New experimental approaches for biomass assisted electrolysis of water for green hydrogen production

Abstract

The electrolysis of water assisted by biomass and boosted by hydrogen peroxide was explored in this work using graphene nanoplatelets supported by monometallic nickel and bimetallic Pt-Ni anodic catalysts in a half-electrochemical cell. The study investigated wheat straw hydrolysate as well as separately a glucose stream as an alternative oxidation reaction source to replace the more energy-intensive conventional OER in electrolysis of water. Additionally, impact of a green oxidizer (hydrogen peroxide) in small concentrations was also assessed for synergetic effects in improving the water electrolysis to generate green hydrogen. A three-electrode (half) electrochemical cell was used for all experiments with glassy carbon as a working electrode. The anodic catalysts were synthesized by modified polyol method and physico-chemically characterized. The wheat straw hydrolysate stream was used as an alternative oxidation source in an acidic media using a bimetallic Pt-Ni/GNPs anodic catalyst while Glucose was used as an alternative oxidation source in alkaline media using Ni/GNPs. CV and CA studies were performed to electrochemically assess the performance of all the experimental systems. Enhanced electrochemical activity was observed for both the biomass sources and the anodic catalysts in all the studied systems at lower onset potentials than the conventional water electrolysis. Similarly, adding hydrogen peroxide in very small concentrations (0.018-0.09M) was observed to enhance the overall activity of the biomass-assisted water electrolysis system indicating the potential of green oxidizers to remove the catalyst-poisoning species and improving the stability and performance of anodic catalysts. The study promises the role of abundantly available biomass-derived organic molecules as a less energy-intensive alternative oxidation source for green hydrogen production. It also demonstrates the synergetic potential of hydrogen peroxide to enhance water electrolysis using biomass assistance for green hydrogen potential and to circumvent the catalyst poisoning bottleneck as normally observed in using larger organic molecules as alternative oxidation species.