The unexpected activity of Pd nanoparticles prepared using a non-ionic surfactant template.

Pd deposits on vitreous carbon substrates were prepared by electrodeposition from liquid crystal phases (both micellar and hexagonal phases) consisting of self-assembled non-ionic surfactant molecules. The morphology of the deposits varied significantly with the concentration of the surfactant but all are made up of aggregated nanoparticles circa 9 nm in diameter. The deposits from the micellar phase of the surfactant offer the largest electroactive area and specific activity for the hydrogen evolution, oxygen evolution and reduction reactions and formic acid and ethanol oxidations. Unexpectedly the deposits lead to an increase in catalytic activity far in excess of that expected from an enhancement in electroactive area.