scholarly journals Photocatalyst Z-scheme system composed of a linear conjugated polymer and BiVO4 for overall water splitting under visible light

2020 ◽  
Vol 8 (32) ◽  
pp. 16283-16290 ◽  
Author(s):  
Yang Bai ◽  
Keita Nakagawa ◽  
Alexander J. Cowan ◽  
Catherine M. Aitchison ◽  
Yuichi Yamaguchi ◽  
...  

A Z-scheme of a linear conjugated polymer photocatalyst and a metal oxide is able to facilitate overall water splitting without non-scalable sacrificial reagents showing potential for sustainable hydrogen production.

2020 ◽  
Vol 142 (18) ◽  
pp. 8412-8420 ◽  
Author(s):  
Takayoshi Oshima ◽  
Shunta Nishioka ◽  
Yuka Kikuchi ◽  
Shota Hirai ◽  
Kei-ichi Yanagisawa ◽  
...  

2020 ◽  
Author(s):  
Yang Bai ◽  
Keita Nakagawa ◽  
Alexander Cowan ◽  
Catherine Aitchison ◽  
Yuichi Yamaguchi ◽  
...  

<p>Linear conjugated polymers have potential as photocatalysts for hydrogen production from water but so far, most studies have involved non-scalable sacrificial reagents. Z-schemes comprising more than one semiconductor are a potential solution, but it is challenging to design these systems because multiple components must work together synergistically. Here, we show that a conjugated polymer photocatalyst for proton reduction can be coupled in a Z-scheme with an inorganic water oxidation photocatalyst to promote overall water splitting without any sacrificial reagents. First, a promising combination of an organic catalyst, an inorganic catalyst, and a redox mediator was identified by using high-throughput screening of a library of components. A Z-scheme system composed of P10 (homopolymer of dibenzo[<i>b</i>,<i>d</i>]thiophene sulfone)-Fe<sup>2+</sup>/Fe<sup>3+</sup>-BiVO<sub>4</sub> was then constructed for overall water splitting under visible light irradiation. Transient absorption spectroscopy was used to assign timescales to the various steps in the photocatalytic process. While the overall solar-to-hydrogen efficiency of this first example is low, it provides proof of concept for other hybrid organic-inorganic Z-scheme architectures in the future.</p>


2020 ◽  
Author(s):  
Yang Bai ◽  
Keita Nakagawa ◽  
Alexander Cowan ◽  
Catherine Aitchison ◽  
Yuichi Yamaguchi ◽  
...  

<p>Linear conjugated polymers have potential as photocatalysts for hydrogen production from water but so far, most studies have involved non-scalable sacrificial reagents. Z-schemes comprising more than one semiconductor are a potential solution, but it is challenging to design these systems because multiple components must work together synergistically. Here, we show that a conjugated polymer photocatalyst for proton reduction can be coupled in a Z-scheme with an inorganic water oxidation photocatalyst to promote overall water splitting without any sacrificial reagents. First, a promising combination of an organic catalyst, an inorganic catalyst, and a redox mediator was identified by using high-throughput screening of a library of components. A Z-scheme system composed of P10 (homopolymer of dibenzo[<i>b</i>,<i>d</i>]thiophene sulfone)-Fe<sup>2+</sup>/Fe<sup>3+</sup>-BiVO<sub>4</sub> was then constructed for overall water splitting under visible light irradiation. Transient absorption spectroscopy was used to assign timescales to the various steps in the photocatalytic process. While the overall solar-to-hydrogen efficiency of this first example is low, it provides proof of concept for other hybrid organic-inorganic Z-scheme architectures in the future.</p>


2022 ◽  
Author(s):  
Yang Bai ◽  
Chao Li ◽  
Lunjie Liu ◽  
Yuichi Yamaguchi ◽  
Bahri Mounib ◽  
...  

The production of hydrogen from water via solar water splitting is a potential method to overcome the intermittency of the Sun’s energy by storing it as a chemical fuel. Inorganic semiconductors have been studied extensively as photocatalysts for overall water splitting, but polymer photocatalysts are also receiving growing attention. So far, most studies involving organic polymers report hydrogen production with sacrificial electron donors, which is unsuitable for large-scale hydrogen energy production. Here we show that a linear conjugated polymer photocatalyst can be used for overall water splitting to produce stoichiometric amounts of H2 and O2. We studied a range of different metal co-catalysts in conjunction with the linear polymer photocatalyst, the homopolymer of dibenzo[b,d]thiophene sulfone (P10). Photocatalytic activity was observed for palladium/iridium oxide-loaded P10, while other co-catalysts resulted in materials that showed no activity for overall water splitting. The reaction conditions were further optimized and the overall water splitting using the IrO2-loaded P10 was found to proceed steadily for an extended period (>60 hours) after the system stabilized. These results demonstrate that conjugated polymers can act as single component photocatalytic systems for overall water splitting when loaded with suitable co-catalysts, albeit currently with low activities. Significantly, though, organic polymers can be designed to absorb a large fraction of the visible spectrum, which can be challenging with inorganic catalysts. Transient spectroscopy shows that the IrO2 co-catalyst plays an important role in the generation of the charge separated state required for water splitting, with evidence for fast hole transfer to the co-catalyst. This solid-state approach should be transferable to other polymer photocatalysts, allowing this field to move away from sacrificial hydrogen production towards overall water splitting.


2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.


Nanoscale ◽  
2021 ◽  
Author(s):  
Dongxue Yao ◽  
Lingling Gu ◽  
Bin Zuo ◽  
Shuo Weng ◽  
Shengwei Deng ◽  
...  

The technology of electrolyzing water to prepare high-purity hydrogen is an important field in today's energy development. However, how to prepare efficient, stable, and inexpensive hydrogen production technology from electrolyzed...


Nanoscale ◽  
2021 ◽  
Author(s):  
Hu Liu ◽  
Mengqi Shen ◽  
Peng Zhou ◽  
Zhi Guo ◽  
Xinyang Liu ◽  
...  

Developing an efficient single component photocatalyst for overall water splitting under visible-light irradiation is extremely challenging. Herein, we report a metal-free graphitic carbon nitride (g-CxN4)-based nanosheet photocatalyst (x = 3.2,...


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