Importance of Electron Mediator Transparency: Photocatalytic Hydrogen Production from Polyoxometalate using Dye‐double‐layered Photocatalysts

Abstract

One-directional electron transfer is crucial for two-step photoexcitation (Z-scheme) water-splitting photocatalysis. We investigated the hydrogen evolution activity of PS-double-layered photocatalysts (X-DSP, X-RuCP 6 -Zr-RuP 6 @Pt/K x H 4-x Nb 6 O 17 ; X = Zr 4 + , H + ) in the presence of highly charged polyoxometalates-(Mn II -POM)-as redox-reversible electron donors, to induce effective photocatalyst-donor electrostatic attraction. Surfacephosphonate-comprising H + -DSP completely one-electron oxidized V IV -POM with 0.39 % apparent quantum yield in the initial hour (iAQY) in both HCl and phosphate buffer aqueous solutions. Conversely, the Zr 4 + -DSP iAQY decreased to 0.05 % in HCl aq. Considering that the 0.39 % iAQY was retained when replacing V IV -POM with Mn II -POM in HCl aq, we supposed that energy transfer deactivation from photoexcited PS* to surfaceimmobilized V IV -POM is the plausible origin of the lower iAQY, owing to the stronger visible-light absorptivity of V IV -POM. This suggests that accumulation of visible-light-transparent electron mediator on the photocatalyst surface is an effective approach for one-directional electron transfer in Z-scheme water-splitting photocatalysis.

Surface sensitization of g-C3N4/TiO2via Pd/Rb2O co-catalysts: accelerating water splitting reaction for green fuel production in the absence of organic sacrificial agents

“…In the current research, a high rate of hydrogen production by Pd-Rb 2 O@g-C 3 N 4 /TiO 2 was observed, indicating that the back reaction was completely suppressed. 67…”

Polyoxometalate‐Based Frameworks: Construction Strategies and Photocatalytic Applications

“…In terms of catalysis, these materials could serve as Brønsted acids and possess tunable redox potentials enable efficient charge separation and multielectron transfer processes with other species under mild conditions, and thus play a crucial role in the field of photocatalysis. [21][22][23][24][25][26] However, the features of good solubility and easily transferred structural patterns have posed limitations on the widespread application of POMs in catalytic systems. It may lead to undesired leaching or migration of active species during the catalysis, which might compromise the efficiency and stability of the POMs-based catalysts.…”

“…Moreover, POMs can be easily modified by incorporating different functional groups or metal ions, allowing for tailored properties and enhanced functionalities. In terms of catalysis, these materials could serve as Brønsted acids and possess tunable redox potentials enable efficient charge separation and multielectron transfer processes with other species under mild conditions, and thus play a crucial role in the field of photocatalysis [21–26] . However, the features of good solubility and easily transferred structural patterns have posed limitations on the widespread application of POMs in catalytic systems.…”