Observation of oxygen intermediates is the key to reveal the factors that limit the OER activity thus design of better catalysts. However, the liquid reaction environment makes it very challenging to probe oxygen intermediates at operating conditions. Although several in situ techniques are reported for the detection of intermediates on some catalysts, these methods apply only to certain circumstances. Therefore, so far, the most knowledge of oxygen intermediates is derived from theoretical simulations.

Herein, we developed a general and feasible method to probe oxygen intermediates. By employing alcohols as probing reagents, the oxygen intermediates can be readily captured. The method is so general and feasible that it can be adopted by every electrochemical laboratory. Besides the guidance for catalyst design, the chemical nature oxygen intermediates revealed from this work also open new opportunities for applying OER electrodes in other reactions.