Progress and Perspective for In Situ Studies of CO₂ Reduction

Abstract

CO 2 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 CO 2 reduction. Thus, it is necessary, while challenging, to monitor in real time 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 CO 2 reduction process. We further focus on the progress of in situ studies in 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 achievements in the representative studies, we present some prospects and suggestions for in situ studies of CO 2 reduction in the future.

Towards the Large-Scale Electrochemical Reduction of Carbon Dioxide

“…In addition to pre-and post-reaction characterization, in situ measurement have also been found useful in giving the real-time dynamic change of the catalyst surface morphology during CO2 electroreduction. Great achievements in acquiring morphological information of the catalyst surface have been the use of in situ XRD, EXAFS, and environment transmission electron microscopy (ETEM) [82]. For example, a study by Damsgaard et al utilizes in situ ETEM to follow the morphological evolution of the catalyst surface, GaPd2.…”

Oxygen Defects in Nanostructured Metal‐Oxide Gas Sensors: Recent Advances and Challenges†

“…Several in situ techniques have been developed, including in situ XPS, in situ UV‐vis, in situ EPR, and so on (Figure 4). [ 75‐76 ] The terms “ in situ ” and “ operando ” derive from the field of heterogeneous catalysis, in which “ in situ ” represents under conditions relevant for the gas sensor's operation (pressure, temperature, atmospheric composition), but does not involve a real‐time evaluation of the sensor performance of the probed specimen. “ Operando ” refers to performing under application‐ relevant conditions on real sensor devices and involves the real‐ time evaluation of the sensor performance of the probed specimen.…”

“…[ 70 ] (i) Schemes of in situ transmission electron microscopy. [ 75 ]…”

“…It is important to note that in situ TEM experiments have stringent requirements for both operating environment and sample preparation. [ 75,77 ] Ding et al . reported a rational method for tracking the oxygen vacancy diffusion of pure and Sm‐doped cerium dioxide (CeO 2 ) single crystals by in situ TEM.…”

Operando spectroscopy of nanoscopic metal/covalent organic framework electrocatalysts

“…To this end, operando spectroscopy, [24][25][26][27][28][29] that which is performed as the catalyst is functioning, is playing a substantial role in aiding researchers in their efforts to fully understand the function of electrocatalytic MOFs and COFs, and from this understanding, develop design rules towards the construction of next-generation systems. The primary spectroscopic techniques include, but are not limited to, UV-Vis absorption, Raman, infrared, and X-ray absorption spectroscopy (Fig.…”