Evolution of surface and bulk structure of supported palladium nanoparticles by in situ X-ray absorption and infrared spectroscopies: Effect of temperature, CO and CH4 gas

High-Quality In Situ X-ray Absorption Spectroscopy Monitoring of the Palladium Nucleation inside the 3D Printed Microfluidic Chip

“…It should also be noted that the Pd–Pd interatomic obtained for the formed palladium clusters is similar to that of the bulk palladium foil. Although a contraction of metal–metal distances can be expected for palladium nanoparticles, this result is in agreement with our previous studies of supported Pd particles with sizes from 1 to 10 nm on various supports. − The elongation of Pd–Pd distances can be caused by the presence of H or C atoms easily forming palladium hydrides , and carbides − and expanding the lattice. A similar explanation was presented by Ciapina and co-workers who concluded that H or C atoms can originate from catalytic decomposition of the organic compounds present during the synthesis …”

The structure of Pd-functionalized UiO-67 during CO2 hydrogenation

“…2.77 Å which is considerably higher than R Pd-Pd = 2.74 Å expected for metallic palladium, and exceeds the thermal expansion of Pd NPs. 49 This indicates that apart from palladium hydride, which is known to form reversibly, irreversible formation of an additional phase occurs. For smaller particles formed after activation in the reaction mixture, shorter R Pd-Pd values were observed under reaction conditions.…”

Deep Reinforcement Learning Environment Approach Based on Nanocatalyst XAS Diagnostics Graphic Formalization

“…The implementation of RL agents for the experimental design optimization and control can drastically facilitate material diagnostics, leveraging a compromise between exploration and the exploitation of the experiment's parameter space, especially in the case of the in situ and operando regimes. By taking into account the XAS diagnostics of palladiumbased nanocatalysts in these regimes, it was shown in several works [39,76] that both the reversible and the irreversible simultaneous formation of multiple impurity phases can occur under reaction conditions. The same can also be said about the other systems [77,78].…”

“…As knowing the features of the material's structure provides valuable insight into its structure-property relationships, XAS is a valuable tool for the study and fine-tuning of various materials, especially catalysts [29,36]. These materials dramatically speed up the chemical reactions they are involved in, providing an alternative reaction pathway with lower activation energy and thereby drastically facilitating reaction yield and selectivity [26,[36][37][38][39]; the vast majority of industrial chemical processes utilize catalysts [40].…”

“…Consequently, in situ XAS is often used to characterize the catalyst's structural evolution and the local environment of the active sites during both the heterogeneous form, where the catalyst is present in a different phase to that of the reactants, usually as a solid catalyst in a gas or liquid reaction mixture, and the homogenous version, which, in turn, involves a catalyst in the same phase as the substrate, most commonly a transition metal complex in a liquid solution [40]. The great advantage of XAS over other techniques such as X-ray diffraction (XRD) is that XAS is an element-specific technique [28,29], which can be used in operando and in situ regimes [38,43,44], and it is sensitive to both the surface and bulk [39,44,45] of the studied catalyst.…”