Structure–Activity Correlation and Reaction Optimization of H ₂ Production by Ethanol Steam Reforming over Engineered La–Ni/Al ₂ O ₃ Catalysts

We developed La-promoted Ni/Al 2 O 3 catalysts to operate effectively in hydrogen generation through the ethanol steam reforming (ESR) process. The catalysts were produced through the excess solution impregnation method, which enabled researchers to achieve uniform metal distribution and optimal metal support interaction at Ni concentrations between 0.55 and 2.8 wt % and La concentrations between 0.25 and 1.2 wt %. The complete structural and surface analysis results showed that La addition to the material increased Ni distribution, raised the surface concentration of La 3+, and created oxygen vacancies, thereby enhancing the material’s redox performance. The (2.8 wt %) Ni–(1.2 wt %) La/Al 2 O 3 catalyst reached a hydrogen production rate of 96.52% at 350 °C under fixed-bed ESR conditions with an S/C ratio of 3 and a temperature range of 250–350 °C. The structure–activity correlations observed under practical conditions indicate that La promotion shifts the reaction pathway toward reforming processes while reducing CH 4 formation and carbon deposition. We investigated the kinetic behavior of ESR through our studies of Ni–La/Al 2 O 3 catalysts across the temperature range from 250 to 350 °C. The experimental results presented are well compatible with both the power-law kinetic model and the Langmuir–Hinshelwood–Hougen–Watson (LHHW) mechanistic model. Activation energies computed for the reaction ESR were 77.902 kJ/mol, and also for LHHW, 73.01 kJ/mol.