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Mechanistic Insight into the Interaction Between a Titanium Dioxide Photocatalyst and Pd Cocatalyst for Improved Photocatalytic Performance

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DOI

  • Ren Su, Synfuels China Company Ltd., Huairou district, Beijing 101400, China
  • ,
  • Nikolaos Dimitratos, Cardiff University, United Kingdom
  • Jinjia Liu, Synfuels China Company Ltd., Huairou district, Beijing 101400, China, China
  • Emma Carter, Cardiff University, United Kingdom
  • Sultan Althahban, Lehigh University, United States
  • Xueqin Wang
  • ,
  • Yanbin Shen, Synfuels China Company Ltd., Huairou district, Beijing 101400, China
  • ,
  • Stefan Wendt
  • ,
  • Xiaodong Wen, Synfuels China Company Ltd., Huairou district, Beijing 101400, China, China
  • J.W. (Hans) Niemantsverdriet, Synfuels China Company Ltd., Huairou district, Beijing 101400, China, China
  • Bo Brummerstedt Iversen
  • Christopher Kiely, Lehigh University, United States
  • Graham J. Hutchings, Cardiff University, United Kingdom
  • Flemming Besenbacher

Understanding the cocatalyst/semiconductor interaction is of key importance for the design and synthesis of next generation photocatalytic materials for efficient hydrogen production and environmental cleanup applications. Here we investigate preformed Pd nanoparticles (NPs) supported on a series of anatase TiO 2 having well-controlled but varying degrees of crystallinity and crystallite size, and explore their photocatalytic performance for H 2 production and phenol decomposition. While tuning the anatase crystallite size significantly influences the photocatalytic performance, varying the TiO 2 crystallinity shows a negligible effect. Interestingly, the optimum quantum efficiency (∼78%) for H 2 evolution is achieved with anatase having medium crystallite size (∼16 nm), whereas for phenol decomposition, a promotional effect is only observed for anatase with larger crystallite sizes (>20 nm). Surface radical species and radical densities study reveal that the photogenerated charge carriers have been trapped at different sites depending on the crystallite size of anatase. While the excited electrons are only trapped in bulk lattice sites in small anatase (<16 nm), larger anatase particles provide extra surface sites for charge trapping, which benefit charge storage and transportation to Pd surface sites, leading to a more efficient utilization of charge carriers for photocatalysis. Additionally, Pd supported on medium sized anatase (∼16 nm) hinders the formation of O 2 •- radicals on TiO 2 surfaces, thus preventing unwanted reoxidation of photogenerated H 2.

Original languageEnglish
JournalACS Catalysis
Volume6
Issue7
Pages (from-to)4239-4247
Number of pages9
ISSN2155-5435
DOIs
Publication statusPublished - 2016

    Research areas

  • TiO, density functional theory, electron spin resonance, hydrogen evolution, metal-semiconductor interaction, phenol decomposition, photocatalysis

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