Optimization and scaling-up of porous solid electrolyte electrochemical reactors for hydrogen peroxide electrosynthesis

The recently developed porous solid electrolyte (PSE) reactor for electrosynthesis of hydrogen peroxide (H2O2) has attracted significant global interest. However, scaling up the PSE reactor for practical applications poses challenges, particularly due to performance decline in enlarged reactors. Here we systematically investigate how factors such as material selection, assembly parameters, flow field patterns, and operating conditions influence H2O2 electrosynthesis in the PSE reactor. Our findings reveal that the performance decline during reactor scale-up is primarily caused by the uneven flow field in the PSE layer. Based on these insights, we optimize the reactor design and develop a 12-unit modular electrode stack PSE reactor with a total electrode area of 1200 cm2. The scaled-up reactor maintains efficient H2O2 electrosynthesis without significant performance decline. It operates stably for over 400 h and can produce up to 2.5 kg pure H2O2 (~83 kg 3% H2O2 solutions) per day with considerably lower energy costs (0.2‒0.8 USD/kg H2O2) than the market prices of H2O2 stocks. This work represents a crucial advancement in the development of PSE reactor technology for practical H2O2 electrosynthesis.