Hydrogen gas (H2) is the primary storable fuel for pollution‐free energy production, with over 90 million tonnes used globally per year. More than 95% of H2is synthesized through metal‐catalyzed steam methane reforming that produces 11 tonnes of carbon dioxide (CO2) per tonne H2. “Green H2” from water electrolysis using renewable energy evolves no CO2, but costs 2–3× more, making it presently economically unviable. Here catalyst‐free conversion of waste plastic into clean H2along with high purity graphene is reported. The scalable procedure evolves no CO2when deconstructing polyolefins and produces H2in purities up to 94% at high mass yields. The sale of graphene byproduct at just 5% of its current value yields H2production at a negative cost. Life‐cycle assessment demonstrates a 39–84% reduction in emissions compared to other H2production methods, suggesting the flash H2process to be an economically viable, clean H2production route.
Current thermochemical methods to generate H2include gasification and steam reforming of coal and natural gas, in which anthropogenic CO2emission is inevitable. If biomass is used as a source of H2, the process can be considered carbon-neutral. Seaweeds are among the less studied types of biomass with great potential because they do not require freshwater. Unfortunately, reaction pathways to thermochemically convert salty and wet biomass into H2are limited. In this study, a catalytic alkaline thermal treatment of brown seaweed is investigated to produce high purity H2with substantially suppressed CO2formation making the overall biomass conversion not only carbon-neutral but also potentially carbon-negative. High-purity 69.69 mmol-H2/(dry-ash-free)g-brown seaweed is produced with a conversion as high as 71%. The hydroxide is involved in both H2production and in situ CO2capture, while the Ni/ZrO2catalyst enhanced the secondary H2formation via steam methane reforming and water-gas shift reactions.
more » « less- NSF-PAR ID:
- 10176829
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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