A versatile chemical method for the formation of macroporous transition metal alloys from cyanometalate coordination polymers

A facile two-step synthetic route to macroporous metal and metal alloy frameworks from hydrogel-forming coordination polymers known as cyanogels is described. The polymerization of a chlorometalate and cyanometalate in aqueous solution results in the formation of a cyanogel that will auto-reduce at elevated temperatures to form metal alloys under an inert atmosphere. Cyanogels are versatile precursors to macroporous metals due to the large number of metal alloy systems that can be produced. This synthetic route is advantageous due to the production of uncontaminated final products of refractory metals at low temperatures. Transient reactive liquid sintering is shown to be the physical process through which macroporous metal forms from the cyanogel precursor.