Advanced Materials, volume 34, issue 19, pages 2109426
Structure‐Tailored Surface Oxide on Cu–Ga Intermetallics Enhances CO 2 Reduction Selectivity to Methanol at Ultralow Potential
Debabrata Bagchi
1, 2
,
Jithu Raj
1, 2
,
Ashutosh Kumar Singh
2, 3
,
Arjun Cherevotan
1, 2
,
Soumyabrata Roy
1, 2
,
Kaja Sai Manoj
1, 2
,
C.P Vinod
4
,
Sebastian Peter
1, 2
Publication type: Journal Article
Publication date: 2022-04-07
Journal:
Advanced Materials
scimago Q1
SJR: 9.191
CiteScore: 43.0
Impact factor: 27.4
ISSN: 09359648, 15214095
General Materials Science
Mechanical Engineering
Mechanics of Materials
Abstract
Electrochemical CO2 reduction reaction (eCO2 RR) is performed on two intermetallic compounds formed by copper and gallium metals (CuGa2 and Cu9 Ga4 ). Among them, CuGa2 selectively converts CO2 to methanol with remarkable Faradaic efficiency of 77.26% at an extremely low potential of -0.3 V vs RHE. The high performance of CuGa2 compared to Cu9 Ga4 is driven by its unique 2D structure, which retains surface and subsurface oxide species (Ga2 O3 ) even in the reduction atmosphere. The Ga2 O3 species is mapped by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) techniques and electrochemical measurements. The eCO2 RR selectivity to methanol are decreased at higher potential due to the lattice expansion caused by the reduction of the Ga2 O3 , which is probed by in situ XAFS, quasi in situ powder X-ray diffraction, and ex situ XPS measurements. The mechanism of the formation of methanol is visualized by in situ infrared (IR) spectroscopy and the source of the carbon of methanol at the molecular level is confirmed from the isotope-labeling experiments in presence of 13 CO2 . Finally, to minimize the mass transport limitations and improve the overall eCO2 RR performance, a poly(tetrafluoroethylene)-based gas diffusion electrode is used in the flow cell configuration.
Found
Are you a researcher?
Create a profile to get free access to personal recommendations for colleagues and new articles.