La–Ni Modified Calcined Dolomite for Enhanced Hydrogen Production from Biomass Gasification: A Combined Experimental and DFT Study

This study investigates the enhancement of hydrogen production from corn stalk gasification using modified calcined dolomite (CD) catalysts. A Ni/CD catalyst was first synthesized, followed by La2O3 promotion to produce La–Ni/CD. Both catalysts were evaluated for gasification performance, anticoking ability, and cyclic stability. Results show that La–Ni/CD significantly improved hydrogen yield to 166.7 mL/g, surpassing unmodified CD (110.3 mL/g), and maintained 138.9 mL/g after seven cycles. Complementary density functional theory (DFT) simulations via CASTEP revealed that La modification induced a shift of the Ca-p and O-s electronic states to lower energies. This electronic redistribution promotes H-s and Ni-p orbital hybridization, thereby enhancing H2 adsorption. Bond population analysis confirmed strengthened O–La bonds (population: 0.50) and stabilized H–C bonds (0.80–0.84), while reduced O–Ni populations mitigated carbon deposition. These synergistic effects demonstrate the role of La–Ni/CD in optimizing pathways toward hydrogen-rich syngas, supporting its potential for efficient biomass gasification.