Grain boundary engineering for efficient and durable electrocatalysis.

Grain boundaries in noble metal catalysts have been identified as critical sites for enhancing catalytic activity in electrochemical reactions such as the oxygen reduction reaction. However, conventional methods to modify grain boundary density often alter particle size, shape, and morphology, obscuring the specific role of grain boundaries in catalytic performance. This study addresses these challenges by employing gold nanoparticle assemblies to control grain boundary density through the manipulation of nanoparticle collision frequency during synthesis.

Concave Grain Boundaries Stabilized by Boron Segregation for Efficient and Durable Oxygen Reduction.

The oxygen reduction reaction (ORR) is a critical process that limits the efficiency of fuel cells and metal-air batteries due to its slow kinetics, even when catalyzed by platinum (Pt). To reduce Pt usage, enhancing both the specific activity and electrochemically active surface area (ECSA) of Pt catalysts is essential. Here, ultrafine, grain boundary (GB)-rich Pt nanoparticle assemblies are proposed as efficient ORR catalysts.

Unraveling the Evolution of Dynamic Active Sites of LaNiFeO Catalysts During OER.

Perovskites have attracted tremendous attention as potential catalysts for the oxygen evolution reaction (OER). It is well-known that the introduction of Fe into rare earth perovskites such as LaNiO enhances the intrinsic OER activity. Despite numerous studies on structure-property relationships, the origin of the activity and the nature of the active species are still elusive and unclear.

Expanding the Potential of Identical Location Scanning Transmission Electron Microscopy for Gas Evolving Reactions: Stability of Rhenium Molybdenum Disulfide Nanocatalysts for Hydrogen Evolution Reaction.

Identical location (scanning) transmission electron microscopy provides valuable insights into the mechanisms of the activity and degradation of nanocatalysts during electrochemical reactions. However, the technique suffers from limitations that hinder its widespread use for nanocatalysts of gas evolving reactions, e.g.

Electrochemical Stability of Rhodium-Platinum Core-Shell Nanoparticles: An Identical Location Scanning Transmission Electron Microscopy Study.

Rhodium-platinum core-shell nanoparticles on a carbon support (Rh@Pt/C NPs) are promising candidates as anode catalysts for polymer electrolyte membrane fuel cells. However, their electrochemical stability needs to be further explored for successful application in commercial fuel cells. Here we employ identical location scanning transmission electron microscopy to track the morphological and compositional changes of Rh@Pt/C NPs during potential cycling (10 000 cycles, 0.

Insights into the performance and degradation of Ru@Pt core-shell catalysts for fuel cells by advanced (scanning) transmission electron microscopy.

Ru@Pt core-shell nanoparticles are currently being explored as carbon monoxide tolerant anode catalysts for proton exchange membrane fuel cells. However, little is known about their degradation under fuel cell conditions. In the present work, two types of Ru@Pt nanoparticles with nominal shell thicknesses of 1 (Ru@1Pt) and 2 (Ru@2Pt) Pt monolayers are studied as synthesized and after accelerated stress tests.

Evaluation of functional layers thinning of high temperature polymer electrolyte membrane fuel cells after long term operation.

The operation related degradation processes of high temperature polymer electrolyte membrane fuel cell operated with hydrogen-rich reformate gas are studied. CO impurities from the reformate gas are strongly adsorbed by the catalyst surface, leading to poisoning and thus, reduction of the overall performance of the cell. Most of the studies are performed in a laboratory set-up by applying accelerated stress tests.