Spark Plasma Sintering Treatment for Introduction of Oxygen Vacancy in Pt Dispersed SrTiO₃ for Increasing Photocatalytic Water Splitting Activity

Abstract

Spark plasma sintering (SPS) treatment was studied for Pt dispersed SrTiO 3 as photocatalytic water splitting catalyst. The oxygen vacancy was introduced by SPS treatment and it was found that H 2 formation rate was increased by SPS treatment since large amount of oxygen vacancy was introduced. H 2 formation rate became the highest (6.15 mmol h À 1 g À 1 ) at 2.5 wt% Pt dispersed on SrTiO 3 and this H 2 formation rate was almost double of Pt loaded SrTiO 3 and O 2 formation rate was also much increased (5.66 mmol h À 1 g À 1 ). ESR measurement suggests that amount of Ti 3 + was intense after SPS treatment with 2.5 wt% Pt. Therefore, it seems that the oxygen vacancy introduced by SPS treatment effectively worked for charge separation and photocatalytic activity of SrTiO 3 to water splitting was increased.[a] Y.

Gigantic electro-chemo-mechanical properties of nanostructured praseodymium doped ceria

“…Moreover, the chemical reducing conditions during the SPS can consolidate oxygen vacancies at the nanocrystalline grain boundaries disorder with stable Pr 3+ and Ce 3+ ions population. 30,51 Such a compositional inhomogeneity can result in a change in the charge transport mechanisms. In Fig.…”

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

“…Spark plasma sintering or lowtemperature hydrothermal treatment may overcome such shortcoming. Kim et al [158] took advantage of simultaneous heat and pressure during spark plasma sintering to create reducing atmosphere to induce the formation of oxygen defect on the surface of SrTiO 3 , and introducing oxygen defect doubled the photocatalytic H 2 generation activity of Pt-deposited SrTiO 3 to 6.15 mmol h −1 g −1 .…”

“…Kim et al. [ 158 ] took advantage of simultaneous heat and pressure during spark plasma sintering to create reducing atmosphere to induce the formation of oxygen defect on the surface of SrTiO 3 , and introducing oxygen defect doubled the photocatalytic H 2 generation activity of Pt‐deposited SrTiO 3 to 6.15 mmol h −1 g −1 . Our group [ 159 ] developed a post‐hydrothermal method with glyoxal as reducing agent to prepare surface oxygen vacant Sr 2 Bi 2 Nb 2 TiO 12 and the density of defects was enhanced with the increasing using amount of glyoxal.…”

The crucial role of defect structure in understanding the electrical properties of spark plasma sintered antimony doped barium stannate

“…In the materials preparation process, apart from doping, sintering conditions have a significant impact on electrical properties of final material. For example, sintering in the oxygen-poor atmosphere leads to the formation of oxygen vacancies as native intrinsic defects in ceramics, thus improving their electrical conductivity [7][8][9][10]. Spark plasma sintering (SPS) is a current and pressure assisted technique that takes place under vacuum conditions in a graphite die.…”

“…Combination of sintering conditions and the volatile nature of tin could result in the reduction of Sn 4+ into Sn 2+ , or even to metallic Sn. As stated before, SPS favors the creation of oxygen vacancies [7][8][9][10][26][27][28], which behave as electron donors and improve the materials electrical conductivity with a maximum of two electrons (per vacancy) [5,6,[15][16][17]29]. Compared to other intrinsic defects formed under poor oxygen conditions, they have the lowest formation energy, and their presence is the most expected in BSSO samples.…”