Photocatalytically Active Superstructures of Quantum Dots and Iron Porphyrins for Reduction of CO2 to CO in Water

Shichen Lian, Mohamad S. Kodaimati, Emily A Weiss

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

This paper describes the use of electrostatic assemblies of negatively charged colloidal CuInS2/ZnS quantum dot (QD) sensitizers and positively charged, trimethylamino-functionalized iron tetraphenylporphyrin catalysts (FeTMA) to photoreduce CO2 to CO in water upon illumination with 450 nm light. This system achieves a turnover number (TON) of CO (per FeTMA) of 450 after 30 h of illumination, with a selectivity of 99%. Its sensitization efficiency (TON per Joule of photons absorbed) is a factor of 11 larger than the previous record for photosensitization of an iron porphyrin catalyst for this reaction, held by a system in which both QDs and metal porphyrin were uncharged. Steady-state and time-resolved optical spectroscopy provides evidence for electrostatic assembly of QDs and FeTMA. Control of the size of the assemblies with addition of a screening counterion, K+, and a correlation between their measured size and their catalytic activity, indicates that the enhancement in performance of this system over the analogous uncharged system is due to the proximity of the FeTMA catalyst to multiple light-absorbing QDs and the selective formation of QD-FeTMA contacts (rather than QD-QD or FeTMA-FeTMA contacts). This system therefore shows the ability to funnel photoinduced electrons to a reaction center, which is crucial for carrying out reactions that require multistep redox processes under low photon flux, and thus is an important advance in developing artificial photocatalytic systems that function in natural light.

Original languageEnglish
Pages (from-to)568-575
Number of pages8
JournalACS Nano
Volume12
Issue number1
DOIs
Publication statusPublished - Jan 23 2018

Fingerprint

Porphyrins
Carbon Monoxide
porphyrins
Semiconductor quantum dots
Iron
quantum dots
iron
Water
catalysts
assemblies
water
Catalysts
Electrostatics
Photons
Lighting
illumination
electrostatics
funnels
photons
catalytic activity

Keywords

  • artificial photosynthesis
  • copper indium sulfide
  • electrostatic self-assembly
  • nanocrystals
  • photoredox catalysis

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Photocatalytically Active Superstructures of Quantum Dots and Iron Porphyrins for Reduction of CO2 to CO in Water. / Lian, Shichen; Kodaimati, Mohamad S.; Weiss, Emily A.

In: ACS Nano, Vol. 12, No. 1, 23.01.2018, p. 568-575.

Research output: Contribution to journalArticle

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