Seeing is believing: In-situ visualising dynamic evolution in CO2 electrolysis

CO2 reduction reaction (CO2RR), as a promising carbon neutral strategy, enables the production of valuable chemicals and fuels from greenhouse gas. Despite tremendous efforts in developing CO2RR catalysts to improve activity, selectivity and stability, mechanisms behind the catalytic performance, however, are still under-explored owing largely to limited characterisation capability. In this review, advances in in-situ imaging technologies for studying CO2RR have been overviewed. These technologies emerge as powerful tools to track the transformation of catalyst materials over real-time and space, under CO2RR operating conditions. The review discusses emerging opportunities in the direction of combined in-situ characterisation techniques and machine learning to aid further discovery of structure-function relationships in CO2RR.