Thus, the spatiotemporal imaging approach developed in this work has shown to be able to universally visualize in real-time, as never seen before, the on-electrodes electrochemical processes in the electrolyte itself. Importantly, the applicability of this proposed approach was successfully evaluated for practically realizing the 'self-neutralization' phenomenon via decreasing the inter-electrodes distance, and also for understanding the enhancing effects of electrolyte's flow on the overall electrochemical water splitting reaction performance.