Oxide–Carbon Nanofibrous Composite Support for a Highly Active and Stable Polymer Electrolyte Membrane Fuel-Cell Catalyst

Abstract

Well-designed electronic configurations and structural properties of electrocatalyst alter the activity, stability, and mass transport for enhanced catalytic reactions. We introduce a nanofibrous oxide-carbon composite by an in situ method of carbon nanofiber (CNF) growth by highly dispersed Ni nanoparticles that are exsoluted from a NiTiO surface. The nanofibrous feature has a 3D web structure with improved mass-transfer properties at the electrode. In addition, the design of the CNF/TiO support allows for complex properties for excellent stability and activity from the TiO oxide support and high electric conductivity through the connected CNF, respectively. Developed CNF/TiO-Pt nanofibrous catalyst displays exemplary oxygen-reduction reaction (ORR) activity with significant improvement of the electrochemical surface area. Moreover, exceptional resistance to carbon corrosion and Pt dissolution is proven by durability-test protocols based on the Department of Energy. These results are well-reflected to the single-cell tests with even-better performance at the kinetic zone compared to the commercial Pt/C under different operation conditions. CNF/TiO-Pt displays an enhanced active state due to the strong synergetic interactions, which decrease the Pt d-band vacancy by electron transfer from the oxide-carbon support. A distinct reaction mechanism is also proposed and eventually demonstrates a promising example of an ORR electrocatalyst design.

An opinion on catalyst degradation mechanisms during catalyst support focused accelerated stress test (AST) for proton exchange membrane fuel cells (PEMFCs)

“…The lower ECSA loss may be attributed to the higher scan rate, leading to lower particle growth [33]. The ECSA loss of the present study may also be compared with that by Joen et al, suggesting ~70% ECSA loss during AST of Pt/C (40 wt.% Pt) for 6000 cycles at a scan rate of 100 mV/s between 1.0 and 1.6 V in 0.5 M H2SO4 [34]. Fig.…”

Enhancement of Catalytic Activity and Durability of Pt Nanoparticle through Strong Chemical Interaction with Electrically Conductive Support of Magnéli Phase Titanium Oxide

“…To alleviate the negative effects of the amorphous carbon deterioration, corrosionresistant carbon supports; CNT [7,8], CNF [9], and graphene [10,11], heteroatom doped carbon [12] and also metal oxide supports have been introduced in the literature [13][14][15][16][17][18]. Among varied metal oxides [19][20][21], TiO 2 draws prominent attention because of high chemical-durability and good corrosion-resistance under PEFCs operation. In addition, the hypo d-electron character of TiO 2 enables its interaction with Pt, known as a strong metal support interaction (SMSI), thus changing the catalytic activity of the noble metal [22][23][24][25].…”

Ultrafine Pt nanoparticles supported on double-shelled C/TiO2 hollow spheres material as highly efficient methanol oxidation catalysts

“…Based on the calculation of density functional theory, TiO 2 has been considered as one of the most promising catalyst supports. The experimental results demonstrated that the strong metal-support interactions between Pt and TiO 2 can improve the catalytic performance [17] .…”

“…To reduce the dependence on precious metal and avoid the poisoning effect, catalyst supports consisting of carbon materials [7 , 8] and transition metal oxides (SiO 2 [9 , 10] , SnO 2 [11] , TiO 2 [12][13][14] , CeO 2 [15] are extensively studied. Among them, oxides play a critical role owing to their charge transfer phenomena [16] and the ability to inhibit the dissolution of Pt [17] . Based on the calculation of density functional theory, TiO 2 has been considered as one of the most promising catalyst supports.…”