Fabrication and catalytic properties of Pd and Ce decorated carbon nanotube-TiO2 composite catalysts for low-temperature CO oxidation

In this paper, a series of Pd-Ce/acid-treated carbon nanotube (TCNT)-TiO2 composite catalysts were designed and fabricated carefully for low temperature CO oxidation. After covering of TiO2 on the surface of CNT, the catalytic activity enhanced obviously because of the synergetic effect of CNT and TiO2. The composite material CNT-TiO2 was more suitable for the catalytic support than only TCNT or TiO2. The experimental conditions, such as the ratio of CNT/TiO2, the prepared method of Pd nanoparticles, the effect of the Ce element, etc., were investigated in detail. The final result showed that Pd-Ce/TCNT-TiO2 catalyst prepared by NH3 coordination impregnation method when TCNT:TiO2 = 12:88–24:76 had superior activity on low temperature CO oxidation. The high dispersion of Pd nanoparticles and enriched surface Pd species on the Pd-Ce/CNT-TiO2 catalyst prepared by NH3 coordination impregnation method was the two main reasons of obtaining higher catalytic performance. By adjusting the research conditions, the CO molecules could be complete oxidized at about 35 °C, which was lower than many catalysts reported in the existed literature.