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The electrooxidation of methanol – the anodic reaction of direct methanol fuel cells – suffers from slow kinetics. Here, we report an enhanced current density for a Pt catalyst supported on nitrogen‐doped carbon nanotube (N−CNT) decorated FeP. X‐ray photoelectron spectra show that the introduction of FeP increases the binding energy of the Pt nanoparticles. The results show that Pt/FeP15%/N−CNT displays a 3.4 times higher forward peak current density compared to commercial Pt/C. The improved performance is attributed to a change in the electronic state of the Pt nanoparticles through the electronic interaction between Pt and FeP, evidenced by the mitigated CO poisoning. [ABSTRACT FROM AUTHOR]

Abstract: Phosphorus-doped multiwalled carbon nanotubes (MCNTs) were synthesized by the thermolysis and characterized by electron microscopy and microanalysis technique and evaluated with electrochemical methods. The results revealed that carbon nanotube length became shorter, the tube diameters increased and the yield of MCNTs reduced gradually with the increase of the concentration of triphenylphosphine in toluene solution, and the tube diameters increased with the increase of the synthesis temperature. Moreover, the phosphorus doping significantly improved the electrocatalytic activity of carbon nanotubes for the oxygen-reduction reaction in alkaline media, and the carbon nanotubes doped with small amounts of phosphorus exhibited higher electrocatalytic activity and stability than Pt/C catalyst. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Carbon nanotube immobilized IrO2 (IrO2/CNT) was prepared by a simple oxidation method with hydrogen peroxide as an oxidant and used as an improved catalyst support to load active Pt to prepare Pt/IrO2/CNT anode catalyst for direct methanol fuel cell. Electrochemical measurement revealed that Pt/IrO2/CNT exhibits much higher activity for methanol oxidation and better CO tolerance than Pt/CNT. The anodic peak current of methanol oxidation on Pt/IrO2/CNT (873.1A gPt −1) is 2.6 times that of Pt/CNT catalyst (335.7A gPt −1). The enhanced performance of Pt/IrO2/CNT is attributed to the fact that IrO2 improves the dispersion of Pt nanoparticles, and lowers the charge transfer resistance in methanol electrooxidation. [Copyright &y& Elsevier]

Abstract: Phosphorus-doped multiwalled carbon nanotubes (P-MCNTs) were synthesized by thermolysis and employed as supports to prepare Pt/P-MCNTs catalyst for direct methanol fuel cells (DMFCs). Pt/P-MCNTs exhibited much higher electrocatalytic activity and longer-term stability for methanol oxidation than Pt/MCNTs in acidic medium, due to the higher dispersion and utilization rate and the improvement of intrinsic activity for methanol oxidation of Pt nanoparticles, indicating a highly potential application of Pt/P-MCNTs in DMFCs. [Copyright &y& Elsevier]

To decrease the high cost of cathodic electrocatalysts caused by platinum-based catalysts in fuel cells, a series of silicon-doped carbon nanotubes with different Si contents were synthesized by the thermolysis of trimethylphenylsilane and xylene and used as low-cost metal-free catalysts for the oxygen reduction reaction (ORR). Electrochemical tests showed that the electrocatalytic activities of the synthesized Si-doped carbon nanotubes towards the ORR all were higher than that of pure carbon nanotubes and their ORR activities did not enhance proportionally with the increase of silicon doping content in alkaline medium, indicating a promising potential for designing low-cost and efficient metal-free electrocatalysts in future alkaline fuel cell devices. [ABSTRACT FROM AUTHOR]

Nitrogen doped carbon nanotubes (NCNTs) with encapsulated Fe 3 C nanoparticles (Fe 3 C@NCNTs) are synthesized by a simple direct pyrolysis of melamine and ferric chloride. The characterization results reveal that Fe 3 C is mainly encapsulated in the interior of NCNTs and N species is mainly distributed on the outside surface of NCNTs. Iron and iron carbide catalyze the growth of NCNTs and are wrapped by carbon to form Fe 3 C@NCNTs. The as-prepared Fe 3 C@NCNTs catalyst exhibits superior oxygen reduction reaction (ORR) activity, excellent methanol tolerance and long-term stability in both acid and alkaline media. It is proven that the doped N is the main active site for ORR and the inner Fe 3 C with outside carbon form the synergetic active site to enhance ORR activity. The ORR mechanism of direct four electron transfer pathway is proved in acid and alkaline media. [ABSTRACT FROM AUTHOR]

Abstract: The electrocatalytic performances of carbon nanotubes supported platinum (Pt/CNTs) with different Pt loadings for oxygen reduction reaction (ORR) and methanol oxidation (MOR) are studied contrastively. Pt/CNTs showed an opposite change rule along different Pt loadings for ORR and MOR, which is discussed based on the charge transportation and mass transfer. The results show that at low Pt loading, proton conduction is the key factor, which determines the MOR activity; at high Pt loading, mass transfer is crucial, which decides the ORR activity of Pt/CNT catalysts. The viewpoint proposed in this paper can guide the design and preparation of Pt based catalysts for the commercialization of direct methanol fuel cells. [Copyright &y& Elsevier]

Abstract: The oxygen reduction reaction (ORR) has been investigated on fish-bone carbon nanotubes (F-CNTs) and parallel carbon nanotubes (P-CNTs). The results showed that the F-CNTs exhibited much higher activity than P-CNTs, which originated from the higher fraction of edge carbon atoms. The dependence of ORR peak potential on the fraction of edge carbon atoms was determined quantitatively for the first time. The density functional theory calculations clearly unveiled the mechanism of edge carbon atoms facilitating the ORR performance. [Copyright &y& Elsevier]