Oxide inverse opals (IOs) with their high surface area and open porosity are promising candidates for catalyst support applications. Supports with confined mesoporous domains are of added value to heterogeneous catalysis. However, the fabrication of IOs with mesoporous or sub-macroporous voids (<100 nm) continues to be a challenge, and the diffusion of tracers in quasi-mesoporous IOs is yet to be adequately studied. In order to address these two problems, we synthesized ZnO IOs films with tunable pore sizes using chemical bath deposition and template-based approach. By decreasing the size of polystyrene (PS) template particles towards the mesoporous range, ZnO IOs with 50 nm-sized pores and open porosity were synthesized. The effect of the template-removal method on the pore geometry (spherical vs. gyroidal) was studied. The infiltration depth in the template was determined, and the factors influencing infiltration were assessed. The crystallinity and photonic stop-band of the IOs were studied using X-Ray diffraction and UV-Vis, respectively. The infiltration of tracer molecules (Alexa Fluor 488) in multilayered quasi-mesoporous ZnO IOs was confirmed via confocal laser scanning microscopy, while fluorescence correlation spectroscopy analysis revealed two distinct diffusion times in IOs assigned to diffusion through the pores (fast) and adsorption on the pore walls (slow).

The application of ZnO materials as solid‐state supports for molecular heterogeneous catalysis is contingent on the functionalization of the ZnO surface with stable self‐assembled monolayers (SAMs) of catalyst linker molecules. Herein, experimental and theoretical methods are used to study SAMs of azide‐terminated molecular catalyst linkers with two different anchor groups (silane and thiol) on poly and monocrystalline (0001, ) ZnO surfaces. Angle‐resolved and temperature‐dependent X‐ray photoelectron spectroscopy (XPS) is used to study SAM binding modes, thermal stabilities, and coverages. The binding strengths and atomistic ordering of the SAMs are determined via atom‐probe tomography (APT). Density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations provide insights on the influence of the ZnO surface polarity on the interaction affinity and conformational behavior of the SAMs. The investigations show that SAMs based on 3‐azidopropyltriethoxysilane possess a higher binding strength and thermal stability than the corresponding thiol. SAM surface coverage is strongly influenced by the surface polarity of ZnO, and the highest coverage is observed on the polycrystalline surface. To demonstrate the applicability of linker‐modified polycrystalline ZnO as a catalyst support, a chiral Rh diene complex is immobilized on the azide‐terminal of the SAM and its coverage is evaluated via XPS.