Selective conversion of CO₂ into value-added oxygenates, particularly methanol and dimethyl ether (DME), presents a promising route for CO₂ utilization. However, achieving both high selectivity and catalyst stability remained significant challenges. To address this, we report the fabrication of a core-shell-structured catalyst prepared by a steam-assisted crystallization (SAC) approach, in which highly dispersed Cu-ZnO nanoparticles (2.0–3.5 nm) are encapsulated within nanocrystalline silicalite-1 zeolite. The spatial confinement effects from silicalite-1 frameworks induce strong metal-zeolite interactions, effectively suppressing Cu-ZnO nanoparticle aggregation and sintering phenomena. This structural feature helps to preserve dominant populations of active Cu⁺ species on thermally stabilized Cu-ZnO nanoparticles. As a result, the optimized catalyst enables efficient tandem conversion of CO₂ to oxygenates, achieving a CO₂ conversion of 21.5% with an oxygenate selectivity of 83.0% toward dimethyl ether (DME, 72.5%) and methanol (10.5%), where an optimized catalyst exhibits exceptional catalytic performance for the tandem CO₂ -to-DME reaction. Comprehensive characterization reveals that the spatial confinement within the protective silicalite-1 matrix not only stabilizes highly dispersed Cu-ZnO nanoparticles and Cu⁺ sites but also facilitates the formation and stabilization of key reaction intermediates. These synergistic effects are directly responsible for an enhanced catalytic activity, high DME selectivity, and prolonged operational durability observed during 300 h of continuous CO₂ hydrogenation.

Carbonylation of dimethyl ether (DME) to methyl acetate (MA) is one of the key reactions for converting syngas into valuable chemicals and renewable energy sources. The reaction is predominantly catalyzed at Brønsted acid sites (BASs) on the 8-membered ring (8-MR) of the zeolite, which stabilizes the transient compound [Z–CH₃–CO]‡ of the rate-determining step (RDS). Although many studies focus on local descriptors, such as the RDS activation energy and enthalpy or BAS site geometry, these models often fail to fully describe the complex interplay among BAS distribution, pore connectivity, and the three-dimensional frameworks. To develop a more globalized approach for clarifying the structure-reactivity correlation, we synthesized various 8-MR-possessing zeolites, including CHA, FER, LTA, ERI, AEI, and STI with different Si/Al ratios and evaluated their activity (normalized per acid site) in the DME carbonylation reaction. PXRD, SEM(EDS), and BET characterization confirmed the successful synthesis of each zeolite, and NH₃-TPD and pyridine-IR analyses quantified their acid properties. Density functional theory (DFT) calculations show that the activation barrier of the RDS and the stability of the most abundant surface intermediate vary depending on the zeolite topology and active site environment. In this work, it was confirmed that “pocket-like” structures connecting two 8-MRs consecutively, which make 8-MR channels, have the most influential effect on catalytic behavior. Moreover, an adsorption isovolume-based descriptor, namely D_F, which captures the 3-dimensional distribution of BAS and the accessible reaction space, is introduced based on thorough geometry analyses and correlates specifically with the transition state stabilization in the RDS. It is noteworthy that MOR and FER exhibited the highest turnover frequency, correlated with their unique BAS arrangement and favorable channel geometry for transition state stabilization, as predicted by the isovolume-based descriptor proposed in this work. Consequently, extracting 3-dimensional structural descriptors that correlate with the RDS is essential for accurate prediction of structure–reactivity relationships. This contribution provides an effective design principle for untested zeolite topologies and may guide the rational design of advanced catalysts for DME carbonylation and related shape-selective processes.