A method for preparing a colloidal dispersion of precious metal nanoparticles free of organic adsorbates that have a molar weight above 100 g/mol, the colloidal dispersion of the precious metal nanoparticles obtained by the method according to the invention, solid and re-dispersed precious metal nanoparticles and products comprising colloidally dispersed or solid precious metal nanoparticles.

Methods for producing nanostructures from copper-based catalysts on porous substrates, particularly silicon nanowires on carbon-based substrates for use as battery active materials, are provided. Related compositions are also described. In addition, novel methods for production of copper-based catalyst particles are provided. Methods for producing nanostructures from catalyst particles that comprise a gold shell and a core that does not include gold are also provided.

A composition of matter useful for catalyzing an alkene epoxidation reaction using molecular oxygen (O.sub.2) as an oxidant. including a plurality of structures comprising nanostructures or microstructures each comprising a coinage metal: and a plurality of single oxophilic metal atoms. The oxophilic metal is characterized by an oxide formation enthalpy being more exothermic than that of the coinage metal. In one or more examples. the oxophilic atom comprises nickel and the coinage metal comprises silver, and a concentration of the nickel increases selectivity to greater than 85% for the epoxidation reaction CH.sub.2CH.sub.2+O.sub.2.fwdarw.(CH.sub.2).sub.2O over combustion of ethylene forming carbon dioxide. and for an ethylene conversion of greater than 5%.

A hybrid catalytic nanoreactor having selectivity and stability in presence of air is provided for reduction reactions including semi-hydrogenations comprising of light harvesting dendritic plasmonic colloidosomes (DPC) of gold preferably as black gold and co-acting synergistically active catalytic sites of Pt-doped Ru bimetallic nanoparticles for desired significantly special selectivity and air-stability as a plasmonic reduction catalyst favoring plasmon-mediated simultaneous reduction and oxidation of metal active sites for facilitating reduction reactions including semi-hydrogenation activity. Said black gold/RuPt catalyst showcases good efficiency in acetylene semi-hydrogenation, attaining over 90% selectivity with ethene production rate of 320 mmol g.sup.1 h.sup.1 with its stability evident from 100 h of operation with continuous air flow, attributed to the synergy of co-existing metal oxide and metal phases. The catalyst's stability is further enhanced by plasmon-mediated concurrent reduction and oxidation of the active sites, facilitating its end use and applications in chemical industries, petrochemical industries, and applications catalysis.

A method for preparing a cracking catalyst includes combining a zeolite, an alumina binder, and phosphoric acid to form an extrusion mixture. The phosphoric acid acts as a peptizing agent. The extrusion mixture comprises from 0.000271 weight percent to 0.1 weight percent phosphoric acid based on the total weight of the extrusion mixture. The method further includes extruding the extrusion mixture to produce an extrudate. During the extruding, the phosphoric acid peptizes the alumina binder in the extrudate. The method further includes drying and calcining the extrudate to produce the cracking catalyst.

A hollow spherical catalyst for a fixed bed with internal fluidization of particles and a method for preparing the same. The preparation method includes: fully mixing precious metal nanopowder with an organic oil phase to form an internal oil phase; preparing a gel ball of an oil-in-water structure by taking an aluminum oxide molding solution as an outer aqueous phase using an independently researched and developed coaxial dual-dropper forming apparatus; and then preparing a hollow aluminum oxide catalyst containing precious metal powder from the gel ball through processes of aging, calcination, and reduction. The resulting catalyst is expressed as X@Al.sub.2O.sub.3, where the precious metal nanopowder X is wrapped inside hollow Al.sub.2O.sub.3, and the catalyst has an outer diameter of 1.5-5.0 mm, a shell pore diameter (aluminum oxide) of 10-50 nm, and the precious metal nanopowder sized 200-500 nm.