Design and Preparation of CO Tolerant Anode Electrocatalysts for PEM Fuel Cells

Abstract

Abstract

Preparation of CO-tolerant anode electrocatalysts for polymer electrolyte membrane fuel cells

“…It has been demonstrated in our previous study [27,28] that preliminary formation of the rutile-TiO 2 phase in the presence of carbon at RT is prerequisite for complete W incorporation into the rutile lattice upon reduction at 650°C. XPS measurements confirmed that the incorporated tungsten was predominantly in the oxidation state of +4 [27,28]. Synthesis route A (Fig.…”

“…The leaching can not only decrease activity and CO tolerance of the catalysts but also results in reduced electrolyte performance due to metal encapsulation in the membrane. In our recent studies [27,28] x 4H 2 O, Merck, 99%) were used as tungsten and molybdenum precursor compounds. The main difference between the routes is the order of the addition of the dopant precursor and the activated carbon (CABOT, Black Pearls 2000): in route A first rutile nuclei are formed on the carbon then the dopant is introduced while in route B carbon is added to an aged colloidal solution containing both Ti and W ions.…”

Effect of Mo incorporation on the electrocatalytic performance of Ti–Mo mixed oxide–carbon composite supported Pt electrocatalysts

“…The micrographs reveal the coexistence of a few large, faceted nanorod-like mixed oxide rutile crystallites (indicated by white arrows) with the carboncontaining composite material; their presence is attributed to the relatively high mixed oxide content of the samples, as in micrographs of a composite with 50 wt% mixed oxide -50 wt% active carbon no such crystallites were observed [22,23].…”

“…The results are also summarized in Table 2. Upon preparation of the Ti 0.7 W 0.3 O 2 -C composite materials we have found [22,23] that preliminary formation of the rutile-TiO 2 phase is a necessary condition for complete isovalent W incorporation into the rutile lattice upon the following reductive treatment. Accordingly, in the course of preparation of Mo-containing composite materials, our goals were: (i) to produce Ti (1-x) Mo x O 2 rutile phase with high crystallinity and (ii) to transform of Mo into oxidation state of four.…”

Preparation and characterization of novel Ti0.7W0.3O2–C composite materials for Pt-based anode electrocatalysts with enhanced CO tolerance

“…No signal corresponding to the metallic phase of W or relevant phase separation between tungsten and titanium oxides was detected. Indeed, in our previous study it has been shown [58] that formation of the TiO 2 rutile phase before or during HTT in He before the reductive treatment is highly important in order to achieve exclusive incorporation of W into the lattice. Comparison of the results of the three synthesis routes confirms that formation of the rutile-like mixed oxide phase during annealing of an anatase-type starting material in the presence of tungsten oxides and activated carbon is highly hindered.…”