Uncovering the structure evolution and real active species of energy catalytic materials under reaction conditions is important for both understanding structure-activity relationship and constructing electrocatalysts for CO electroreduction (COER). And integrating COER with an anodic organic transformation to replace the oxygen evolution reaction is highly desirable. Here, InO is selected as the model material to reveal the surface reconstruction under COER condition. In situ and ex situ results reveal that the electrochemical in situ reconstruction of crystalline InO leads to the formation of crystalline-In/amorphous-InO heterostructure (In/InO). In/InO acts as the real active phase with Faradaic efficiency of ~ 89.2% for the formate, outperforming In (~67.5%). The improved performance can be ascribed to electron-rich In rectified by Schottky effect of In/InO heterostructure. Impressively, formate and high-value octanenitrile can be simultaneously achieved by integrating COER with octylamine oxidation in an In/InO‖NiP two-electrode electrolyzer.