• Ilmenite oxygen carriers reduce devolatilization intensity during co-pyrolysis of corn straw and bituminous coal.
• Positive synergistic effects occur when corn straw blending ratio is below 50%, with optimal synergy at 30%.
• Solid–solid interaction between oxygen carriers and coke enhances co-pyrolysis reactivity at high temperatures (750–950 °C).
• Co-pyrolysis activation energy ranges from 26.35 to 40.57 kJ·mol⁻¹, indicating improved reaction kinetics.