Texturally Modified Zirconia–Tungstophosphoric Acid Catalysts for Efficient Lignocellulosic Pyrolysis

This work presents the synthesis, characterization, and application of zirconium oxide (ZrO2)-based catalysts, modified with macro (silica nanospheres, NSP-SiO2) and mesopore templates (Pluronic 123), impregnated with tungstophosphoric acid (TPA), in the catalytic pyrolysis of tomato agro-industrial residues. The NSP-SiO2 (SXX) and P123 (PYY) amount mainly influences the ZrO2SXXPYY-specific surface area (SBET) and average pore diameter (Dp). 31P MAS NMR and FT-IR characterization results show that TPA (H3PW12O40) was partially transformed into [P2W21O71]6− and [PW11O39]7− during the synthesis steps. The acidic properties of ZrO2SXXPYY samples containing 25 and 50 wt% of TPA (ZrO2SXXPYYT25 and ZrO2SXXPYYT50, respectively) are dependent on both the TPA content and the support nature. Bio-oil composition and product selectivity were strongly influenced by the textural and acid-based properties of the catalysts. Notably, non-catalytic pyrolysis favored pathways leading to C2 compounds, with a high content of acetic acid and hydroxyacetone. In contrast, the use of catalysts promoted the formation of higher molecular weight oxygenated compounds (C5–C6), specifically furans, aldehydes, and ketones.