Van der Waals Interaction Really Matters: Energetics of Benzoic Acid on TiO₂ Rutile Surfaces

Abstract

Density functional theory (DFT) has been applied to elucidate the adsorption structures and energetics of benzoic acid on TiO 2 (110), (100), and (011) rutile surfaces. We demonstrate that ab initio calculations of interacting carboxylic acids require an exchangecorrelation functional with van der Waals (vdW) correction to yield reliable results, even for very small aliphatic species like acetic acid. On the (110) surface, benzoates dimerize due to intermolecular vdW interaction and form a 2 × 2 superstructure, which explains experimental findings already reported in the literature. The lateral vdW attraction between benzoates is even enhanced on ( 100) and ( 011) surfaces because of advantageous substrate periodicities, resulting essentially in only one geometrical adsorbate species.

A first-principles analysis of the charge transfer in magnesium corrosion

“…Since van der Waals (vdW) interactions are a key factor in hydrogen evolution reactions (HERs) 53 , the exchange-correlation (XC) functional optB88-vdW [54][55][56][57][58][59] was employed for all DFT computations. This functional accounts for dispersion interactions in an approximate fashion by including a non-local correlation part in the exchange-correlation energy and is expected to capture well the subtle energetic contributions of hydrogen bonded systems in solid-liquid interfaces 53,60,61 .…”

Adsorption of Acetone on Rutile TiO2: A DFT and FTIRS Study

“…Even though the binding energies depend sensitively on the employed XC functional, the energetic tendencies and relations between the different geometries remain the same. Since the optB88-vdW functional is expected to adequately represent the energetic impact of the adsorbed molecule, 9 it is used for further computations. Enhanced and more directional interactions of the methyl groups with neighboring bridging oxygen atoms are found for the rot max geometry comparing the differences of electron charge densities for the ⊥ and rot max geometries (see Figure 2).…”

“…For a more comprehensive understanding of the adsorption behavior of acetone on a rutile TiO 2 (110) surface, density functional theory (DFT) calculations were performed using the plane-wave code Vienna Ab Initio Simulation Package (VASP) − with the projector augmented wave (PAW) method. , Since van der Waals (vdW) interactions can be significant in the adsorption of organic molecules, the exchange-correlation (XC) functional optB88-vdW − was used for all DFT calculations in this work. This functional belongs to the group of van der Waals density functionals (vdW-DF), based on an approach by Dion et al Within this approach, vdW interactions are accounted for without the use of external input parameters.…”

“…The adsorption and possible subsequent chemical decomposition of acetone on titania (TiO 2 ) surfaces are of broad interest because of their relevance in various processes ranging from photocatalysis − to the remediation of airborne acetone contaminants. , At hybrid interfaces between inorganic surfaces and organic linker molecules, acetone may act as a competitor to coupling agents like carboxylic acids. − Thus, a detailed understanding of the relevant adsorption phenomena is crucial. In general, acetone is present in numerous chemical processes because of its usage as solvent or reagent .…”

Shape-controlling effects of hydrohalic and carboxylic acids in TiO2 nanoparticle synthesis

“…Calculations on hydrohalic acid adsorption and substitution were performed using symmetric surface slabs with 10 layers of TiO 2 , whereas asymmetric slabs with only 6 or 7 layers of TiO 2 were used to study carboxylic acid adsorption with reduced computational costs. Since van-der-Waals interactions cannot be neglected for the carboxylic acids, 26 the optB88-vdW exchange and correlation (XC) functional 27,28 was used for all calculations. A detailed comparison with the PBE (Perdew-Burke-Ernzershof) XC-functional 29 can be found in the supplementary material.…”