Olaf Magnus Magnussen

The development of efficient oxygen evolution reaction (OER) catalysts requires a detailed understanding of how structural and compositional modifications influence the catalytic performance. Here, we present a high-throughput platform to induce structural and chemical modifications in Co ₃ O ₄ thin films by combining direct laser interference patterning (DLIP) with picosecond-pulsed laser defect engineering in liquids (PUDEL) and spatially resolved electrochemical screening via scanning electrochemical cell microscopy (SECCM). This approach enables the generation of spatially varying surface modifications within a single experiment, including controlled film restructuring, defect formation, and compositional changes. Localized measurements reveal that the OER activity is maximized at moderate laser fluence, where film restructuring and compositional changes occur, while excessive fluence leads to ablation and reduced performance. Despite the detectable Fe incorporation, activity trends are primarily governed by structural changes of the Co ₃ O ₄ film. This work establishes DLIP-PUDEL combined with SECCM as a platform for rapid structure–activity correlations and accelerated electrocatalyst development.

Liquid organic hydrogen carriers offer a promising route for hydrogen storage and transport. The durability of catalysts remains a major challenge in their commercial deployment. In this study, we investigate the dehydrogenation of the benzyltoluene/perhydrobenzyltoluene system under realistic conditions using model catalysts—2 nm thick Pt nanoparticles supported on an Al2O3 single crystal—embedded in a packed bed of commercial catalyst. Using operando grazing incidence X-ray diffraction, complemented by X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, and gas chromatography, we correlate structural changes in the platinum lattice with catalytic activity and operating parameters such as temperature, pressure, or position along the catalytic bed. We find that while the Pt lattice remains mainly stable parallel to the support, contraction occurs along the surface normal under certain dehydrogenation conditions. This perpendicular contraction correlates with the accumulation of coke and catalyst degradation, which can be rationalized by considering the influence of the chemisorbed reaction intermediates and the physisorbed carbonaceous deposits on the Pt strain. The lattice contraction and catalyst degradation are more pronounced downstream in the reactor and at elevated temperatures, where H2 gas is more prevalent, whereas higher pressures moderate it by favoring liquid-phase conditions. Selective sulfur poisoning leads to a pronounced restructuring of the Pt lattice, which is observed under thermal and operando reaction conditions.

Modifying copper‐based catalysts for the electrochemical reduction of CO ₂ by silver has attracted much interest as it allows to steer the catalytic selectivity toward multicarbon products. This study investigates the potential‐dependent interface structure of a silver‐decorated Cu(100) electrode under CO ₂ reduction conditions by in situ surface X‐ray diffraction. The results show that the electrode surface structure dynamically changes near the onset of the catalytic reaction. Specifically, we find an outward relaxation of the Cu surface layer, which is attributed to formation of CO intermediates, and a complex potential‐dependent change in the interfacial order. Furthermore, these changes are very reversible in fast potentiodynamic experiments, but only partly reversible after long‐term CO ₂ reduction.

Wet‐chemical processing of metals, for example, galvanic deposition, etching, and nanoparticle synthesis, usually requires complexing agents. In particular, for noble metal processing, anionic complexing species, such as halides or sulfide are indispensable. While it is known that these species strongly adsorb on metal surfaces and affect metal nucleation and growth, the detailed role of these anions in the underlying atomistic processes is less clear. Often, it is assumed that surface complexes are involved, but experimental evidence for the latter is still lacking. Here, we present direct in situ video‐rate scanning tunneling microscopy observations of gold–bromide and gold–sulfur surface complexes on Au(100) electrodes. Based on the intramolecular resolution images obtained in these studies, these species can be assigned to a dimeric planar and a linear complex. Once formed, the surfaces complexes are stable even at rather negative potentials and diffuse as molecular species on the Au surface.

Wet‐chemical processing of metals, for example, galvanic deposition, etching, and nanoparticle synthesis, usually requires complexing agents. In particular, for noble metal processing, anionic complexing species, such as halides or sulfide are indispensable. While it is known that these species strongly adsorb on metal surfaces and affect metal nucleation and growth, the detailed role of these anions in the underlying atomistic processes is less clear. Often, it is assumed that surface complexes are involved, but experimental evidence for the latter is still lacking. Here, we present direct in situ video‐rate scanning tunneling microscopy observations of gold–bromide and gold–sulfur surface complexes on Au(100) electrodes. Based on the intramolecular resolution images obtained in these studies, these species can be assigned to a dimeric planar and a linear complex. Once formed, the surfaces complexes are stable even at rather negative potentials and diffuse as molecular species on the Au surface.