Direct Visualization of Atomic Structure in Multivariate Metal-Organic Frameworks (MOFs) for Guiding Electrocatalysts Design

Dengrong Sun; Lok Wing Wong; Hok Yin Wong; Ka Hei Lai; Lin Ye; Xinyao Xv; Thuc Hue Ly; Qingming Deng; Jiong Zhao

doi:10.1002/anie.202216008

Direct Visualization of Atomic Structure in Multivariate Metal-Organic Frameworks (MOFs) for Guiding Electrocatalysts Design

Angew Chem Int Ed Engl. 2023 Jan 23;62(4):e202216008. doi: 10.1002/anie.202216008. Epub 2022 Dec 14.

Authors

Dengrong Sun^{1

2}, Lok Wing Wong¹, Hok Yin Wong¹, Ka Hei Lai¹, Lin Ye¹, Xinyao Xv³, Thuc Hue Ly⁴, Qingming Deng³, Jiong Zhao¹

Affiliations

¹ Department of Applied Physics, The Hong Kong Polytechnic University Hung Hom, Kowloon, Hong Kong, China.
² College of Architecture and Environment, National Engineering Research Centre for Flue Gas Desulfurization, Carbon Neutral Technology Innovation Center of Sichuan, Sichuan University, Chengdu, 610065, China.
³ Physics Department and Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, Huaiyin Normal University, Huaian, 223300, China.
⁴ Department of Chemistry and Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Kowloon, Hong Kong, China.

PMID: 36399056
DOI: 10.1002/anie.202216008

Abstract

The direct utilization of metal-organic frameworks (MOFs) for electrocatalytic oxygen evolution reaction (OER) has attracted increasing interests. Herein, we employ the low-dose integrated differential phase contrast-scanning transmission electron microscopy (iDPC-STEM) technique to visualize the atomic structure of multivariate MOFs (MTV-MOFs) for guiding the structural design of bulk MOFs for efficient OER. The iDPC-STEM images revealed that incorporating Fe³⁺ or 2-aminoterephthalate (ATA) into Ni-BDC (BDC: benzenedicarboxylate) can introduce inhomogeneous lattice strain that weaken the coordination bonds, which can be selectively cleaved via a mild heat treatment to simultaneously generate coordinatively unsaturated metal sites, conductive Ni@C and hierarchical porous structure. Thus, excellent OER activity with current densities of 10 and 100 mA cm^-2 are achieved over the defective MOFs at small overpotentials of 286 mV and 365 mV, respectively, which is superior to the commercial RuO₂ catalyst and most of the bulk MOFs.

Keywords: Defect Engineering; Metal-Organic Frameworks; Multivariate MOFs; Oxygen Evolution Reaction; iDPC-STEM.