Influence of various catalysts on H₂ enhancement and CO2 capture during syngas upgrading

Biomass gasification represents a promising thermochemical route for the valorization of agro-forestry residues, offering a sustainable alternative to conventional waste-management practices while enabling the production of a versatile fuel: syngas. This gas mixture, typically composed of H₂, CO, CO₂ and CH₄ in variable proportions, can be used for heat and power generation or as a precursor for the synthesis of value-added chemicals. However, the raw syngas derived from biomass gasification often contains undesired species and exhibits suboptimal H₂ concentrations, limiting both its energetic performance and its suitability for downstream applications. Catalyst-assisted syngas upgrading has therefore become an area of increasing scientific interest, as it provides a pathway to selectively enhance hydrogen content while reducing CO₂ and other unwanted components. Different classes of catalytic and adsorbent materials can promote reactions such as CO₂ capture, reforming of light hydrocarbons, and water–gas shift, ultimately leading to a cleaner and more hydrogen-rich syngas. In this study, a controlled synthetic gas mixture with known concentrations of H₂, CO, CO₂, CH₄ and N₂ was employed to systematically investigate the behavior of several candidate materials—specifically CaO, MgO, CuO and Li₂ZrO₃. Experiments were carried out in a laboratory-scale reactor designed to evaluate the influence of material properties and operating conditions on syngas composition. The focus of the analysis was twofold: (i) to identify the extent to which each material can enhance hydrogen concentration through catalytic or sorptive effects, and (ii) to examine the advantages, limitations and potential synergies associated with their use under conditions representative of biomass gasification environments. Beyond highlighting the materials’ individual performance, the study contributes to a broader understanding of how solid catalysts and sorbents can support the development of more efficient, flexible and sustainable gasification-based energy systems.