Influence of the oxygen-vacancy promoter on the CeO2-supported Ni catalyst for self-reforming of corn straw pyrolysis volatiles

Thermochemical conversion of lignocellulosic biomass into syngas contributes to renewable hydrogen and carbon utilization, advancing the development of carbon-neutral energy solutions. However, the current biomass gasification process suffers from high energy consumption due to the need for excessive steam input. In this study, a series of CeO 2 -supported Ni catalysts with tailored oxygen vacancy concentrations was prepared by doping Gd, Zr, and La as promoters into the support, aiming to enable the catalytic self-reforming of real biomass volatiles without exogenous steam. Comprehensive characterization techniques, including electron paramagnetic resonance (EPR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), revealed the critical role of surface oxygen vacancy concentration in determining the catalytic activity. The optimized 10Ni/CeLaO 2 catalyst achieved a total crude syngas yield of 15.4 mmol·g straw −1 at 700 °C, which is 70.4% higher than the non-catalytic system and 20.1% higher than undoped 10Ni/CeO 2 . Moreover, it also exhibits excellent stability with 87.3% oxygen vacancy retention and minimal carbon deposition (0.09 g g H2 −1 ) after reaction. This study provides key insights into the potential of employing oxygen vacancy engineering for efficient biomass thermochemical conversion without exogenous steam input.