We investigated the charge transfer between Au25(SG)18 nanoclusters and metal–organic framework (MOF) supports including Mil-101-Cr, Mil-125-Ti, and ZIF-8 by an X-ray photoemission technique and discussed the influence of resulted charge states of supported Au25(SG)18 nanoclusters on the 4-nitrophenol reduction reaction. Charge transfer from Au25(SG)18 to Mil-101-Cr induces positive charge Auδ+ (0 < δ < 1) while charge transfer from ZIF-8 to Au25(SG)18 generates negative charge Auδ− due to different metal–support interactions. Au25(SG)18 on Mil-125 shows metallic Au0, similar to unsupported Au25(SG)18, due to negligible charge transfer. The resulted charge state of Auδ− inhibits the formation of adsorbed hydride (H–) species because of electrostatic repulsion, while Auδ+ impairs the reductive ability of adsorbed hydride (H–) species due to strong affinity between them. In comparison, metallic Au0 in Au25(SG)18/Mil-125 and unsupported Au25(SG)18 presents the optimum catalytic activity. The current work provides guidelines to design effective metal nanoclusters in heterogeneous catalysis through metal–support interaction exerted by metal-oxo/nitric clusters within MOFs.

Artificial light-driven splitting of water into hydrogen involves multiple links to emulate natural photosynthesis, including light absorption, electron or energy transfer, surface catalysis et al., in which, the mass transportation of sacrificial reagent and reactant is always ignored. Metal-organic cage (MOC) of Pd 6 Ru 8 (MOC-16), assembling multiple photosensitive Ru and catalytic Pd concomitant with directional electron transfer between them, provides an opportunity to explore the environmental effects from the view point of mass transportation without disturbance of other links. Zr-MOF of UiO-66 is used as a matrix to heterogenize MOC-16 and a series of characterizations are carried out to unravel the composition, structure and optical properties. The intact MOC-16 remains with long-term photo-stability and the outstanding photocatalytic activity is obtained by virtue of a long-lived triplet state. Three matrixes of ZIF-8, ZIF-8 derived carbonate CZIF, and UiO-66 are intercompared for mass transfer based on wettability and porous structure. Water molecule directly takes part in the formation of H 2 catalyzed by MOC-16@UiO-66, evidenced by a kinetic isotope effect, in addition to the proton delivery thanks to the hydrophilic nature of UiO-66. The porous structure of UiO-66 is essential for the permeation of sacrificial reagent to serve as twoelectron donor, in sharp contrast as one-electron donor in nonporous CZIF matrix. These results highlight the importance of microenviroment surrounding molecular catalysts in view of the heterogenization of molecular catalysts, meanwhile, providing a prominent guidance on how to choose 3D support to bridge the homogenous and heterogenous system.[a] D.

This review focuses on taking porous matrixes as ‘molecular containers’ to tune and regulate photophysical and photocatalytic properties of molecular photosensitizers and/or catalysts for application of solar energy conversion. The...

No abstract

Photocatalytic organic conversion is considered an efficient, environmentally friendly, and energy-saving strategy for organic synthesis. In recent decades, the molecular cage has emerged as a creative functional material with broad...