, temperature, type of reactant salts and initial concentration, co-precipitation method, type of precipitant agent, its concentration and dripping speed, as well as, aging time are paramount factors to control the agglomeration degree of precursors [37,38]. Depending on the co-precipitation method and precipitant agent, hydroxide or carbonate-based precursors can be formed.…”

“…Actually, Ostwaldripening is caused by the higher solubility of small particles due to their high surface curvature compared to larger ones. Accordingly, small particles dissolve and the material is reprecipitated onto large particles[37].The pH of the aqueous suspension of pAlW-AHC-6 was monitored during 1 h of aging and it increases up to 6.4, as shown in Figure 5.5. An aging time of 10 min was chosen to keep the pH of the precursor suspension almost constant and to avoid the tendency of further growth of the precursor particles even when the formation of a carbonate precursor would be constrained by a short aging time.…”