Modifying layered perovskite oxide for photocatalysis

Thesis

Perovskite has emerged as a noteworthy role in photocatalysis, demonstrating exceptional performance in water splitting, CO₂ reduction and organic pollutant degradation. Their intrinsic advantages, including tuneable band structures, high defect tolerance, and rich surface redox chemistry, position them as prime candidates for advancing photocatalytic reaction. Nevertheless, the full potential of perovskite-based systems remains underexplored, necessitating more investigations and modifications to understand its aptitude.

This thesis constructs an integrated ammonia energy cycle mediated by perovskite photocatalysts, delineating a closed-loop hydrogen economy encompassing three strategically linked phases: photocatalytic hydrogen generation from water splitting; photocatalytic ammonia synthesis for hydrogen storage and transportation; and on- demand hydrogen release through photocatalytic ammonia decomposition. Throughout this value chain, perovskite-based catalysts serve as the unifying platform, enabling an efficient interconversion between hydrogen and ammonia energy carriers.

The synthesised photocatalysts were characterised by Synchrotron X-ray diffraction, neutron powder diffraction, X-ray absorption spectroscopy, and X-ray pair distribution function. Subsequent contents correlate these structural insights with photochemical performance metrics, revealing mechanistic connections between crystallographic features and catalytic functionality.

Chapter 1 introduces the fundamental principles of layered perovskite materials along of various photocatalytic reactions. Chapter 2 outlines the experimental methodology, including catalyst characterisation techniques and catalytic activity evaluation V protocols. Chapter 3 investigates perovskite / reduced graphene oxide heterostructures for photocatalytic water splitting, with emphasis on interfacial charge transfer mechanisms. Chapter 4 elucidates the hydrazine-mediated photo-thermal decomposition of ammonia using protonated layered perovskites. Chapter 5 explores moiré-engineered 2D perovskite for enhanced ammonia synthesis efficiency.

Authors: Zhang, H

• DOI: 10.5287/ora-9egbjjr7v
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: perovskite; neutron diffraction; heterogeneous catalysis; synthesis and characterisation; synchrotron radiation
• Subjects: Inorganic chemistry; Catalysis; Materials science