Enhanced H2 recovery by coupling the water–gas shift reaction with in situ CO2 capture and mineralization using earth abundant Ca- and Mg-silicates and hydroxides

Abstract

Decarbonization of clean energy carriers such as H₂ by coherent integration of multiphase chemical pathways with inherent carbon mineralization is a thermodynamically downhill pathway designed for a sustainable climate, energy, and environmental future. In this effort, a low-temperature water–gas shift reaction (WGSR) with Pt/Al₂O₃ catalysts is integrated with in situ carbon mineralization in a multiphase reaction environment. The hypothesis that Pt-based catalysts favor selective formation of H₂ over CH₄ has been investigated. H₂ yields increased by 30.8%, 9.5%, 8.3%, and 1.7% in the presence of Ca(OH)₂, Mg(OH)₂, Mg₂SiO₄, and CaSiO₃ relative to the blank experiment without the sorbent at constant experimental conditions of 250 °C and reaction time of 12 hours in the presence of Pt/Al₂O₃ catalyst with initial CO and N₂ pressures of 8 bar and 12 bar, respectively. These studies unlock the feasibility of advancing single-step multiphase pathways for enhancing H₂ yields with inherent CO₂ capture and mineralization for a low carbon and sustainable energy and resource future.