First-principles simulations of dissociated and molecular H2 adsorption on Pd4-cluster-functionalized carbon nanotubes

First-principles simulations were performed to study the effect of hydrogen dissociation on the transport properties of Pd(4)-cluster-functionalized carbon nanotubes. The band structure analysis indicates that within the diffusive region, hydrogen dissociation enhances the conductivity of Pd(4)-cluster-functionalized CNTs, especially at high-coverage. In the high-coverage case, the Pd-cluster-functionalized CNT changes from a semiconductor to a conductor because of a major structural change. At medium and low coverages, the increase of conductivity is due to the reduced localization of electrons. The conductance change suggests that the system may serve as a hydrogen sensor.