In Situ Spectroscopic Methods for Electrocatalytic CO2 Reduction

Lei Jin,Ali Seifitokaldani

doi:10.3390/catal10050481

Abstract

Electrochemical reduction of CO2 to value-added chemicals and fuels is a promising approach to store renewable energy while closing the anthropogenic carbon cycle. Despite significant advances in developing new electrocatalysts, this system still lacks enough energy conversion efficiency to become a viable technology for industrial applications. To develop an active and selective electrocatalyst and engineer the reaction environment to achieve high energy conversion efficiency, we need to improve our knowledge of the reaction mechanism and material structure under reaction conditions. In situ spectroscopies are among the most powerful tools which enable measurements of the system under real conditions. These methods provide information about reaction intermediates and possible reaction pathways, electrocatalyst structure and active sites, as well as the effect of the reaction environment on products distribution. This review aims to highlight the utilization of in situ spectroscopic methods that enhance our understanding of the CO2 reduction reaction. Infrared, Raman, X-ray absorption, X-ray photoelectron, and mass spectroscopies are discussed here. The critical challenges associated with current state-of-the-art systems are identified and insights on emerging prospects are discussed.

Highlights

The increasing concentration of atmospheric carbon dioxide (CO2 ) is believed to contribute to the anthropogenic climate change [1,2]
Unlike water splitting where H2 and O2 are single products in cathode and anode of the electrochemical cell, the process of CO2 reduction reaction (CO2 RR) is more complicated because different possible reaction intermediates/products are formed by multiple protons (H+ ) /electrons (e– )
In other work, using in situ X-ray absorption spectroscopy (XAS), Sargent’s group demonstrated the preferential exposure of highly active Bi (110) facets on BiOBr− electrocatalyst caused achieving a high selectivity toward formate over 90% [110]

Summary

Introduction

The increasing concentration of atmospheric carbon dioxide (CO2 ) is believed to contribute to the anthropogenic climate change [1,2]. Electrochemical activation or exposure of samples to air during chamber-to-chamber transportation, introduces contamination and undesired surface functional groups to the surface of the electrocatalyst, thereby disturbing the interpretation of spectroscopic fingerprints To overcome these shortcomings and accurately picture the physical and Catalysts 2020, 10, 481 chemical processes, and to further develop efficient electrocatalysts for CO2RR with high performance and durability, we need to take advantage of additional characterization tools. To overcome these shortcomings and accurately picture the physical and chemical processes, and to further develop efficient electrocatalysts for CO2 RR with high performance and durability, we need to take advantage of additional characterization tools. CO2 RR are discussed to provide fresh insights into the development of CO2 RR

In Situ Spectroscopic Techniques

Schematic

Summary and Outlook

Findings

Limitation