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.