Sr₂NiWO₆ Double Perovskite Oxide as a Novel Visible-Light-Responsive Water Oxidation Photocatalyst

Abstract

Screening of stable visible-light-responsive water oxidation semiconductor photocatalysts is highly desired for the development of photocatalytic water splitting systems. Herein, a visible-light-absorbing Sr2NiWO6 double perovskite oxide photocatalyst was successfully prepared via a conventional solid-state reaction method. The intrinsic Sr2NiWO6 shows photocatalytic oxygen evaluation reaction (OER) activity of 60 μmol h–1 g–1, even without loading any cocatalysts. The DFT calculation indicates that the Ni species on the surface is the active site for the OER. The photocatalytic OER activity was further improved by loading Pt and RuO2 dual redox cocatalysts on the surface of Sr2NiWO6 to achieve a photocatalytic OER activity of 420 μmol h–1 g–1, which corresponds to a remarkable apparent quantum efficiency (AQE) of 8.6% (λ ≈ 420 nm). The result indicates that Sr2NiWO6 is one of the best double perovskite oxide-based photocatalysts for the photocatalytic OER, and the activity is even comparable to the benchmark BiVO4-based photocatalyst. The improvement of the photocatalytic OER activity is due to the provision of more active redox sites as well as the synergetic effect of the dual redox cocatalysts in facilitating charge separation and transfer. This work demonstrates that double perovskite oxides may serve as a novel class of efficient and stable oxide-based semiconductor photocatalysts for water splitting.

A Novel Visible‐Light‐Responsive Semiconductor ScTaO4−xNx for Photocatalytic Oxygen and Hydrogen Evolution Reactions

“…To determine the band edge positions, the flat‐band potential of the ScTaO 4 and ScTaO 4−x N x samples were firstly evaluated from the Mott‐Schottky (MS) plots in an aqueous Na 2 SO 4 solution (pH=7). As shown in Figure 2d and Figure S6, MS plots with positive slope imply the as‐prepared ScTaO 4 and ScTaO 4−x N x are n‐type conducting semiconductors, [30] and the flat band potential can be calculated to be ca. −0.08 and −0.10 V vs. NHE (pH=0), respectively.…”

Two-Dimensional Layered Co(OH)2/g-C3N4/Ni(OH)2 Ternary Nanocomposites for Enhanced Visible-Light Photocatalytic H2-Production Activity

“…To promote the activity of g-C 3 N 4 and make it more practical, numerous strategies have been developed, including nanostructure engineering, metal/nonmetal doping, protonating by strong acids, and fabrication of heterojunction composites. − Moreover, it is confirmed that surface modification with proper cocatalysts is a valid way to accelerate charge separation and reduce the activation energy for H 2 or O 2 evolution, leading to an excellent photocatalytic activity . However, to date, the most commonly used cocatalysts are still those rare and expensive noble metals and oxides (such as Pt, Pd, and RuO 2 ), which greatly restricts their practical applications. , Considering the cost and practicability, it is meaningful to develop high active cocatalysts without noble metals.…”

“…14 However, to date, the most commonly used cocatalysts are still those rare and expensive noble metals and oxides (such as Pt, Pd, and RuO 2 ), which greatly restricts their practical applications. 15,16 Considering the cost and practicability, it is meaningful to develop high active cocatalysts without noble metals.…”

Regulation of Ferroelectric Polarization to Achieve Efficient Charge Separation and Transfer in Particulate RuO2/BiFeO3 for High Photocatalytic Water Oxidation Activity

“…A variety of strategies have been explored to achieve efficient charge separation and transfer in semiconductor photocatalysis, such as heterojunction, [ 3 ] phase junction, [ 4 ] Z‐scheme, [ 5 ] and deposition of appropriate redox cocatalysts on the surface of semiconductor photocatalysts. [ 6–8 ] We are particularly interested in engineering and exploiting the intrinsic electric field of semiconductor as driving force for separation of photogenerated charges, and further enhance the photocatalytic activity by combination with the above mentioned traditional strategies. For example, we have shown that photogenerated charges can be efficiently separated on the different facets of a single semiconductor nanocrystal driven by in situ generated internal electric field, and spatial loading of redox cocatalysts on the different facets results in dramatically improvement of photocatalytic water oxidation activity.…”