Electrode coatings from sprayed titanium dioxide nanoparticles – behaviour in NaOH solutions

Electrospun Nb-doped TiO2 nanofiber support for Pt nanoparticles with high electrocatalytic activity and durability

This study explores a facile method to prepare an efficient and durable support for Pt catalyst of polymer electrolyte membrane fuel cell (PEMFC). As a candidate, Nb-doped TiO₂ (Nb-TiO₂) nanofibers are simply fabricated using an electrospinning technique, followed by a heat treatment. Doping Nb into the TiO₂ nanofibers leads to a drastic increase in electrical conductivity with doping level of up to 25 at. % (Nb_0.25Ti_0.75O₂). Pt nanoparticles are synthesized on the prepared 25 at. % Nb-doped TiO₂-nanofibers (Pt/Nb-TiO₂) as well as on a commercial powdered carbon black (Pt/C). The Pt/Nb-TiO₂ nanofiber catalyst exhibits similar oxygen reaction reduction (ORR) activity to that of the Pt/C catalyst. However, during an accelerated stress test (AST), the Pt/Nb-TiO₂ nanofiber catalyst retained more than 60% of the initial ORR activity while the Pt/C catalyst lost 65% of the initial activity. The excellent durability of the Pt/Nb-TiO₂ nanofiber catalyst can be attributed to high corrosion resistance of TiO₂ and strong interaction between Pt and TiO₂.

Mesoporous titanium and niobium nitrides as conductive and stable electrocatalyst supports in acid environments

Mesoporous TiN and NbN synthesized using a block copolymer self-assembly are evaluated for catalyst support applications in acid environments.

Nanoporous Platinum Electrodes as Substrates for Metal Oxide-Supported Noble Metal Electrocatalytic Nanoparticles: Synergistic Effects During Electrooxidation of Ethanol

Electrocatalytic oxidation of ethanol in acid medium (0.5 mol dm–3 H2SO4) was significantly enhanced by not only supporting bimetallic PtRu nanoparticles on nanostructured metal oxides (TiO2 or WO3), but also by depositing such catalytic systems on planar nanoporous platinized electrode substrates. Incorporation of TiO2 or WO3 into the electrocatalytic interface was likely to improve proton mobility and to provide –OH groups capable of inducing the removal of poisoning species, such as CO, from the Pt sites in the bimetallic PtRu catalyst. Synergistic interactions between ruthenium and titania were also possible. Regularly porous nanostructured platinum substrate also permitted development of submicro ‘reactors’ where reactant molecules, electrolyte ions, and all active components (TiO2 or WO3, Pt substrate, PtRu catalytic sites) could co-exist and become easily accessible. While WO3 was able to undergo fast reversible redox transitions to non-stoichiometric oxides, efficient utilization of inert (non-electroactive) TiO2 required admixing with carbon nanotubes to ensure easy charge distribution and good conductivity at the electrocatalytic interface.

Determination of thiol compounds in rat striatum microdialysate by HPLC with a nanosized CoHCF-modified electrode

A cobalt hexacyanoferrate (CoHCF) nanoparticle (size ca. 60 nm) chemically modified electrode (CME) was fabricated and the electrochemical behavior of thiols at this nanosized CoHCF CME was studied. In comparison with a bare glassy carbon (GC) electrode and with a general CoHCF CME which was electrode-posited in the traditional manner, the present nanosized CoHCF CME efficiently performed electrocatalytic oxidation for glutathione (GSH) and L-Cysteine (L-Cys) with relatively high sensitivity, outstanding stability, and long-life. Combined with high-performance liquid chromatography (HPLC), the nanosized CoHCF CME was used for electrochemical determination (ECD) of GSH and L-Cys. The peak currents were a linear function of concentrations in the range 2.0 x 10(-7) to 2.0 x 10(-4) mol L(-1) for both GSH and L-Cys, with detection limits of 1.2 x 10(-7) and 1.0 x 10(-7) mol L(-1), respectively. Coupled with microdialysis sampling, the HPLC-ECD system has been successfully used to assess the GSH and L-Cys content of rat striatum.