Oral Presentation Royal Australian Chemical Institute National Congress 2026

MOF templated synthesis of homogeneously doped SrTiO3:La/Rh (136478)

Thomas J O'Dea 1 , Christopher J Sumby 1 , Gregory F Metha 1 , Cameron J Shearer 1
  1. School of Physics, Chemistry and Earth Sciences, Adelaide University, Adelaide, South Australia, Australia

Hydrogen is positioned as a high value chemical with vast applications in the green energy transition.1-3 For this reason, the ability to produce hydrogen renewably is of significant interest.1-3 Solar driven photocatalytic water splitting is a promising technology in this regard as it would allow for clean hydrogen production using water, sunlight and a photocatalytic substrate.1-3 Traditional materials only absorb at most ~4% of energy we receive from the Sun, so efficient visible light sensitive materials are key.3 Heteroatom doping has been shown as a useful strategy in improving the visible light response of the most efficient photocatalysts.3 Traditional doping strategies result in inhomogeneity introducing defects and limiting activity.3 Herein are presented synthetic approaches to produce a homogeneously doped material with enhanced visible light absorbance. A metal-organic framework, or MOF, containing titanium and strontium is used as a template to house dopants prior to thermal conversion to yield a crystalline homogeneously doped metal oxide – SrTiO3:La/Rh – as shown through high resolution STEM-EDS mapping. Not only is the dopant distribution improved but the increased dopant concentration results in enhanced visible light absorbance and a reduction in bandgap to 2.45 eV from 2.70 eV.3 As such, MOF derived materials show a proportionally greater visible light response than conventionally synthesized materials as well as evolving hydrogen deeper into the visible spectrum than typically observed. Synchrotron PD has revealed differences in crystal structure between MOF derived and conventional materials that may explain differences in photocatalytic activity. Exploration of additional doping schemes has shown this approach to be generalizable across systems. Recent work has identified a related new doping approach that appears to further improve visible light absorbance over what was previously demonstrated.

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  2. (2) Shearer, C. J.; Hisatomi, T.; Domen, K.; Metha, G. F. Gas phase photocatalytic water splitting of moisture in ambient air: Toward reagent-free hydrogen production. Journal of Photochemistry and Photobiology A: Chemistry 2020, 401, 112757.
  3. (3) Small, T. D.; Hamza, M. A.; Shen, Y.; Shearer, C. J.; Metha, G. F. Systematic investigation of ABO 3 perovskite synthesis to generalise a La and Rh co-doping strategy for visible light photocatalysis. Nanoscale Advances 2025.