Electrolysis of Aqueous Polymer and Biomass Solutions for Low-cost Production of Hydrogen and Valued-added Chemicals

Low-cost, low-temperature (LT) production of high-purity hydrogen (H2) is the bottleneck of contemporary hydrogen-based clean energy technologies. This study was to investigate hydrogen production and its energy efficiency via LT-electrolysis of polyethylene oxide (PEO) and lignin solutions. Comparative experimental studies were explored using a lab-scale proton-exchange membrane (PEM) electrolyzer: (a) PEO solutions (1.0 and 2.0% w/v) at operating temperatures of 29 and 32°C, and (b) lignin solutions at 25, 35, and 80°C. In electrolysis of PEO, H₂ production rates were 36.3, 19.7, and 31.3 ml/min at 29°C, and 52.3, 32.9, and 38.5 ml/min at 32°C for 1.0% PEO, 2.0% PEO, and distilled water, respectively. Energy savings of up to 26.50% were observed compared to pure water electrolysis, with the specific energy consumption ranging from 29.01 to 31.71 kWh.kg⁻¹. In the lignin experiments, H₂ production rates increased from 1 ml/min at 25°C to 40 ml/min at 80°C, while the specific energy consumption decreased from 255 kWh.kg⁻¹ to 5.5 kWh.kg⁻¹. FTIR was utilized to confirm the formation of new chemicals in electrolysis. The results demonstrate that both PEO and lignin solutions can enhance H₂ production and reduce energy consumption compared to traditional water electrolysis.