Constructing highly durable reversal-tolerant anodes via integrating high-surface-area Ti₄O₇ supported Pt and Ir@IrO_x for proton exchange membrane fuel cells

Abstract

Fuel starvation during fuel cell operation inevitably leads to high potential anodes, which causes carbon corrosion and catalyst layer collapse and poses a challenge to the durability of proton exchange...

Review of carbon-support-free platinum and non-platinum catalysts for polymer electrolyte fuel cells: will they feature in future vehicles?

“…Li et al recently synthesized fine Ti 4 O 7 particles using our carbothermal reduction reaction route with some modifications. 37 The σ -value reported in our paper 36 was well reproduced by Li et al 37 as shown by the open 36 and filled circles, 37 respectively, in Fig. 4(k).…”

“…The selected P differs across these papers, and the specific P value is not even described in some papers, making it difficult to compare the reported σ -values of non-carbon supports against each other. Some researchers reported σ at various P values, and the σ values of Ti 4 O 7 , 36–38 mixed Magnèli-phase Ti n O 2 n −1 (4 ≤ n ≤ 6), 39 commercial TiO 2 (ref. 38) and commercial carbon black 38 are compared in Fig.…”

“…The 172 m 2 g −1 BET surface area reported in our paper 36 was also well reproduced by Li et al , at 166 m 2 g −1 . 37 Micrometer-sized Ti 4 O 7 synthesized by a conventional method, annealing commercial TiO 2 powder under a reductive atmosphere (denoted as Ti 4 O 7 -L), resulted in a σ -value five orders of magnitude lower, at P = 3 MPa, two orders of magnitude lower at P = 25 MPa compared with fine Ti 4 O 7 particles. This differing dependence of σ on P may be the result of the difference in size, as shown in Fig.…”

“…Li et al succeeded in increasing the Pt mass fraction optimized for use in PEFC anodes to 40% w/w with a smaller Pt particle size (3–4 nm) and narrower size distribution than our work 36 by using an ethanol reduction method to deposit Pt nanoparticles on Ti 4 O 7 with a size of 200–300 nm. 37 The enlargement of the surface area of Ti 4 O 7 by decreasing its size produces a larger number of sites on which to deposit Pt nanoparticles. A Ti 4 O 7 particle size of approximately 100 nm will be sufficient to produce 46% w/w Pt/Ti 4 O 7 , similar to the standard Pt/C.…”

Phosphorus-Doped Pt–Ir Nanoalloy for the Improved Voltage Reversal Durability Anode in H2/O2 Fuel Cells

“…RTAs, through their unique material design and structure, can maintain stable performance even during voltage reversal, thus eliminating the need for active cell voltage monitoring. − The advancement in RTAs technology primarily involves the strategic integration of various OER catalysts, including IrO 2 , RuO 2 , TiO 2 , and IrRu. − Particularly, the integration of Ir-based catalysts has been noted for its efficiency in promoting proton and electron production at the anode through OER instead of carbon oxidation . The deployment of monodisperse IrO X on Pt/C (Pt-IrO X /C) has been instrumental in transforming RTA materials for PEMFCs − by ensuring a relative distribution of IrO X nanoparticles on the carbon support, boosting the efficiency of both Pt and IrO X . , However, employing additional Ir-based catalytic additives encounters substantial economic challenges due to their scarcity and elevated cost. − In light of the significant expenses associated with these catalysts, it is essential to devise RTAs that can operate effectively with lower amounts of OER catalysts, thereby enhancing the overall cost efficiency of these systems. − In a more progressive design, research efforts have focused on replacing Pt with multifunctional alloy catalysts that are adept at both hydrogen and oxygen reaction activities. This advancement represents a critical balance between catalytic activity and stability, especially for OER applications, marking a notable stride in RTA catalyst layer design. − However, the complexities of synthesizing these alloys and ensuring their multifunctional catalytic activity present significant technical hurdles.…”