Effects of Pd nanocube size of Pd nanocube-graphene hybrid on hydrogen sensing properties

Palladium (Pd) nanocubes-loaded graphene were synthesized by a simple chemical method for hydrogen sensing. Pd nanocubes of 25, 40, 55, 70 and 85 nm sizes were synthesized in colloidal state by a chemical route in two-steps ( seed-mediated growth) and then, simply reduced into graphene flakes by hydrazine in a simple one-step process. The hydrogen-sensing and electrocatalyst properties of the new Pd nanocube-graphene hybrid were investigated in detail. The resistivity-type sensor that used the Pd cube-graphene hybrid had a detectable range from 10,000 to 10 ppm with good response and linearity at room temperature. Our experiment showed that the Pd cube-graphene hybrid with bigger Pd nanocubes not only showed better response to H-2 gas molecules but also maintained its excellent H-2 sensing properties even with increases in working temperature. The effects of Pd nanocube size on the H-2 sensing performance of the Pd cube-graphene hybrid was explained by both spillover mechanism and influence of Pd size on hybrid state of two materials. (C) 2014 Elsevier B.V. All rights reserved.