Solution-processable polymers of intrinsic microporosity for gas-phase carbon dioxide photoreduction

Journal article

Carbon dioxide emissions from burning fossil fuels is one of the key underlying causes of global warming. The removal of carbon dioxide from the atmosphere, as well as the mitigation of the use of fossil fuels is of growing concern with carbon dioxide levels approaching non-reversible amounts, and addressing the issue is becoming imperative. Solar fuels offer an elegant solution and merit research and understanding. Solar fuels store solar energy in chemical bonds and offer a synthetic, carbon neutral and renewable alternative to fossil fuels. They directly address issues of the intermittency of solar energy and its transport and storage.Carbon dioxide photocatalysis also offers the possibility of a carbon negative process, via synthetic formation of chemicals such as methanol or higher hydrocarbons for use as feed-stock or solvents in chemical industries. This thesis focuses on the use of organic semiconductors for solar fuels applications. The processability of organic materials, tuneable energetics, and functionalities as well as their inexpensive starting supplies and scalability make them an ideal candidate as materials in the formation of solar fuels. This work initially focused on photoelectrochemical water splitting. Specifically, it was found that the presence of an organic overlayer with glycol chains and anchor groups showed an increase coverage of TiO2 ALD at low cycle numbers, and showed an increased stability compared to the same device with no overlayer. This study highlighted the potential of organic functionalities in addressing the issues of adhesion and stability in photocathodes. Principles from photoelectrochemistry were adapted when looking into photochemistry for carbon dioxide reduction. Firstly, a set up was designed, built, and optimised for gas phase photoreduction of carbon dioxide. In conjunction a series of conjugated, solution processable polymers of intrinsic microporosity were designed and adjusted for use as materials catalysing carbon dioxide photoreduction in the presence of hydrogen. The structure-performance relationship was interpreted, and it was found that increasing pore sizes and higher photoluminescence decay times were related to increased CO production. The polymers were also tested as heterojunctions and with the presence of a copper-based co-catalyst which enhanced activity significantly. Learning from the design of this iptycene based series, another series based on spirobifluorene compounds, with higher yields and fewer synthetic steps was designed to further investigate pore sizes and taking advantage of the structure's known fluorescent properties. These studies paved the way for solution processable polymers for this application. This work outlines the interdisciplinary nature of photocatalysis and emphasizes the multitude of factors to be reconsidered in this application, in an attempt to lead to intelligent material and testing desig

Authors: Moruzzi, F; Zhang, W; Purushothaman, B; Gonzalez-Carrero, S; Aitchison, CM

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Nature Communications
• Volume: 14
• Issue: 1
• Pages: 3443-3443
• Publication date: 2023-06-10
• DOI: 10.1038/s41467-023-39161-6
• EISSN: 2041-1723
• ISSN: 2041-1723
• Language: English
• Keywords: Organic chemistry; Copper; Catalysis; Phase (matter); Chemical engineering; Materials science; Composite material; Carbon dioxide; Carbon monoxide; Polymer chemistry; Porosity; Chemistry; Polymer