An Experimental Investigation of Hydrogen Production Through Biomass Electrolysis

This work investigated hydrogen production from biomass feedstocks (i.e., glucose, starch, lignin and cellulose) using a 100 mL h-type proton exchange membrane electrolysis cell. Biomass electrolysis is a promising process for hydrogen production, although low in technology readiness level, but with a series of recognised advantages: (i) lower-temperature conditions (compared to thermochemical processes), (ii) minimal energy consumption and low-cost post-production, (iii) potential to synthesise high-volume H ₂ and (iv) smaller carbon footprint compared to thermochemical processes. A Lewis acid (FeCl ₃) was employed as a charge carrier and redox medium to aid in the depolymerisation/oxidation of biomass components. A comprehensive analysis was conducted, measuring the H ₂ and CO ₂ emission volume and performing electrochemical analysis (i.e., linear sweep voltammetry and chronoamperometry) to better understand the process. For the first time, the influence of temperature on current density and H ₂ evolution was studied at temperatures ranging from ambient temperature (i.e., 19 °C) to 80 °C. The highest H ₂ volume was 12.1 mL, which was produced by FeCl ₃-mediated electrolysis of glucose at ambient temperature, which was up to two times higher than starch, lignin and cellulose at 1.20 V. Of the substrates examined, glucose also showed a maximum power-to-H ₂-yield ratio of 30.99 kWh/kg. The results showed that hydrogen can be produced from biomass feedstock at ambient temperature when a Lewis acid (FeCl ₃) is employed and with a higher yield rate and a lower electricity consumption compared to water electrolysis.