Transport properties of spiral carbon nanofiber mats containing Pd metal clusters using Pd2(dba)3 as catalyst

TL;DR

This study investigates the microstructure and electrical transport properties of spiral carbon nanofiber mats containing Pd clusters, grown via Pd2(dba)3 catalysis, revealing unique conduction behaviors and multiple charge carriers.

Contribution

It presents a novel synthesis method for spiral carbon nanofibers with Pd clusters and analyzes their transport properties within a heterogeneous model framework.

Findings

Conductivity follows an exponential temperature dependence.

Thermopower exhibits linear behavior down to 40 K.

Sign change in thermopower indicates multiple charge carriers.

Abstract

We have grown spiral carbon nanofibers containing Pd metal clusters using the Pd2(dba)3 catalyzed decomposition of gaseous acetylene on molecular sieves (AlPO4-5) support. The microstructure and composition of the spiral carbon nanofibers were examined by the powder x-ray diffractometer and transmission electron microscope. The conductivity of the mat in the temperature range from 14 to 250 K could be described by the form of exp[-(T-1/4)]. The thermopower shows a remarkably linear behavior down to 40 K, reminiscent of some conducting polymers. The sign change of the thermopower suggests there exists more than one type of charge carrier, which could be ascribed to the different types of nanotube with various sizes of radius. The transport behavior of spiral carbon nanofibers containing Pd metal clusters will be discussed in the framework of the heterogeneous model.