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Optical control of selectivity of high rate CO₂ photoreduction via interband- or hot electron Z-scheme reaction pathways in Au-TiO₂ plasmonic photonic crystal photocatalyst

From National Research Council Canada

Alternative titleOptical control of selectivity of high rate CO2 photoreduction via interband- or hot electron Z-scheme reaction pathways in Au-TiO2 plasmonic photonic crystal photocatalyst
DOIResolve DOI: https://doi.org/10.1016/j.apcatb.2020.118644
AuthorSearch for: ; Search for: ; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0001-9238-1418; Search for: ORCID identifier: https://orcid.org/0000-0003-2456-396X; Search for: ; Search for: ; Search for: ; Search for: ORCID identifier: https://orcid.org/0000-0002-5107-6086; Search for: 1; Search for: 1; Search for: ORCID identifier: https://orcid.org/0000-0003-2804-9298; Search for: ORCID identifier: https://orcid.org/0000-0001-7347-3333
Affiliation
  1. National Research Council of Canada. Nanotechnology
FormatText, Article
Subjectheterogeneous catalysis; light trapping; plasmonic photocatalysis; density functional theory; FDTD simulations
Abstract
Photonic crystals consisting of TiO₂ nanotube arrays (PMTiNTs) with periodically modulated diameters were fabricated using a precise charge-controlled pulsed anodization technique. The PMTiNTs were decorated with gold nanoparticles (Au NPs) to form plasmonic photonic crystal photocatalysts (Au-PMTiNTs). A systematic study of CO₂ photoreduction performance on as-prepared samples was conducted using different wavelengths and illumination sequences. A remarkable selectivity of the mechanism of CO₂ photoreduction could be engineered by merely varying the spectral composition of the illumination sequence. Under AM1.5 G simulated sunlight (pathway#1), the Au-PMTiNTs produced methane (302 μmol gcat.⁻¹ h⁻¹) from CO2 with high selectivity (89.3 %). When also illuminated by a UV-poor white lamp (pathway#2), the Au-PMTiNTs produced formaldehyde (420 μmol gcat.⁻¹ h⁻¹) and carbon monoxide (323 μmol gcat.⁻¹ h⁻¹) with almost no methane evolved. We confirmed the photoreduction results by 13C isotope labeling experiments using GC[sbnd]MS. These results point to optical control of the selectivity of high-rate CO2 photoreduction through selection of one of two different mechanistic pathways. Pathway#1 implicates electron-hole pairs generated through interband transitions in TiO₂ and Au as the primary active species responsible for reducing CO₂ to methane. Pathway#2 involves excitation of both TiO₂ and surface plasmons in Au. Hot electrons produced by plasmon damping and photogenerated holes in TiO₂ proceed to reduce CO₂ to HCHO and CO through a plasmonic Z-scheme.
Publication date
PublisherElsevier
In
  • Applied Catalysis B: Environmental 267, 118644.
LanguageEnglish
Peer reviewedYes
IdentifierS092633732030059X
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Record identifier605e383c-5925-4edf-8814-2764938ff200
Record created2020-06-29
Record modified2020-06-29
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