Enhanced CO Oxidation and Cyclic Activities in Three-Dimensional Platinum/Indium Tin Oxide/Carbon Black Electrocatalysts Processed by Cathodic Arc Deposition

Abstract

There have been extensive efforts to develop competitive electrocatalysts using carbon black (CB) supports for high-performance proton-exchange membrane fuel cells with less usage of Pt. Herein, we propose a very promising electrocatalyst architecture based on the three-dimensional Pt/indium tin oxide (ITO)/CB support structure which was enabled by a nonconventional deposition process ensuring very uniform impregnation of Pt and ITO nanoparticles into the CB network. The unusual scales of the Pt (∼1.9 nm) and ITO (∼5.6 nm) nanoparticles were directly related to unexpectedly better performance of the electrocatalytic activities. As a highlight, the electrochemical surface area of the electrocatalyst was maintained very well after the 3000 cycle-accelerated durability evaluation by demonstrating an excellent retention of ∼74.9%. Particularly, the CO tolerance exhibited a low value of ∼0.68 V as the absorption current peak, compared to ∼0.79 V for a commercial Pt/CB catalyst containing twice more Pt.

Developments and Perspectives on Robust Nano‐ and Microstructured Binder‐Free Electrodes for Bifunctional Water Electrolysis and Beyond

“…In addition, the deposition of Pt NPs on ITO has been exploited for electrocatalytic processes. [247][248][249] The immobilization of metallic NPs on a porous ITO electrode has been employed for Ir and Ru. [250] In addition, Lebedev and Copéret [250] demonstrated a facile solution method for the immobilization of small and narrowly distributed Iridium NPs (1.5 nm) on a conductive ITO support (Ir NPs -ITO) for water oxidation under acidic conditions.…”

Controlled Synthesis of Carbon-Supported Pt-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

“…Table 4 shows some methods for preparing carbon–metal oxide composite supports by depositing metal oxides as particles onto carbon. Pt-based electrocatalysts with carbon–metal oxide composite supports generally show improved electrocatalytic activity [ 140 ] and enhanced durability [ 129 , 133 ] due to the enhanced metal–support interaction. Metal oxide nanoparticles also act as a physical barrier, which decreases the chance of Pt-based nanoparticles encountering each other to a certain extent, thereby enhancing the durability.…”

“…Moreover, the affinity of Pt-based electrocatalysts with carbon is weak, easily resulting in the migration and coalescence of Pt-based electrocatalysts [132]. Compared with carbon materials, metal oxides, such as indium tin oxide (ITO) [133], CeO 2 [134], TiO 2 [135], SnO 2 [136], NbO x [137], WO 3 [138], and Mn 3 O 4 [139], commonly have higher stabilities in oxidative and high-potential environments. The strong metal-metal oxide interaction can effectively mitigate the degradation of Pt-based electrocatalysts.…”

“…Metal oxide nanoparticles also act as a physical barrier, which decreases the chance of Pt-based nanoparticles encountering each other to a certain extent, thereby enhancing the durability. In addition, the CO tolerance of Pt-based electrocatalysts is improved because the CO adsorbed on Pt-based electrocatalysts can be easily oxidized by the oxygen-containing species that are supplied by the metal oxides [133,134,140]. Figure 6a exhibits three scenarios for Pt-based nanoparticles deposited on composite supports with a large metal oxide particle size, i.e., only on the carbon surface (particle 1), only on the metal oxide surface (particle 2) or at junctions between metal oxide particles and carbon (Pt-based nanoparticles that simultaneously contact carbon and metal oxides to form triple junctions, particle 3).…”

Synergistic effects in bimetallic Pd–CoO electrocatalytic thin films for oxygen evolution reaction

“…The result is the high over-potentials, and low current densities, whereas the target is to achieve an industrial standard current density of more than 100 mA cm −2 with the least over-potential possible 4 . Thus, the materials with the ability to catalyze this reaction are of high significance not only for water splitting based hydrogen generation 5 , 6 , but also for oxygen evolution reactions (OER) in metal-air batteries 7 , 8 , or other oxidation reactions such as the oxidation of CO 9 for the purification of hydrogen fuel obtained via currently accustomed fossil fuels based production. While the oxides of Iridium and Ruthenium still remains the benchmark in catalyzing this process 10 , the search for the earth-abundant low-cost substitute continues 5 , 11 .…”