Novel multi‐wall carbon nanotubes (MWCNTs) supported Pd–Au catalyst for electrooxidation of formic acid was prepared and compared with a similarly prepared Pd/MWCNTs and with a commercial Pt–Ru/Vulcan catalyst. The catalysts were prepared by a two‐stage polyol method, followed by H2–Ar annealing and were characterised by using X‐ray diffraction, FE‐TEM and EDX. Cyclic voltammetry (CV) was used to test their catalytic activity towards formic acid electrooxidation and accessible metal surface in the catalyst layer. In the case of the precursor of Pd–Au/MWCNTs catalyst (before H2–Ar annealing), subsequent deposition of Pd and Au led to a material of the core‐shell structure, catalytically inactive. Annealing of the core shell Pd–Au/MWCNTs precursor in H2–Ar resulted in the formation of the novel Pd–Au/MWCNTs catalyst. A highly dispersed Pd–Au solid solution (average XRD particle size 4.8 nm) is formed, and the novel catalyst is more active than the Pd/MWCNTs one. Both the Pd–Au/MWCNTs and the Pd/MWCNTs catalysts turned out to be more active than a commercial, highly dispersed Pt–Ru/Vulcan catalyst.

The hybrid nanomaterials of platinum/cerium oxide/multi-walled carbon nanotubes (Pt/CeO 2 /MWCNTs) are synthesized successfully via impregnation and polyol processes. MWCNTs serve as an excellent supporter where CeO 2 nanoparticles are decorated with well-distributed Pt nanoparticles. Images show the average particle size of crystalline Pt and CeO 2 on MWCNTs are 3À7 and 20À30 nm, respectively. In electrochemical reaction, the redox peak of Pt/CeO 2 -700 ○ C/MWCNTs reveals lower potential and higher current density in methanol electro-oxidation than those of other Pt-based ones. The study indicates that the cerium oxide in Pt/CeO 2 -700 ○ C/MWCNTs catalyst will enhance significantly the oxygen ions transportation between the interface of Pt and MWCNTs to eliminate the CO poison effect on Pt catalyst.

In the present study, pure TiO2 and hybrid TiO2/CNTs nanomaterials are prepared by sol gel technique. Post heat treatment is performed at 600, 800, and 1000 degrees C, respectively. The structural characterizations are performed by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and synchrotron X-ray absorption spectroscopy techniques. Experimental results show that anatase to rutile transformation can be observed for pure TiO2 nanomaterials after heat treatment at 800 degrees C. The anatase to rutile transformation is inhibited by carbon nanotubes, and therefore only anatase phases for TiO2 nanomaterials can be observed in the hybrid nanomaterials. The 600 degrees C hybrid nanomaterials show a microstructure with CNTs covered by continuous TiO2 films of numerous small nanoparticles. After applying heat treatment on the hybrid nanomaterials at 1000 degrees C, only TiO2 nanoparticles adhere individually to the uncovered CNTs. Though all hybrid nanomaterials exhibit anatase TiO2, synchrotron X-ray absorption spectra investigations reveal that hybrid TiO2/CNTs exhibit different electronic properties as compared to those of pure TiO2 nanomaterials.