TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The semi-permeable particle has a mode particle size of 1-100 mu m. The volume of the multiple discrete cavities is at least 10% and up to and including 60% of the total dry semi-permeable particle volume. The average discrete cavity size is 100 nm to 5 mu m. The semi-permeable particle has an aspect ratio of 0.4. The semi-permeable particle further comprises a surface stabilizing material on the external particle surface; colloidal or fumed silica on the external particle surface. The semi-permeable particle comprises nanoparticles of catalytically active metallic materials comprising palladium, platinum, or nickel in the multiple discrete cavities, the nanoparticles having an effective diameter of 2-100 nm. The nanoparticles of catalytically active metallic materials have an effective diameter of 2-50 nm. The semi-permeable particle comprises at least one nanoparticle of catalytically active metallic materials comprising elements selected from palladium, platinum, rhodium, ruthenium, nickel, cobalt, iron, copper, silver, gold, iridium, or osmium.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The water-insoluble semi-permeable polymer is selected from polyester, polyamide, polyurethane, styrenic polymer, mono-olefin polymer, vinyl ester polymer, acrylic polymer, vinyl ether polymer, vinyl ketone polymer, and aliphatic cellulose ester polymer. The semi-permeable particle comprising a cavity stabilizing hydrocolloid that is selected from carboxymethyl cellulose (CMC), gelatin or gelatin derivative, protein or protein derivative, hydrophilic synthetic polymer, water-soluble microgel, polystyrene sulfonate, poly(2-acrylamido-2-methylpropanesulfonate), and polyphosphate, where each semi-permeable particle further comprises an amphiphilic (low HLB)block copolymer that is disposed at the interface of the multiple discrete cavities and the continuous polymeric phase. EXAMPLE - No suitable example given.