Charge State of Au25(SG)18 Nanoclusters Induced by Interaction with a Metal Organic Framework Support and Its Effect on Catalytic Performance

Kunlin Chu; Yucheng Luo; Dongjun Wu; Zhifang Su; Jianying Shi; Jin Zhong Zhang; Cheng-Yong Su

doi:10.1021/acs.jpclett.1c02090

Charge State of Au₂₅(SG)₁₈ Nanoclusters Induced by Interaction with a Metal Organic Framework Support and Its Effect on Catalytic Performance

J Phys Chem Lett. 2021 Aug 26;12(33):8003-8008. doi: 10.1021/acs.jpclett.1c02090. Epub 2021 Aug 16.

Authors

Kunlin Chu¹, Yucheng Luo¹, Dongjun Wu¹, Zhifang Su¹, Jianying Shi¹, Jin Zhong Zhang², Cheng-Yong Su¹

Affiliations

¹ School of Chemistry, Sun Yat-sen University, Guangzhou 510275, P. R. China.
² Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, United States.

PMID: 34433276
DOI: 10.1021/acs.jpclett.1c02090

Abstract

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 Au^δ+ (0 < δ < 1) while charge transfer from ZIF-8 to Au₂₅(SG)₁₈ generates negative charge Au^δ- 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 Au^δ- inhibits the formation of adsorbed hydride (H^-) species because of electrostatic repulsion, while Au^δ+ 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.