A universal ligand mediated method for large scale synthesis of transition metal single atom catalysts

Hongzhou Yang,Lu Shang,Geoffrey I N Waterhouse,Tierui Zhang,Qinghua Zhang,Run Shi,Lin Gu

doi:10.1038/s41467-019-12510-0

Abstract

There is interest in metal single atom catalysts due to their remarkable activity and stability. However, the synthesis of metal single atom catalysts remains somewhat ad hoc, with no universal strategy yet reported that allows their generic synthesis. Herein, we report a universal synthetic strategy that allows the synthesis of transition metal single atom catalysts containing Cr, Mn, Fe, Co, Ni, Cu, Zn, Ru, Pt or combinations thereof. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and extended X-ray absorption fine structure spectroscopy confirm that the transition metal atoms are uniformly dispersed over a carbon black support. The introduced synthetic method allows the production of carbon-supported metal single atom catalysts in large quantities (>1 kg scale) with high metal loadings. A Ni single atom catalyst exhibits outstanding activity for electrochemical reduction of carbon dioxide to carbon monoxide, achieving a 98.9% Faradaic efficiency at −1.2 V.

Highlights

There is interest in metal single atom catalysts due to their remarkable activity and stability
The X-ray diffraction (XRD) patterns of all M-Single-atom catalysts (SACs) showed broad peaks centered around 24° and 44° (Fig. 2a), corresponding to the (002) and (100) planes of graphite
transmission electron microscopy (TEM) images for the M-SACs confirmed that no metal clusters or nanoparticles were present on the carbon black support (Fig. 2b and Supplementary Figs. 2–9)

Summary

Introduction

There is interest in metal single atom catalysts due to their remarkable activity and stability. The introduced synthetic method allows the production of carbon-supported metal single atom catalysts in large quantities (>1 kg scale) with high metal loadings. A single synthetic strategy that allows the large-scale synthesis of SACs containing almost any transition metal with high metal loadings has proven elusive. Such a synthetic strategy would expedite the utilization of SACs across the chemical sector. Aberrationcorrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy confirm that all M-SACs contain metals atomically dispersed in porphyrin-like MN4 sites over the carbon support (no cluster or nanoparticle formation is observed). The performance of the different M-SACs are subsequently evaluated for electrochemical CO2 reduction, with the Ni-SAC containing 2.5 wt.% demonstrating outstanding performance for CO2 reduction to CO (~99% Faradaic efficiency at −1.2 V)

Methods

Results

Conclusion