Sorption-enhanced gasification for hydrogen production: A systematic review of sorbent functionality and process configuration

As demand for sustainable energy grows and decarbonization of energy systems accelerates, sorption-enhanced gasification (SEG) has emerged as a promising thermochemical pathway for hydrogen production with simultaneous in-situ CO2 capture. However, existing studies predominantly evaluate SEG performance in isolation, with limited integration of sorbent functionality and process configuration, which constrains systematic comparison across studies and the evaluation of scale-up potential. This review addresses this gap by systematically evaluating major SEG configurations, including conventional SEG, sorption-enhanced water-gas shift, reformer-integrated systems, and chemical looping variants. A PRISMA-guided literature review was conducted using the Scopus database, covering studies published from 2015 to 2026, with 73 studies included after screening. CaObased sorbents typically achieve hydrogen concentrations of 65-85 vol% under optimized conditions, although performance declines above 750 degrees C due to sintering. Modified sorbents, including doped CaO composites and redox-active materials, demonstrate enhanced cyclic stability and hydrogen purities of up to 90%. Hydrogen enhancement is governed by the interplay amongst carbonation kinetics, sorbent stability, and process configuration, while persistent challenges such as sorbent deactivation and regeneration energy penalties highlight the need for durable sorbent design and improved system-level integration. This review contributes to a unified framework linking sorbent properties with process design and performance, enabling more consistent evaluation of SEG systems and supporting their optimization and scale-up.