Oxygen Evolution Reaction (OER) on Clean and Oxygen Deficient Low-Index SrTiO₃ Surfaces: A Theoretical Systematic Study

Abstract

SrTiO3 (STO) is a widely used photocatalyst for water splitting, which has no photoactivity without a cocatalyst. The reason for this unclear. Here, we performed an oxygen evolution reaction (OER) on clean and oxygen deficient (100), (110), and (111) surfaces on STO by density functional theory. Combining our results with experimental results in the literature, we demonstrated that the overpotential is small enough for OER to occur on (100) surfaces. There is no photoactivity due to the photogenerated holes that cannot migrate to the (100) surfaces. On the (110) and (111) surfaces, the overpotential is very high, which prevents the OER from taking place on these two surfaces. Our work gives a guidance principle to understand the water splitting from the overpotential of OER and migrating photogenerated carriers. It may be helpful to design high efficiency photocatalysts based on STO.

Water Splitting on Multifaceted SrTiO3 Nanocrystals: Calculations of Raman Vibrational Spectrum

“…According to recent developments, the photogenerated charge is shared between different facets of a semiconductor crystals with low symmetry [19,20]. Among other materials for water splitting, strontium titanate SrTiO 3 (STO) is well known [15,18,[21][22][23][24][25][26][27][28][29][30], where the processes of water adsorption and dissociation have been studied in detail [31][32][33]. Despite the fact that many semiconductor crystals are highly symmetric and have isotropic facets that are not suitable for charge separation between faces, it was found that the selective distribution on the anisotropic faces of 18-facet strontium titanate nanocrystals leads to a noticeable increase of apparent quantum efficiency [9].…”

Synergistic effect of p-type and n-type dopants in semiconductors for efficient electrocatalytic water splitting

“…It also shows outstanding chemical stability but its OER-related electrocatalytic activity is rather low, in part also due to its wide bandgap. 38,39 As in the case of TiO 2 , Rh and V were used as the p-type and n-type dopant, respectively. The results of the thermodynamic analysis of the OER catalysis on pristine and doped SrTiO3 structures are summarized in Fig.…”

Water Splitting on Multifaceted SrTiO3 Nanocrystals: Computational Study

“…The HOO * adsorbate also had two configurations: one where hydrogen bonded to surface oxygen (Figure 5d), denoted as H (O surf ) OO * , and the other where hydrogen bonded to the adsorbate's oxygen (Figure 5e), denoted as HOO * . In [14], only the second configuration was mentioned, although its adsorption energy was significantly higher than that of the H (O surf ) OO * configuration: 4.24 eV versus 3.64 eV.…”

“…Strontium titanate SrTiO 3 (STO) is a well-known material for water splitting [1][2][3][4][5][6][7][8][9][10][11][12]. The process of water adsorption and dissociation was studied in detail [13][14][15]. The effects of doping are investigated in [16].…”

“…An extensive investigation of OER on the flat STO surface was performed by Cui et al [14]. For the flat {0 0 1}, the STO surface of the over-potential value of 0.66 V was obtained.…”