Impact of catalyst reuse on hydrogen production from agricultural waste electrolysis: An experimental investigation

Hydrogen production from agricultural waste via biomass electrolysis remains underexplored. Progress toward continuous-flow operation is needed, particularly because catalyst reuse is a major challenge affecting economic viability. This research studies two primary agricultural wastes (Spent Mushroom Compost, SMC, and Poultry Litter, PL) as feedstock for hydrogen generation using an H-type proton exchange membrane electrolysis cell (H-PEMEC). The work focuses on phosphomolybdic acid (PMo 12 ) as a catalyst and redox mediator without additional filtration or separation, requiring only the addition of new feedstock every cycle. In the first cycle, SMC and PL produced 27.5 mL and 22.7 mL of hydrogen per 0.5 g of feedstock, respectively, with SMC showing a 28.9% higher conversion efficiency (defined as H 2 produced with respect to H 2 present in the feedstock). Both feedstocks achieved 54-60% reductions in electrical energy consumption per kg of H 2 produced compared to water electrolysis. The reusability of PMo 12 was further evaluated using SMC. Without replacing the proton exchange membrane or the cathodic solution (H 3 PO 4 ), PMo 12 enabled 54.2 mL H 2 per 0.5 g of feedstock in the 15th cycle, demonstrating that maintaining the same catalyst amount across cycles enhances its effectiveness as both a redox mediator and charge carrier. These results indicate that continuous operation requires less catalyst than batch processing while achieving higher hydrogen yields. • Hydrogen generation via electrolysis of agricultural waste was investigated. • The recyclability of PMo 12 and its effects on conversion efficiency were explored. • SMC and PL registered H 2 production 27.5 mL and 22.7 mL per 0.5 g. • SMC achieved an H 2 conversion efficiency of 28.9%. • PMo 12 recycling enhanced the production of H 2 from 27.5 to 54.2 mL.