Syngas/hydrogen production from self-supporting corncob sacrificial anode-assisted water electrolysis: Aspen Plus simulation and experimental study

Abstract

Carbon-assisted water electrolysis (CAEW), leveraging the carbon oxidation reaction (COR) in place of the oxygen evolution reaction (OER), substantially reduces the energy demand for H₂ production. However, CO₂ is the primary anode product in conventional CAEW, limiting its practical value. Additionally, mass transfer constraints significantly impact the efficiency of COR in substituting for OER in traditional CAEW systems. This study proposes an advanced CAEW process for syngas production, utilizing Aspen Plus simulations to generate H₂ at the cathode and CO at the anode. A self-supporting corncob biomass char sacrificial anode was synthesized via hydrothermal-molding-pyrolysis. Simulation outcomes demonstrate that energy consumption for syngas production decreases as the H₂/CO ratio increases within the 1 to 5 range, reaching minimum values of 1.14 kWh/m³-H₂ and 1.45 kWh/m³-syngas theoretically at an H₂/CO ratio of 3. Electrochemical testing reveals that the corncob biomass char anode operates at a potential approximately 1/3 lower than that of a Pt anode while maintaining cathodic H₂ production efficiency. The corncob sacrificial anode produces reduced gas and O₂, confirming the replacement of OER by COR. Additionally, the anode gas contains around 10 % CO, validating CAEW’s feasibility for syngas production.