Optimising polyoxometalate catalysed hydrogen generation from poultry litter-biomass electrolysis through response surface methodology

Electrolysis from biomass offers a viable approach to transforming organic waste into high-purity hydrogen that remains unexplored. The study discusses optimising the pre-treatment conditions to maximise hydrogen production from poultry litter via electrolysis. Biomass electrolysis involves two steps: first, the biomass material is broken down, and then the hydrogen produced during the electrolysis process is used. The first step is vital because it significantly impacts the efficiency and effectiveness of the entire operation, accounting for around 80 % of the overall process performance. A central composite design (CCD) with response surface methodology (RSM) was used for optimisation, considering several operational parameters, including the temperature, catalyst concentration, pre-treatment duration, and biomass concentration. A modified version of the H-type proton-exchange membrane (PEM) electrolytic cell with a reduced electrode distance was used for the experiments. Phosphomolybdic acid (POM) was used as a catalyst and charge carrier to speed up the breakdown of poultry litter. The optimised pre-treatment conditions that resulted in a maximum hydrogen yield of 24.3 mL after 4 h of electrolysis were found to be: poultry litter concentration of 19.16 g/L, pre-treatment temperature of 101.25 °C, catalyst concentration of 0.197 mol/L, and pre-treatment duration of 3 h.