Stable and Active Oxygen Reduction Catalysts with Reduced Noble Metal Loadings through Potential Triggered Support Passivation

Abstract

The development of stable, cost‐efficient and active materials is one of the main challenges in catalysis. The utilization of platinum in the electroreduction of oxygen is a salient example where the development of new material combinations has led to a drastic increase in specific activity compared to bare platinum. These material classes comprise nanostructured thin films, platinum alloys, shape‐controlled nanostructures and core–shell architectures. Excessive platinum substitution, however, leads to structural and catalytic instabilities. Herein, we introduce a catalyst concept that comprises the use of an atomically thin platinum film deposited on a potential‐triggered passivating support. The model catalyst exhibits an equal specific activity with higher atom utilization compared to bulk platinum. By using potential‐triggered passivation of titanium carbide, irregularities in the Pt film heal out via the formation of insoluble oxide species at the solid/liquid interface. The adaptation of the described catalyst design to the nanoscale and to high‐surface‐area structures highlight the potential for stable, passivating catalyst systems for various electrocatalytic reactions such as the oxygen reduction reaction.

2D noble metals: growth peculiarities and prospects for hydrogen evolution reaction catalysis

“…However, since the height of the Pt islands/clusters is controllable (up to the reaching of the 0.13 nm 84 ) they are of interest to catalytic applications in their own way. Concomitantly, ALD technique was found to be the more effective method to form continuous ultrathin Pt layers on graphene oxide 87 and titanium carbide (TiC) 88 , respectively. For example, the use of MeCpPtMe 3 as a Pt precursor and ozone as a co-reactant enabled the formation of stable Pt films with thicknesses ranging from 1 to 6 monolayers 88 .…”

“…Concomitantly, ALD technique was found to be the more effective method to form continuous ultrathin Pt layers on graphene oxide 87 and titanium carbide (TiC) 88 , respectively. For example, the use of MeCpPtMe 3 as a Pt precursor and ozone as a co-reactant enabled the formation of stable Pt films with thicknesses ranging from 1 to 6 monolayers 88 .…”

“…For example, the use of MeCpPtMe 3 as a Pt precursor and ozone as a co-reactant enabled the formation of stable Pt films with thicknesses ranging from 1 to 6 monolayers. 88 Surface-limited redox replacement (SLRR) is another promising approach to form a Pt bilayer or monolayer on graphene 89 or gold. 90 The core of this method is based on the galvanic displacement on a underpotentially deposited (UPD) Cu layer (sacrificial metal) by the platinum.…”

“…For example, the use of MeCpPtMe 3 as a Pt precursor and ozone as a co-reactant enabled the formation of stable Pt films with thicknesses ranging from 1 to 6 monolayers. 88…”

New challenges in oxygen reduction catalysis: a consortium retrospective to inform future research

“…36 This disproportionate dissolution indicated that the performance losses observed for CS NPs were all due to the dissolution of CS NP particles with imperfect Pt surface coverage, suggesting that the stability of Pt/TiWC catalysts could be improved with enhanced synthetic methods to achieve complete coverage of the labile TiWC cores. 36 In addition to achieving complete Pt coverage, the stability of CS NP catalysts could be optimized for ORR in future work through the incorporation of more stable core materials 101 or additional phases such as phosphides. 102…”