Most ruthenium is used in the electronics industry for chip resistors (Manufacturing Method Of Ruthenium Oxide Powder (2017)), and electrical contacts.
Ruthenium oxide is used in the chemical industry to coat the anodes of electrochemical cells for chlorine production (Carried Ruthenium Oxide Catalyst Method For Manufacturing The Same And Method For Manufacturing Chlorine (2002)).
Ruthenium is also used in catalysts for ammonia (Ruthenium Catalysts And Their Use In Ammonia Production (1984)) and acetic acid production (Acetic acid production methods incorporating tin or ruthenium catalyst stabilizers (2007)).
Ruthenium compounds can be used in solar cells, which turn light energy into electrical energy (Ruthenium Complex For Dye-Sensitized Solar Cell (2014)).
Ruthenium is one of the most effective hardeners for platinum and palladium, and is alloyed with these metals and others to make electrical contacts (New gold-palladium-ruthenium alloy for contact coatings of miniature switches especially telecommunications relays (1999)), and electrodes for severe wear resistance (Alloy with Ruthenium and spark plug with this alloy (2001)).
It is used in some jewellery as an alloy with platinum and other metals (Composition for jewelry (2000)).
References:
All patent information has been obtained from Espacenet (European Patent Office).