Investigation of iridium composition in Ti1–xIrxO2 (x = 0.1, 0.2, 0.3) nanostructures as potential supports for platinum in methanol electro-oxidation

Abstract

To overcome the disadvantages of commercial carbonaceous catalysts in direct methanol fuel cells (DMFCs), novel Pt/Ti 1ex Ir x O 2 catalysts are fabricated in this study. Simultaneously, the influence of the Ir composition in the support on the electrocatalytic activities and physicochemical properties of Pt/Ti 1ex Ir x O 2 catalysts is also evaluated. Ti 1ex Ir x O 2 materials with the tunable Ir composition (x ¼ 0.1, 0.2, 0.3) synthesized via a simple and green hydrothermal route exhibited much higher electrical conductivity and surface area than the undoped TiO 2 . Furthermore, the well-distributed Pt nanoparticles (NPs) with small sizes (~3 nm) over supports were obtained by using a modified chemical reduction route. Electrochemical results revealed that a series of 20 wt. % Pt/Ti 1ex Ir x O 2 catalysts exhibited superior durability and electrochemical activity toward the methanol oxidation reaction to the commercial 20 wt. % Pt/C (E-TEK) catalyst. According to these results, Ti 1ex Ir x O 2 materials seem to be very promising as a stable catalyst support in the harsh medium of DMFCs.

Synthesis and characterization of Ti0.9Ir0.1O2-activated carbon composite as a promising support for catalysts in electrochemical energy conversion

“…Detailly, CV curves of Ti 0.9 Ir 0.1 O 2 , Ti 0.9 Ir 0.1 O 2 -Activated C (75:25 wt%), Ti 0.9 Ir 0.1 O 2 -Activated C (50:50 wt%) exhibited the negligible change after ADT, while the different shape before and after ADT was observed in CV curves of Ti 0.9 Ir 0.1 O 2 -Activated C (25:75 wt%), and Vulcan XC-72. The redox reaction on CV curves of the Ti 0.9 Ir 0.1 O 2 -Activated C (25:75 wt%) and Vulcan XC-72 supports was assigned to the formation of surface oxide due to a hydroquinone-quinone (HQ-Q) redox couple on the carbon black surface [34][35][36], indicating the poor electrochemical corrosion resistance of carbon black in acidic long-term operating conditions.…”

Low‐dose Ir‐doped TiO 2 supported Pt‐Co bimetallic nanoparticles: A highly active and CO‐tolerant electrocatalyst towards methanol oxidation reaction

“…The fall in mass activity of catalysts with time results from the surface active site poisoning phenomenon by intermediates generated from incomplete methanol oxidation 12b . Notably, for the Pt‐Co alloy, this detrimental effect is not significant because Co sites and the Ti 0.9 Ir 0.1 O 2 support may contribute to blocking poisoning compound adsorption by producing OH groups for CO oxidation via the ligand effect 4,16,43 . Moreover, the strong interaction between the alloy catalyst and TiO 2 ‐based support also assists in lessening the CO‐Pt bond, thus benefiting the stability improvement of the Pt 3 Co 1 /Ti 0.9 Ir 0.1 O 2 catalyst compared with the Pt/C catalyst 44 .…”

“…Thus, replacing carbonaceous supports with more resistant materials also plays a crucial role in this strategy. Pt‐group metal‐doped conductive metal oxide materials in general, and Ir‐doped TiO 2 materials in particular, have a wide range of important applications such as supports for fuel cell electrocatalysts 17 or photocatalysts for wastewater or exhausted gas treatment 18 . Noticeably, Ti 0.9 Ir 0.1 O 2 material developed by our team 19 can show appealing features like high electrical conductivity, good corrosion resistance and strong metal‐support interaction, which not only meet requirements for a good electrocatalyst support 20 but also outperform commonly‐used carbonaceous supports.…”