Crystal facet engineering enhances photocatalytic NOx abatement selectivity

Crystal facet engineering is an important concept in material science but is yet to be explored direction of fabricating catalysts with improved selectivity. In this study, we prepared pure TiO₂ brookite nanorod catalysts exposed with a variation of (120), (111), and (110) active crystal domains for photocatalytic NOx (nitrogen oxides) abatement using TALH (C₆H₁₈N₂O₈Ti) titania precursor via a variation of sodium lactate (C₃H₅NaO₃) and urea (NH₄CNO) addition. The different characterization such as XRD, SEM, and TEM proved the high availability of (111) crystal facet and approximate equal presence of (120), (111), and (110) crystal domains in TALH-6U-SL resulting in up to 4.9-fold higher selectivity than commercial TiO₂-P25 as well as other brookite nanorod catalysts. TGA, FTIR, and XPS results demonstrated that compared to other catalysts, TALH-6U-SL nanorod catalyst adsorbs more water and contains more oxygen vacancies and crystal defects, thus boosting the photocatalytic selectivity for NOx conversion to NO₃⁻ ions.