Decoupling the Interfacial Catalysis of CeO₂-Supported Rh Catalysts Tuned by CeO₂ Morphology and Rh Particle Size in CO₂ Hydrogenation

Abstract

Metal–oxide interfaces play a crucial role in catalyzing CO2 conversion, while comprehensively decoupling interfacial catalysis is challenging due to their structural complexity. Herein, Rh/CeO2 catalysts, whose interfacial structures are finely tuned by altering the CeO2 morphologies and Rh particle sizes, were employed for CO2 hydrogenation. The results reveal that the density of interfacial oxygen vacancies that varies with the CeO2 morphologies determines the catalytic activity, while the product selectivity strongly depends on the nature of supported Rh species. With a decrease in Rh particle size, the weakened metallicity results in the suppression of the Sabatier reaction and thus the low CH4 selectivity. Meanwhile, the enhanced reverse water–gas shift process that is more easily catalyzed than the Sabatier reaction contributes to the promotion of catalytic CO2 efficiency. Interestingly, the CH4 selectivity increases with the reaction temperature rise at fine Rh particles, which could be ascribed to the enhanced H-spillover effect at high temperatures. Spectroscopic results confirm CO2 hydrogenation proceeding through a redox mechanism to generate an adsorbed CO intermediate that either is further hydrogenated into CH4 with strong CO adsorption capacity/H-spillover effect or desorbs directly into CO.

Efficient Catalytic Hydroformylation of Alkenes on Rh/CeO2 Catalysts Modulated by CeO2 Morphology

“…EDX analysis also showed that the supported Rh was randomly dispersed on different planes of the CeO 2 support, and no preferential enrichment was observed. This further confirmed that Rh active sites were uniformly dispersed. , Thus, the CeO 2 morphology determined the properties of the Rh–CeO 2 interface in these catalysts.…”

“…CeO 2 rods (CeO 2 -R), polyhedra (CeO 2 -P), and octahedra (CeO 2 -O) with well-controlled morphologies were prepared following previously reported procedures . The IR spectra of these samples showed several obvious peaks at 400–800 cm –1 ascribed to the tensile vibration of the Ce–O bond (Figure S1).…”

Reinforcing the Efficiency of Photothermal Catalytic CO2 Methanation through Integration of Ru Nanoparticles with Photothermal MnCo2O4 Nanosheets

“…As demonstrated in Figure a, MnCo 2 O 4 exhibits two distinct peaks at 302 and 452 °C, which could be attributed to the reduction of CoO y and MnO y , as well as the strong interaction between Mn and Co. However, the TPR profile of Ru/MnCo 2 O 4 displays two broader and unsymmetrical peaks centered at 172 and 387 °C, appearing at lower temperatures than those observed for MnCo 2 O 4 due to efficient dissociation and spillover of H 2 . Additionally, CO 2 temperature-programmed desorption (CO 2 -TPD) measurements were employed to investigate CO 2 adsorption and desorption behavior (Figure b).…”

Pt Single Atoms and Nanosized Clusters as Catalytic Reaction Platforms for Selective Hydrogenation Applications

“…As particle size decreases, the catalytic behavior of nanosized cluster catalysts (NCCs) and single-atom catalysts (SACs) changes dramatically in different practical reaction processes. , Specifically, the particle size demonstrates a pivotal role in regulating the catalytic function of nanosized heterogeneous supported catalysts, and the size-influenced reactions can be attributed to their electronic/geometrical properties. , NCCs, consisting of certain aggregations of metal atoms, can show unanticipated catalytic properties due to various chemical properties, such as structural shell closings, superatom characters, and quantum confinements. , When metal atoms are reduced to single atoms (SACs), they maximize the number of interfacial atoms, allowing all metal atoms to be accessible to reactant molecules as atoms located at corners, edges, and surfaces disappear. ,, Importantly, NCCs/SACs with well-defined surface metal atomic arrangements provide applicable active sites and catalytic reaction platforms for selective hydrogenation of unsaturated aldehydes. ,, However, few studies have explored the relationship between surface atom structure and reaction selectivity in controlling catalytic conversion. This inspires us to investigate the crucial role of the surface atom structure in controlling selectivity in the hydrogenation of unsaturated aldehydes in order to provide guidance for the development of novel NCCs/SACs.…”