Development of a Bifunctional Ti-Based Gas Diffusion Electrode for ORR and OER by One- and Two-Step Pt-Ir Electrodeposition

Abstract

The present paper presents one- and two-step approaches for electrochemical Pt and Ir deposition on a porous Ti-substrate to obtain a bifunctional oxygen electrode. Surface pre-treatment of the fiber-based Ti-substrate with oxalic acid provides an alternative to plasma treatment for partially stripping TiO2 from the electrode surface and roughening the topography. Electrochemical catalyst deposition performed directly onto the pretreated Ti-substrates bypasses unnecessary preparation and processing of catalyst support structures. A single Pt constant potential deposition (CPD), directly followed by pulsed electrodeposition (PED), created nanosized noble agglomerates. Subsequently, Ir was deposited via PED onto the Pt sub-structure to obtain a successively deposited PtIr catalyst layer. For the co-deposition of PtIr, a binary PtIr-alloy electrolyte was used applying PED. Micrographically, areal micro- and nano-scaled Pt sub-structure were observed, supplemented by homogenously distributed, nanosized Ir agglomerates for the successive PtIr deposition. In contrast, the PtIr co-deposition led to spherical, nanosized PtIr agglomerates. The electrochemical ORR and OER activity showed increased hydrogen desorption peaks for the Pt-deposited substrate, as well as broadening and flattening of the hydrogen desorption peaks for PtIr deposited substrates. The anodic kinetic parameters for the prepared electrodes were found to be higher than those of a polished Ir-disc.

Design of Ir/Pt dual electrocatalysts loaded on exfoliated acetylene black for Li air battery application

“…These findings highlight the potential of the new catalyst for application in Li-air batteries and its promising performance. This study employs a bimetallic nanoalloy, with one metal works for ORR while the other metal works for OER under a metal oxide state [44,46].…”

“…OER corresponds to Li 2 O 2 decomposition, and ORR is corresponding to the Li 2 O 2 formation [12,13,28]. This observation could be due to the formation of more active IrO 2 [44,45,58]. The CV results indicate that Li-air battery should be capable of showing cycles in stable manner.…”

“…A significant body of literature exists on the synthesis of core-shell nanoparticles on carbon using diverse methods, including wet chemical methods [38,39], spontaneous deposition [40], and redox displacement techniques involving underpotential deposition [32], offering a wide range of approaches for the fabrication of these hybrid structures. Existing research on Pt/IrO 2 nanoparticles has suggested that it is not desirable to have extremely small particle sizes, and that it is challenging to maintain both metals in an alloyed state within the system [41][42][43][44][45][46]. Under the research background of bifunctional catalyst, maintaining OER activity is challenging.…”

“…The purpose of the current study is to understand the activity of bifunctional Pt and Ir on FAB (Functionalized Acetylene Black) based carbon support, which has demonstrated good performance in either ORR with Pt-C or OER with IrO 2 -C [44,[46][47][48][49][50]. FAB as a carbon-support for Pt material showed promise as a cathodic electrocatalyst material for the oxygen reduction reaction [51].…”

Self-Templating Synthesis of N/P/Fe Co-Doped 3D Porous Carbon for Oxygen Reduction Reaction Electrocatalysts in Alkaline Media

“…Generally, the catalytic performance of carbon-based doped catalysts depends on the specific surface area and pore structure, the composition, content, and distribution of doped elements [18][19][20][21]. Conventional synthetic techniques are mainly obtained by porous templates at high carbonization temperatures [22,23].…”