For past several years, precious alloys have been gradually replaced by non-precious ones in the dental casting field because of the rising price of dental alloys. In Japan during the past ten years, nickel-chromium alloys have been used extensively for crown or bridge and porcelain-fused-to-metal restorations instead of gold or silver alloys. This tendency seems to be the same all over the wor...

Transition metal carbides and nitrides have received a large amount of attention in chemistry and materials science due to their interesting properties and potential to substitute precious metal catalysts. Earthabundant early transition metal carbides and nitrides were the primary focus of many efforts, while late transition metal alternatives are less explored. This brief review discusses rece...

1. Materials synthesis and characterization Catalyst synthesis: Commercially available TiO 2 , with the particle size ranging from 50 to 150 nm and in the B.E.T. surface area from 50 to 100 m 2 /g, was first treated in 0.5 M HCl solution for 24 hours to remove impurities. In a typical approach to the synthesis of the PANI-Fe-TiO 2 catalyst, 2.0 mL aniline was first dispersed in 0.5 M HCl soluti...

Polarization caused by the oxygen reduction reaction (ORR) on cathodes still contributes significantly to the energy efficiency loss of metal–air batteries and fuel cells. Thus, ways of increasing the ORR kinetics while maintaining fast mass transfer is a grand challenge in the development of a new generation of metal–air batteries and fuel cells. Catalysts based on platinum and other precious ...