Solar-driven catalytic processes for sustainable fuels and chemicals production

Solar-driven catalytic conversion of CO2 emissions and chemical wastes into value-added fuels and chemicals offers a promising solution to address the escalating energy demand and promote sustainable development. However, the advancement of solar fuels technology is severely impeded by the challenges in terms of the insufficient catalytic performance, low overall system efficiency and high costs with current catalytic systems. This thesis commences with a fundamental investigation into the dynamic evolution of active sites and the intricate reaction mechanism of electrochemical CO2 reduction reaction (EC CO2RR). In this section, Cu2O microcrystals with controllable low- and high-index facets exposure are fabricated as archetypal catalysts to differentiate the effects of initial exposed facets on structural transformations and product selectivity. The Cu2O catalysts are further integrated with photovoltaic (PV) modules, which delivers a higher solar-to-fuels efficiency than that of natural photosynthesis. In the second part, a series of Zn/In catalysts have been developed for CO2RR to selectively produce a single valuable liquid product. The optimal catalyst exhibits significant selectivity towards formate. In-situ characterizations reveal the catalyst undergoes a dynamic transformation that facilitate the production of formate by modulating the key intermediates adsorption. Moreover, by assembling the catalyst in a flow cell and integrating with a PV panel, a PV-EC system with high current density and solar-to-formate efficiency has been achieved. In the third part, to further improve the integrity of the solar-driven system, a universal concept is presented to design highly efficient photoelectrodes by constructing nano-structured top layer on commercial PV products. The designed photocathode shows the best reported photoelectrochemical (PEC) nitrate-to-NH3 performance. Also, we demonstrate a large-scale stand-alone PEC device that can simultaneously attain unbiased ammonia production and biomass oxidation. Its scalability and practical feasibility have been validated in outdoor testing with an assembled tandem device array. Techno-economic analysis confirms the compelling economic viability of the developed system. Overall, this thesis has achieved significant progress in solar-to-sustainable chemicals/fuels technology, demonstrating new understandings of catalysis, boosted performance, efficiency, and integrity, and diversified product categories.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2024

Author dc:creator

• Han, Chen

• CO2 reduction reaction
• Photoelectrocatalysis
• Ammonia production
• Electrocatalysis
• In-situ characterization
• Catalysts
• anzsrc-for: 4004 Chemical engineering
• anzsrc-for: 34 CHEMICAL SCIENCES

Statement dc:rights

• open access
• CC BY 4.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by/4.0/

Identifier

https://doi.org/10.26190/unsworks/30377

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/102732