(A) The intermediate speciation and chemistry of the photocatalytic toluene oxidation on 120-β-Ga₂O₃ [73]; (B) proposed C7 conversion pathway and calculated reaction energies of hydroxyl induced toluene photooxidation on catalysts [74]; (C) schematic illustration for different paths of photocatalytic gas toluene degradation [75]; (D) the illustration of roles of methyl number on mechanisms and performance of photocatalytic decomposition of benzene, toluene, and o-xylene [76]. GC-MS chromatogram for the determination of reaction intermediates in the gas-phase photocatalytic decomposition of toluene: as a single individual component (E) and as part of a mixture of CH₂O and C₇H₈ (F) [31]; (G) diagram of Gibbs free energy variation on the SnO₂ surface [31].