UiO-66, a Zr-based metal–organic framework (MOF), provides an ordered porous environment capable of adsorbing/retaining CO2 and oxygenated intermediates relevant for methanol synthesis. Although UiO-66-based composites containing Cu and Cu-Zn species show promising performance for CO2-to-methanol conversion, the role of the MOF framework in stabilizing the active metallic species under working conditions remains insufficiently understood. Here, the stabilization of copper species by UiO-66 and the influence of Zn promotion on Cu speciation and catalytic performance during CO2 hydrogenation are investigated. Operando X-ray absorption spectroscopy at the Cu, Zn, and Zr K-edges is combined with electron microscopy and density functional theory calculations to follow the evolution of metal species and the framework during reduction, reaction, and transient switching experiments. Zn promotes the formation and stability of highly dispersed Cu under reaction conditions, while the Zr6 nodes of UiO-66 respond dynamically through reversible hydroxylation and dehydroxylation. By correlating metal speciation, framework response, and methanol productivity under continuous-flow conditions, this work provides molecular-level insight into metal stabilization in Zr-based MOFs and informs the design of MOF-based catalysts for CO2 hydrogenation. ... Read more

Understanding how surface species evolve under reaction conditions is essential for improving catalyst design for efficient CO2 hydrogenation. This work combines systematic DFT calculations with grand canonical sampling to investigate the stability and reactivity of Ga–H species on β-Ga2O3 across a range of reaction conditions. Initial DFT studies reveal that when Ga–H species are present, they facilitate formate formation via a low-barrier pathway, largely independent of the surface termination or hydrogen site. However, grand canonical sampling shows that under a broad range of reaction conditions─especially at high oxygen chemical potentials associated with high water content─Ga–H species are thermodynamically inaccessible. Furthermore, adsorbed water molecules can block reactive sites, inhibiting CO2 activation even when hydrides are present. These findings suggest that the lack of accessible hydride species, rather than their intrinsic reactivity, could contribute to reduced catalytic performance of β-Ga2O3 under more oxidizing, high-conversion conditions. ... Read more

Data-driven catalyst design is a promising approach for addressing the challenges in identifying suitable catalysts for synthetic transformations. Models with descriptor calculations relying solely on the precatalyst structure are potentially generalizable but may overlook catalyst-substrate interactions. This study explores substrate-specific interactions in the context of Rh-catalyzed asymmetric hydrogenation to elucidate the impact of substrate inclusion on the catalyst structure and on the descriptors derived from it. We compare a catalyst-substrate complex with methyl 2-acetamidoacrylate as a model substrate with the generic precatalyst structure involving a placeholder substrate, norbornadiene, across 11 Rh-based catalysts with bidentate bisphosphine ligands. For these systems, a full conformer ensemble analysis reveals an intriguing finding: the rigid substrate induces conformational freedom in the ligand. This flexibility gives rise to a more diverse conformer landscape, showing a previously overlooked aspect of catalyst-substrate dynamics. Electronic descriptor variations particularly highlight differences between substrate-specific and precatalyst structures. This study suggests that generic precatalyst-like models may lack crucial insights into the conformational freedom of the catalyst. We speculate that such conformational freedom may be a more general phenomenon that can influence the development of generalizable predictive models of computational TM-based catalysis. ... Read more