Charge transfer between metal sites and supports is crucial for catalysis. Redox-inert supports are usually unfavorable due to their less electronic interaction with metal sites, which, we demonstrate, is not always correct. Herein, three metal-organic frameworks (MOFs) are chosen to mimic inert or active supports for Pt nanoparticles (NPs) and the photocatalysis is studied. Results demonstrate the formation of a Schottky junction between Pt and the MOFs, leading to the electron-donation effect of the MOFs. Under light irradiation, both the MOF electron-donation effect and Pt interband excitation dominate the Pt electron density. Compared with the "active" UiO-66 and MIL-125 supports, Pt NPs on the "inert" ZIF-8 exhibit higher electron density due to the higher Schottky barrier, resulting in superior photocatalytic activity. This work optimizes metal catalysts with non-reducible supports, and promotes the understanding of the relationship between the metal-support interaction and photocatalysis.

The exposed facets of supported catalysts play a crucial role in catalysis; however, they are usually ignored and related studies remain rare. Herein, we have fabricated a series of sandwich‐structured metal–organic framework composites, denoted ZIF‐8X@Pd@ZIF‐8 (x represents the morphology of ZIF‐8 core, i.e., ZIF‐8C exposing (100) facet, ZIF‐8RD exposing (110) facet, and ZIF‐8TRD exposing mixed (100) and (110) facets), featuring Pd nanoparticles deposited on the specific crystal facets of ZIF‐8 core, for hydrogenation of p‐chloronitrobenzene. The Pd electronic state is tailored by the ZIF‐8 core, where more electron‐deficient Pd is found in ZIF‐8C@Pd@ZIF‐8 than that in ZIF‐8RD@Pd@ZIF‐8, leading to discriminative adsorption of the −NO2 and −Cl groups of p‐chloronitrobenzene. Consequently, ZIF‐8C@Pd@ZIF‐8 exhibits excellent activity (97.6 %) and selectivity (98.1 %) to p‐chloroaniline. This work highlights crystal facet engineering of supports to modulate the microenvironment and electronic state of supported metal nanoparticles, offering a promising avenue to enhanced catalysis.

Charge transfer between metal sites and supports is crucial for catalysis. Redox-inert supports are usually unfavorable due to their less electronic interaction with metal sites, which, we demonstrate, is not always correct. Herein, three metal-organic frameworks (MOFs) are chosen to mimic inert or active supports for Pt nanoparticles (NPs) and the photocatalysis is studied. Results demonstrate the formation of a Schottky junction between Pt and the MOFs, leading to the electron-donation effect of the MOFs. Under light irradiation, both the MOF electron-donation effect and Pt interband excitation dominate the Pt electron density. Compared with the "active" UiO-66 and MIL-125 supports, Pt NPs on the "inert" ZIF-8 exhibit higher electron density due to the higher Schottky barrier, resulting in superior photocatalytic activity. This work optimizes metal catalysts with non-reducible supports, and promotes the understanding of the relationship between the metal-support interaction and photocatalysis.

Palladium-catalyzed C-C coupling reactions are of significant importance, but they often require harsh conditions. Herein, we report an interface-regulated photocatalytic Suzuki coupling reaction over Pd nanoparticles supported on a metal-organic framework (MOF), ZIF-8. Two Pd/MOFs were synthesized, Pd_PVP/ZIF-8 and Pd/ZIF-8, which have similar Pd sizes and loading amounts, except that the former contains poly(vinylpyrrolidone) (PVP) as a surfactant,. The diffuse-reflectance infrared Fourier transform of CO adsorption (CO-DRIFT) indicates that Pd/ZIF-8 represents a more negative electronic state of Pd than Pd_PVP/ZIF-8. In the photocatalytic Suzuki coupling reaction between iodobenzene and phenylboronic acid, Pd/ZIF-8 exhibits excellent performance (99.1% yield), much better than that of Pd_PVP/ZIF-8 (57.9% yield). Moreover, Pd/ZIF-8 is highly stable and shows broad substrate scope for this reaction. The superior activity of Pd/ZIF-8 can be attributed to sufficient electron transfer between the MOFs and Pd nanoparticles in the absence of an interfacial surfactant. This work provides new insights into a Pd-catalyzed C-C coupling reaction involving photocatalysis and interfacial electron transfer.

The exposed facets of supported catalysts play a crucial role in catalysis; however, they are usually ignored and related studies remain rare. Herein, we have fabricated a series of sandwich-structured metalorganic framework composites, denoted ZIF-8 X @Pd@ZIF-8 (x represents the morphology of ZIF-8 core, i.e., ZIF-8 C exposing (100) facet, ZIF-8 RD exposing (110) facet, and ZIF-8 TRD exposing mixed ( 100) and (110) facets), featuring Pd nanoparticles deposited on the specific crystal facets of ZIF-8 core, for hydrogenation of p-chloronitrobenzene.