Integrated low carbon H2 conversion with in situ carbon mineralization from aqueous biomass oxygenate precursors by tuning reactive multiphase chemical interactions

Abstract

Meeting our rising demand for clean energy carriers such as H₂ from renewable biomass resources is challenged by the co-emission of CO₂ and CH₄. To address this challenge, we design novel reactive separation pathways that integrate multiphase chemical reactions by harnessing Ca and Mg bearing minerals as a sorbent to capture CO₂ released during the hydrothermal deconstruction of aqueous biomass oxygenates to produce H₂ and solid carbonates via low temperature aqueous phase reforming and thermodynamically downhill carbon mineralization. Earth abundant catalysts such as Ni/Al₂O₃ are effective in producing H₂ yields as high as 79% and 74% using ethylene glycol and methanol in the presence of Ca(OH)₂ as an alkaline sorbent, without contaminating or deactivating the catalyst. H₂ yields with in situ carbon mineralization using a Ni or Pt/Al₂O₃ catalyst are enhanced based on the following order of reactivity: acetate < glycerol < methanol < formate < ethylene glycol. These studies demonstrate that the multiphase chemical interactions can be successfully tuned to enhance H₂ yields through the selective cleavage of C–C bonds using Ni/Al₂O₃ catalysts to deconstruct biomass oxygenates for producing H₂ and CO₂, and in situ carbon mineralization by harnessing abundant alkaline materials, as demonstrated using ladle slag. This approach unlocks new scientific possibilities for harnessing multiple emissions including abundant organic-rich wastewater streams and alkaline industrial residues to co-produce low carbon H₂ and carbonate-bearing materials for use in construction by using renewable solar thermal energy resources.