Faria Letícia Carolaine Silva, de Queiroz Letícia Marques de Souza Vetrano, Bihain Murielly Fernanda Ribeiro, Pereira Douglas Henrique, Ueno Leonardo Tsuyoshi, Machado Francisco Bolivar Correto, Ferrão Luiz Fernando de Araujo
Aeronautics Institute of Technology (ITA), São José dos Campos, SP, Brazil.
Department of Chemistry, Federal University of Tocantins (UFT), Gurupi, TO, Brazil.
J Comput Chem. 2025 Sep 30;46(25):e70232. doi: 10.1002/jcc.70232.
Small titanium dioxide clusters (with = 1-10) are promising photocatalysts for conversion; however, their size-dependent stability and reactivity are not fully characterized. This study uses density functional theory (M06/def2-TZVP) and global and local reactivity descriptors to identify "magic number" clusters that exhibit high stability. The stability function ( ), reveals = 2, 4, and 8 as magic numbers. Electrophilicity analysis ( ) shows moderate electrophilicity for = 1-5 and strong electrophilicity for = 7-10, while the magic numbers display reduced reactivity. Fukui functions and fractional occupation number-weighted density ( ) highlight localized reactivity. Notably, they reveal = 6 to be highly electrophilic, with distinct "hot" electron sites. interaction energies inversely correlate with cluster stability: unstable clusters ( = 3, 5, and 9) strongly bind (up to 0.72 eV), while magic numbers weakly physisorb it (e.g., 0.45 eV for = 8). Non-covalent interaction (NCI) analysis confirms Ti-OCO attraction and C-repulsive sites. Together, these results establish design principles for cluster catalysts that balance stability with tailored reactivity for activation.
小尺寸的二氧化钛簇（(n = 1 - 10)）是用于(CO_2)转化的有前景的光催化剂；然而，它们尺寸依赖的稳定性和反应活性尚未得到充分表征。本研究使用密度泛函理论（M06/def2-TZVP）以及全局和局部反应性描述符来识别具有高稳定性的“幻数”簇。稳定性函数（(S(n))）揭示(n = 2)、(4)和(8)为幻数。亲电性分析（(\omega)）表明(n = 1 - 5)时具有中等亲电性，(n = 7 - 10)时具有强亲电性，而幻数显示出降低的反应活性。福井函数和分数占据数加权密度（(f(n))）突出了局部反应性。值得注意的是，它们揭示(n = 6)具有高亲电性，有明显的“热点”电子位点。(CO_2)相互作用能与簇的稳定性呈负相关：不稳定的簇（(n = 3)、(5)和(9)）与(CO_2)强烈结合（高达(0.72) eV），而幻数对其物理吸附较弱（例如，(n = 8)时为(0.45) eV）。非共价相互作用（NCI）分析证实了Ti - OCO吸引位点和C - 排斥位点。总之，这些结果确立了用于(CO_2)簇催化剂的设计原则，该原则在稳定性与针对(CO_2)活化的定制反应活性之间取得平衡。
