A Novel Double Perovskite Oxide Semiconductor Sr2CoWO6 as Bifunctional Photocatalyst for Photocatalytic Oxygen and Hydrogen Evolution Reactions from Water under Visible Light Irradiation. Issue 3 (5th December 2019)

• Record Type: Journal Article
• Authors: Idris, Ahmed Mahmoud; Liu, Taifeng; Shah, Jafar Hussain; Zhang, Xianwen; Ma, Changtong; Malik, Anum Shahid; Jin, Ailing; Rasheed, Saadia; Sun, Yimeng; Li, Can; Han, Hongxian
• Is Part Of: Solar RRL. Volume 4:Issue 3(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-12-05
• Subjects: double perovskite oxides -- hydrogen evolution reactions -- oxygen evolution reactions -- photocatalytic water splitting -- visible light irradiation; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201900456
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Development of photocatalytic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) photocatalysts with a narrow bandgap is important for solar water splitting. Herein, narrow bandgap Sr2 CoWO6 double perovskites with a light absorption edge of ≥700 nm are synthesized by a solid‐state reaction method varying the precursor ratios. The sample synthesized with a precursor Co/W ratio of 1:4 has a conduction band (CB) and valence band (VB) located at −0.82 and 0.95 V versus the normal hydrogen electrode (NHE) at pH = 7, respectively. As a result, both the photocatalytic OER and HER are observed even without loading any cocatalysts. After loading Pt and Rh cocatalysts, the average photocatalytic OER and HER rates are 188 μmol h −1 g −1 (apparent quantum efficiency of 3% at ≈420 nm) and 30 μmol h −1 g −1, respectively. Density functional theory calculations indicate that the OER active sites may shift from a high overpotential W‐site to a low overpotential Co‐site when the W content is increased, which renders high photocatalytic activity for W‐rich samples. Therefore, W‐rich Sr2 CoWO6 double perovskite is identified as a novel narrow bandgap bifunctional semiconductor photocatalyst for photocatalytic OER and HER, which is rare for oxide semiconductor photocatalysts. This work opens up a new avenue for the development of oxide‐based double perovskite semiconductor photocatalysts for photocatalytic water splitting. Abstract : Sr2 CoWO6 double perovskite oxide is a bifunctional photocatalyst to drive photocatalytic oxygen evolution and hydrogen evolution half‐reactions efficiently under visible light irradiation in the presence of the sacrificial reagents, which demonstrate that double perovskite oxides have a great potential to open up a new avenue for the development of stable oxide‐based semiconductor photocatalysts for overall water splitting.