LAUSR

CO2 conversion to chemical fuels through photoreduction, electroreduction or thermoreduction is considered as one of the most effective methods to solve environmental pollution and energy shortage problems. However, recent studies show that the involved catalysts may undergo continuous reconstruction under realistic working conditions, which unfortunately causes controversial results concerning the active sites and reaction mechanism of CO2 reduction. Thus, it is necessary while challenging to real-time monitor the dynamic evolution of the catalysts and reaction intermediates by in situ techniques under experimental conditions. In this perspective, we start with the working principle and detection modes of various in situ characterization techniques. Subsequently, we systematically summarize the recent developments of in situ studies on probing the catalyst evolution during the CO2 reduction process. Further, we also focus on the progress of in situ studies on monitoring the reaction intermediates and catalytic products, in which we also highlight how the theoretical calculations are combined to reveal the reaction mechanism in detail. Finally, based on the representative study achievements, we have made some prospects and suggestions for in situ studies of CO2 reduction in the future.