Low Temperature and Controllable Formation of Oxygen Vacancy SrTiO_3‐x by Loading Pt for Enhanced Photocatalytic Hydrogen Evolution

Abstract

Oxygen vacancy plays a key role in the photocatalytic processes of oxide semiconductors. However, it usually needs high hydrogenation temperature to form oxygen vacancy for SrTiO3. To decrease the temperature, Pt was preloaded on SrTiO3 to transform H2 into the active hydrogen through hydrogen spillover. As a result, the surface oxygen vacancy of Pt/SrTiO3‐x forms at low temperature to 150 °C. Without Pt loading, the defects of SrTiO3 cannot occur even at 400 °C. As the hydrogenation temperature increases, the surface oxygen vacancy of Pt/SrTiO3‐x rises, and a thin disorder overlayer on the facet loaded with metal Pt appears at 400 °C; whereas at 600 °C, besides the disorder overlayer, the surface defects at the facets without Pt and bulk defects are produced, indicating the controllable formation of oxygen vacancies. With the increasing of hydrogenation temperature, the activity of Pt/SrTiO3‐x enhances, and reaches the maximum at 400 °C. The produced H2 amount of Pt/SrTiO3‐x prepared at 400 °C is about 3 times as high as that of Pt/SrTiO3. The activity of Pt/SrTiO3‐x obtained at 600 °C is significantly lower than that at 400 °C. The surface oxygen vacancies are responsible for the enhanced activity; while the decreased specific surface and bulk defects produced at high hydrogenation temperature reduce the activity.

Versatile Titanates: Classification, Property, Preparation, and Sustainable Energy Catalysis

“…Furthermore, the atmosphere during calcination treatment has an influence on obtaining the targeted titanates. Peng et al [101] calcinated Pt/SrTiO 3 powder with 5% H 2 /N 2 mixed gas flow to construct oxygen vacancy, attributed to the introduction of reductive environment.…”

“…Peng et al. [ 101 ] calcinated Pt/SrTiO 3 powder with 5% H 2 /N 2 mixed gas flow to construct oxygen vacancy, attributed to the introduction of reductive environment.…”

“…Benefiting from high charge transfer and separation efficiency, rich active sites as well as high reduction ability, STO-NH treated at 600 °C for 3 h displayed much higher photocatalytic activity for H 2 generation compared with STO-N without oxygen vacancy (Figure 14c,d). Differing from the above work, Peng et al [101] adopted modified hydrogenation method and preloaded Pt on SrTiO 3 to build oxygen defect through hydrogen spillover effect, greatly decreasing the needed hydrogenation temperature to 150 °C. As hydrogenation temperature gradually rise up, the concentration of oxygen vacancy was altered to be higher constantly.…”

“…Differing from the above work, Peng et al. [ 101 ] adopted modified hydrogenation method and preloaded Pt on SrTiO 3 to build oxygen defect through hydrogen spillover effect, greatly decreasing the needed hydrogenation temperature to 150 °C. As hydrogenation temperature gradually rise up, the concentration of oxygen vacancy was altered to be higher constantly.…”

Perovskite Oxide Based Materials for Energy and Environment-Oriented Photocatalysis

“…SrTiO 3 is also widely explored for energy conversion as there are a large number of reports on SrTiO 3 based photocatalytic H 2 evolution. Bare SrTiO 3 with different strategies such as defect engineering, facet engineering, − 3D structure, and mesocrystal formation have been synthesized by the researchers to have enhanced photocatalytic H 2 evolution. Zhang et al have reported the synthesis of SrTiO 3 mesocrystals from TiO 2 mesocrystals by the hydrothermal method, through topotactic epitaxy .…”