Core-Shell Nanoparticulate Compositions And Methods

A method, comprising:

• (a) reducing a Pt(II) salt in the presence of excess C(6-18)-alkylamine with a lithium alkylborohydride to form an alkylamine-coated Pt metal nanoparticle;
• (b) contacting the alkylamine-coated Pt metal nanoparticle with a linking compound having a formula:
• HS—R1—R2
• where R1 is 3 to 18 carbon atoms long and R2 is a carboxylic acid or alcohol group;
• to form a Pt metal nanoparticle coated with linking compound;
• and
• (c) contacting the Pt metal nanoparticle coated with linking compound with at least one metal alkoxide to form metal alkoxide superposed on a Pt metal nanoparticle core;
• and
• (d) optionally hydrolyzing the metal alkoxide superposed on the Pt metal nanoparticle core, optionally in the presence of C(6-18)-alkylcarboxylic acid, to form a Pt metal core encapsulated by metal alkoxide shell;
• and
• (e) after step (d), optionally calcining the Pt metal core encapsulated by metal oxide shell to form a Pt metal core encapsulated by metal oxide shell.

A method, comprising:

• (a) contacting a hydrophilic metal oxide support with an organosilane to form a hydrophobic metal oxide support;
• and
• (b) contacting the hydrophobic metal oxide support with a plurality of core-shell nanoparticles, each nanoparticle comprising a late-transition-metal core encapsulated by a shell comprising metal alkoxide;
• (a) and (b) being performed so to form a structure comprising plurality of core-shell nanoparticles displayed on a siloxane intermediate layer that is attached to a metal oxide support;
• and
• (c) optionally calcining the structure comprising the plurality of core-shell nanoparticles displayed on a siloxane intermediate layer to form a plurality of core-shell nanoparticles comprising late-transition-metal core encapsulated by metal oxide shell displayed on a silica layer that is attached to a metal oxide support.