Abstract
Biomass gasification represents a promising pathway for renewable hydrogen generation, yet the resulting raw syngas typically exhibits high carbon monoxide concentrations and insufficient hydrogen-to-carbon ratios, requiring downstream water-gas shift (WGS) catalysis. Conventional WGS catalysts, such as iron-chromium and copper-zinc formulations, suffer from rapid thermal sintering, sulfur deactivation, and significant carbon deposition under harsh syngas operating conditions. In this study, we investigated the catalytic activity and durability of transition metal-functionalized metal-organic frameworks (MOFs) for syngas-to-hydrogen upgrading. A series of zirconium-based frameworks (UiO-66-NH2) incorporating dispersed nickel active sites (Ni@UiO-66-NH2) were synthesized via solvothermal protocols and post-synthetic modification. Catalytic evaluations were conducted in a continuous-flow fixed-bed reactor using simulated biomass gasification syngas (comprising CO, H2, CO2, CH4, and trace contaminants) at temperatures between 240 °C and 380 °C. The optimized 7 wt% Ni@UiO-66-NH2 catalyst demonstrated superior catalytic performance, achieving an 89.4% CO conversion and an exceptional hydrogen production rate of 42.6 mmol gcat⁻¹ h⁻¹ at 320 °C, outperforming reference commercial Cu-Zn-Al formulations under identical conditions. Detailed post-reaction characterization via X-ray photoelectron spectroscopy, N2 physisorption, and transmission electron microscopy revealed that the coordinatively unsaturated metal centers and the porous organic framework effectively suppressed nanoparticle sintering and coking. These findings underscore the viability of structurally engineered MOFs as high-performance, durable catalysts for sustainable biomass-derived hydrogen production.
