Silver-Inserted Heterojunction Photocatalysts for Z-Scheme Overall Pure-Water Splitting under Visible-Light Irradiation

Abstract

Overall pure-water splitting under visible-light irradiation was accomplished utilizing a solid-state heterojunction photocatalyst following the Z-scheme mechanism. Zinc rhodium oxide (ZnRh2O4) and defective silver antimonate (Ag1–x SbO3–y ) as hydrogen (H2)- and oxygen (O2)-evolution photocatalysts, respectively, were connected with silver (Ag) to prepare a solid-state Z-scheme photocatalysis system (ZnRh2O4/Ag/Ag1–x SbO3–y ). In this system, Ag acted as a solid-state electron mediator for the transfer of electrons from the conduction band of Ag1–x SbO3–y to the valence band of ZnRh2O4. Utilizing the thus-constructed ZnRh2O4/Ag/Ag1–x SbO3–y photocatalyst, the simultaneous liberation of H2 and O2 from pure water at a molar ratio of ∼2:1 was achieved under irradiation with visible light at over 500 nm.

Visible-light-sensitive two-step overall water-splitting based on band structure control of titanium dioxide

“…However, because the evolution rates were not high, it is necessary to further enhance the visible-light sensitivity of these TiO 2 -based materials by optimizing the concentrations and types of dopants or by preparing deficient-free doped TiO 2 . We have recently developed a solid-state two-step overall water-splitting photocatalyst, in which the H 2 -and O 2 -evolution photocatalysts were connected via silver [27]. In this system, distilled water could be split without a redox mediator.…”

Thermoelectric Properties of Silver Antimonate with Mixed Valency of Antimony

“…The σ values of both samples increased with increasing temperature, which is typical semiconductor behavior. In Figure 4( 10 ), closed electronic-shell configuration). However, the opposite experimental results were observed.…”

“…However, the previous studies, regarding TE properties of AgSbO 3 , did not mention the existence of metallic Ag. Moreover, the valency of Sb (Sb 3+ (4d 10 ), Sb 5+ (4d 10 5s 2 )) should affect σ due to generation of oxygen vacancy in the presence of Sb 3+ ; however such discussion has not been performed. Thus, in the present paper, we characterize the AgSbO 3 in details, prepared by the combination of a solid state reaction (SSR) method and a nitric acid (HNO 3 ) treatment [10].…”

“…Moreover, the valency of Sb (Sb 3+ (4d 10 ), Sb 5+ (4d 10 5s 2 )) should affect σ due to generation of oxygen vacancy in the presence of Sb 3+ ; however such discussion has not been performed. Thus, in the present paper, we characterize the AgSbO 3 in details, prepared by the combination of a solid state reaction (SSR) method and a nitric acid (HNO 3 ) treatment [10]. In addition, the existence of metallic silver and the ratio of Sb 3+ /Sb 5+ in AgSbO 3 are discussed in connection with σ, S, and κ.…”

Loading of Co3O4 onto Pt-modified nitrogen-doped TiO2 nanocomposites promotes photocatalytic hydrogen production

“…16,17 At the same time, application of cocatalyst was found to be effective in reducing the recombination of photo generated electron and holes. 18,19 Thus far, many studies have reported that loading of noble metals such as Au, 20,21 Ag, 22 Pt, 23 and Rh 24 on the surface of a semiconductor as a co-catalyst plays an important role in photocatalytic water splitting, which revealed that high H 2 production is due to the electron trapping properties of noble metals. Application of Pt has been extensively studied because an appropriate Schottky barrier is found in it, which is benecial for H + reduction.…”