Mo-modified ZSM-5 catalysts were prepared and used to produce aromatic hydrocarbons during catalytic fast pyrolysis (CFP) of biomass. The composition and distribution of aromatics were investigated on pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The reaction factors, such as the Mo content, the reaction temperature and the catalyst/biomass mass ratio, were also optimized. It was found that the 10Mo/ZSM-5 catalyst displayed the best activity in improving the production of monocyclic aromatic hydrocarbons (MAHs) and decreasing the yield of polycyclic aromatic hydrocarbons (PAHs) at 600 °C and with a catalyst/biomass ratio of 10. Furthermore, according to catalyst characterization and the experiment results, the aromatics formation mechanism over Mo/ZSM-5 catalysts was also summarized and proposed.

Biomass thermochemical conversion with in situ CO₂ capture is a promising technology in the production of high-quality gas. The adsorption competition mechanism of gas molecules (H₂O, CO₂, CO, CH₄, and H₂) on CaO-based catalyst surfaces was studied using density functional theory (DFT) and experimental methods. The adsorption characteristics of CO₂ on CaO and 10 wt % Ni/CaO (100) surfaces were investigated in a temperature range of 550–700 °C. The adsorption energies were increased and then weakened, reaching their maximum at 650 °C. The simulation results were verified by CO₂ temperature-programmed desorption (CO₂-TPD) experiments. By the density of states and Mulliken population analysis, CaO doped with Ni caused a change in the electronic structure of the O_surf atom and decreased the C–O bond stability. The molecular competition mechanism on the CaO-based catalyst surface was identified by DFT simulation. As a result, the adsorption energies decreased in the following order: H₂O > CO₂ > CO > CH₄ > H₂. The increase of CO₂ adsorption energy on the 10 wt % Ni/CaO surface, compared with the CaO surface, was the largest among those of the studied molecules, and its value increased from 1.45 eV to 1.81 eV. Therefore, the 10 wt % Ni/CaO catalyst is conducive to in situ CO₂ capture in biomass pyrolysis.

Summary: Fe‐modified ZSM‐5 (Fe/ZMS‐5) catalysts were prepared and used during catalytic fast pyrolysis of biomass (CFP) to achieve high yields of monocyclic aromatic hydrocarbons (MAHs) and inhibit the formation of polycyclic aromatic hydrocarbons (PAHs). The catalytic effects on the yield and selectivity of aromatic hydrocarbons (aromatics) under various reaction conditions were evaluated. Under the optimal reaction conditions at 600°C and mass ratio of catalyst to biomass (catalyst/biomass) of 10/1, the 15 wt% Fe/ZMS‐5 catalyst displayed the highest productions of MAHs and PAHs with the values of 212.2 mg and 94.5 mg per gram biomass, corresponding to the MAHs selectivity of 69.2%, which were significantly higher than those obtained over ZSM‐5 alone. The origins of aromatic hydrocarbons were explored by CFP of three typical components of biomass. Combined the characterization and reaction performance of catalysts, the catalytic mechanisms of Fe/ZSM‐5 catalyst for biomass pyrolysis to produce aromatic hydrocarbons were put forward.