Controlled synthesis of Bi- and tri-nuclear Cu-oxo nanoclusters on metal-organic frameworks and the structure-reactivity correlations.

Qi Xue,Yun-Liang Soo,Tsz Woon Benedict Lo,Shogo Kawaguchi,Tai-Sing Wu,Bolong Huang,Molly Mengjung Li,Shik Chi Edman Tsang,Bryan Kit Yue Ng,Kwok Yin Wong,Ho Wing Man

doi:10.1039/d1sc05495c

Abstract

Precisely tuning the nuclearity of supported metal nanoclusters is pivotal for designing more superior catalytic systems, but it remains practically challenging. By utilising the chemical and molecular specificity of UiO-66-NH2 (a Zr-based metal–organic framework), we report the controlled synthesis of supported bi- and trinuclear Cu-oxo nanoclusters on the Zr6O4 nodal centres of UiO-66-NH2. We revealed the interplay between the surface structures of the active sites, adsorption configurations, catalytic reactivities and associated reaction energetics of structurally related Cu-based ‘single atoms’ and bi- and trinuclear species over our model photocatalytic formic acid reforming reaction. This work will offer practical insight that fills the critical knowledge gap in the design and engineering of new-generation atomic and nanocluster catalysts. The precise control of the structure and surface sensitivities is important as it can effectively lead to more reactive and selective catalytic systems. The supported bi- and trinuclear Cu-oxo nanoclusters exhibit notably different catalytic properties compared with the mononuclear ‘Cu1’ analogue, which provides critical insight for the engineering of more superior catalytic systems.

Highlights

With the global economic boom and population growth, energy conversion has become one of the most important issues in modern society, which o en requires the use of catalytic materials
We report the controlled synthesis of precise bi- and trinuclear Cu-oxo (Cu2- and Cu3-) active centres stabilised by the Zr6O4 nodes of UiO-66-NH2 (a Zr-based metal–organic framework (MOF)) by exploiting the underlying principles of coordination chemistry and solid-state chemistry
We have presented the controlled synthesis of Cuoxo nanoclusters on UiO-66-NH2, where the nuclearity of Cu sites can be nely adjusted, by exploiting the underlying principles of coordination chemistry and solid-state chemistry

Summary

Introduction

With the global economic boom and population growth, energy conversion has become one of the most important issues in modern society, which o en requires the use of catalytic materials. This can be attributed to the alternation of the electronic structure through ligand-to-metal charge transfer of the linker by direct interactions with extra-framework Cu-based species, such as Cu anchoring on the Zr6O4 nodal centre.[30] a d–d transition of CuII at 13 600 cmÀ1 can be observed from the calcined samples (1CuO, 2CuO, and 3CuO).

Results

Conclusion