Although electrochemical CO 2 reduction is one of the most promising ways to convert atmospheric CO 2 into value-added chemicals, there are still numerous limitations to overcome to achieve highly efficient CO 2 conversion performance. Herein, we report for the first time the development and use of a three-dimensional iron porphyrin-based graphene hydrogel (FePGH) as an electrocatalyst for extremely efficient robust CO 2 reduction to CO. Electrocatalytic CO 2 conversion was performed in aqueous medium with FePGH, which has a highly porous and conductive 3D graphene structure, resulting in high catalytic activity for CO production with ∼96.2% faradaic efficiency at a very low overpotential of 280 mV. Furthermore, FePGH showed considerable catalytic durability maintaining a consistent CO yield (96.4% FE) over 20 h electrolysis at the same overpotential, corresponding to the highest cathodic energy efficiency yet observed of 79.7% compared to other state-of-the-art immobilised metal complex electrocatalysts. This approach to fabricating a 3D graphene-based hydrogel electrocatalyst should provide an exciting new avenue for the development of other kinds of molecular electrocatalysts.
Bibliographical noteFunding Information:
This work was supported by the ARC Centre of Excellence Scheme (Project Number CE 140100012). JC also thanks the University of Wollongong (UOW) for a University Postgraduate Award. DRM is grateful for support from the Australian Research Council for his Australian Laureate Fellowship (Grant Number FL120100019). The authors thank Dr Patricia Hayes for assistance with Raman spectroscopy, and the Materials Node of the Australian National Fabrication Facility (ANFF) and the UOW Electron Microscopy Centre for their facilities and research support.
© 2019 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering