Improved stability of mesoporous carbon fuel cell catalyst support through incorporation of TiO2

Abstract

The electrochemical stability of Pt deposited on mesoporous carbon, which was either applied in its unmodified state or coated with 20 wt% TiO 2 , was investigated by cyclic voltammetry in N 2 purged 0.5 M sulfuric acid. XRD analysis revealed that TiO 2 was present in the anatase phase. The mean Pt particle diameter was ∼6 and ∼4 nm for mesoporous carbon with and without TiO 2 , respectively. Pt supported on TiO 2 modified substrates was more stable than Pt supported on conventional mesoporous carbon when subjected to 1000 cycles in the potential range from 0.05 to 1.25 V vs. RHE. This was evident from the observation that the support with TiO 2 retained ∼53% of the electrochemically active surface area relative to the state observed after 100 cycles, whereas ∼33% of the active area remained in the case without TiO 2 . The oxygen reduction mass activity was identical for both fresh samples (i.e., 18 A g −1 Pt). After 1000 cycles the mass activity decreased to 10 A g −1 Pt for the case without TiO 2 , whereas with TiO 2 the deactivation was minor; i.e., the mass activity after 1000 cycles was 17 A g .

Electrochemical oxygen reduction behaviour of platinum nanoparticles supported on multi-walled carbon nanotube/titanium dioxide composites

“…The prepared catalyst support showed improved durability compared to conventional carbon support [52]. Same group reported Pt/TiO 2 /C catalyst with comparable ORR mass activity to that obtained for Pt supported on mesoporous carbon, however longterm cycling showed that incorporation of TiO 2 into the substrate matrix noticeably improved durability of the prepared catalyst material [30]. Huang et al coated CNTs by a nanolayer of TiO 2 with subsequent doping of TiO 2 with carbon and anchoring of Pt nanoparticles by ethylene glycol method [53].…”

“…While Pt acts as catalyst for carbon support corrosion process, TiO 2 component acts as inhibitor of the catalyst degradation process. Parts of the carbon surface may be mechanically protected against progressive electrochemical degradation by the presence of overlaid titania and therefore improve stability properties of the oxygen reduction reaction (ORR) catalysts [30]. Despite the poor electrical conductivity of TiO 2 , this metal oxide is frequently utilised in the design of catalytic composite materials due to possible synergistic effect between TiO 2 , carbon support and a catalyst.…”

First Insight into Fluorinated Pt/Carbon Aerogels as More Corrosion-Resistant Electrocatalysts for Proton Exchange Membrane Fuel Cell Cathodes

“…Metal oxides, such as tin and indium oxide (ITO), TiO x , SnO 2 , WO x , IrO 2 , and carbides, such as WC and W 2 C, have also been proposed as promising durable catalyst supports [16,17], and to overcome the insufficient electronic conductivity of the metal oxide, doping has been used [18,19]. Some researchers investigated TiO 2 /carbon composites [20,21] and showed that mixing carbon and TiO 2 is beneficial to the electrocatalyst durability. Nevertheless, none of these solutions are completely satisfactory on the field.…”

Enhancement of Activity and Durability through Cr Doping of TiO2 Supports in Pt Electrocatalysts for Oxygen Reduction Reactions

“…[11][12][13] For this reason, metal oxides have been considered as an alternative support to carbon to prevent corrosion at the cathode. [14][15][16][17] Among various candidates, TiO 2 is the most popular support material, because it is highly stable in acidic media and displays a well-known strong metal-support interaction with Pt. [18][19][20] Moreover, TiO 2 is relatively cheap and readily available in the commercial market compared with other transitionmetal oxides.…”