Pt/MnO2/carbon nanotube (CNT) and PtRu/MnO2/CNT nanocomposites were synthesized by successively loading hydrousMnO2 and Pt (or PtRu alloy) nanoparticles on CNTs and were used as anodic catalysts for direct methanol fuel cells (DMFCs). The existence of MnO2 on the surface of CNTs effectively increases the proton conductivity of the catalyst, which then could remarkably improve the performance of the catalyst in methanol electro-oxidation. As a result, Pt/MnO2/CNTs show higher electrochemical active surface area and better methanol electro-oxidation activity, compared with Pt/CNTs. As PtRu alloy nanoparticles were deposited on the surface of MnO2/CNTs instead of Pt, the PtRu/MnO2/CNT catalyst shows not only excellent electro-oxidation activity to methanol with forward anodic peak current density of 901 A/gPt but also good CO oxidation ability with lower preadsorbed CO oxidation onset potential (0.33 V vs Ag/AgCl) and peak potential (0.49 V vs Ag/AgCl) at room temperature.

NaxBayBiO3·nH2O (NBBO) has been prepared using a commercial NaBiO3·nH2O (NBO) as a starting material with a hydrothermal iron-exchange reaction. As-synthesized samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible light (UV–vis) absorbance spectra, thermogravimetry-differential scanning calorimetry (TG-DSC) and X-ray photoelectron spectroscopy (XPS) techniques. The photooxidation decomposition of phenol over NBBO has been carried out under visible-light irradiation (λ> 400 nm). The result revealed that the NBBO showed considerable photooxidation activity for phenol degradation in the range of visible light. The result of reusability indicated the structure of NBBO was instable, which was changed to Bi2O2CO3 in the photooxidation process, although photooxidation activity kept high in three runs. This study has provided useful information for the development of new bismuthate photocatalyst with higher photoactivity under visible-light irradiation.

The activity of RuO2 xH2O/CNT for benzyl alcohol oxidation can be predicted by the specific capacitance (SC) of RuO2, suggesting that highly active RuO2 nanocatalysts are also good supercapacitor materials with SC high up to 1500 F gRuO2 1.

Pt/CNTs, PtRu/CNTs, Pt/RuO2/CNTs and RuO2/Pt/CNTs were prepared to understand the role of RuO2 in anodic catalyst of direct methanol fuel cell (DMFC). The results show that the presence of Ru, no matter in alloy or in oxide, can improve the CO electrooxidation ability. RuO2 in Pt-Ru binary catalyst, which situates between CNTs and Pt particles, can exert its CO electrooxidation ability best. Another role of RuO2 in Pt-Ru binary catalyst is to promote Pt nanoparticles to disperse uniformly on CNTs to obtain larger EAS, resulting in higher activity of methanol electrocatalytic oxidation.

Both substitutional and interstitial nitrogen-doped titanium dioxides (N-TiO2) were prepared. Their surface states were clarified by XPS spectra of N 1s, O 1s and Ti 2p. The results of photocatalysis show that both substitutional and interstitial N impurities greatly enhance the photoactivity of TiO2 in visible light. Moreover, the visible light activity of interstitial N-doped TiO2 is higher than that of substitutional N-doped TiO2. The microwave synthesis presented in this paper is a promising and practical method to produce interstitial nitrogen-doped photocatalysts with high visible light activity.

Nitrogen-doped TiO2 (N-TiO2) nanoparticles have been successfully prepared via a direct and simple hydrothermal reaction of a commercial Degussa P25 with triethanol amine as solvent and nitrogen source. As-prepared N-TiO2 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible light (UV–vis) absorption spectra, electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS) techniques. The results confirm that hydrothermal reaction is an effective way to incorporate nitrogen into the TiO2 lattice, especially nitrogen substitute for titanium. The nitrogen concentration in TiO2 can be as high as 21% (molar ratio), which is described as Ti1-yO2-xNx+y (in this paper,x=0.36, y=0.27, i.e., Ti0.73O1.64N0.63). The chemical statuses of N have been assigned to N-Ti-O and O-N-O in the TiO2 lattice as identified by XPS. Photocatalytic degradation of methyl orange has been carried out in both UV-vis (simulated solar light) and the visible region (λ>4400 nm). N-TiO2 exhibits higher activity than the Degussa P25 TiO2 photocatalyst, particularly under visible-light irradiation. This study has developed a promising and practical pathway to new nitrogen-doped photocatalysts.

The nitric acid oxidation followed by sodium hydroxide washing was applied for functionalization of singlewalled carbon nanotubes (SWCNTs), few-walled CNTs (FWCNTs), and multiwalled CNTs (MWCNTs). The surface functionalization of CNTs via acidic oxidation was studied by transmission electron microscopy, Raman scattering spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The oxidation of CNTs involves the exfoliation of functionalized carbon layers into smaller carbonaceous fragments (CF), which might influence the performance of composite materials based on modified CNTs. Optimizing oxidation time increased the selectivity to thermodynamically unstable functionalized CNTs. Thicker CNTs, including FWCNTs and MWCNTs, are better for high-density surface functionalization, due to higher structure stability. It was proposed that a rational selection of the oxidation process and type of CNTs is important for the applications involving CNT-related composite materials.

Highly dispersed ruthenium oxide clusters were synthesized on carbon nanotubes (CNTs) to form RuO2·xH2O/ CNT catalyst by a homogeneous oxidation precipitation method. Methanol oxidation was carried out on RuO2·xH2O/CNT at low temperatures for the production of diverse oxygenous products, such as methyl formate (MF) and dimethoxymethane (DMM). Unprecedented conversion rate of methanol, high up to 545 molMeOH (mol Rusurface)-1 h-1, was observed at 120 ℃. The effect of structural water in RuO2 domains on the performances of the methanol oxidation reaction was investigated by annealing them in N2 at elevated temperatures. The dehydration of RuO2 clusters decreased the oxidation ability and changed the selectivity patterns. It was suggested that the behaviors of RuO2 during the annealing process may be strongly influenced by the interaction between RuO2 and CNTs.

Nanoboxes, nanocubes and nanospheres of cuprous oxides were readily synthesized by reducing Cu(CH3COO)2 H2O with ethylene glycol at different concentrations of poly(vinyl pyrrolidone); the formation mechanism of as-synthesized Cu2O nanostructures was investigated. Moreover, we report the highly selective adsorption characteristic of as-synthesized Cu2O nanostructures to anionic dyes and suggest the mechanism is electrostatic adsorption.

Ruthenium(Ⅳ) oxide (RuO2) nanoparticles supported by herringbone carbon nanotubes (CNTs) were synthesized by a homogenous-oxidationprecipitation (HOP) method with H2O2. The morphology and composition of the resulting composite were characterized by TEM, XPS, XRD, TG and TPR. CNTs exhibited the better ability to induce the formation of highly dispersed nanoparticles, compared with common used supports, such as g-Al2O3 and activated carbon. Amorphous hydrous RuO2 nanoparticles uniformly dispersed on the surface of CNTs. The average size of RuO2 was significantly reduced to 1.35 nm. This result leads to the high activity and excellent selectivity, which has been demonstrated in the aerobic oxidation of alcohols to aldehydes or ketones. The new preparation technique of CNT-supported oxide nanoparticles reported in this paper has great potential for various catalytic applications.