Article

Solar-driven reforming of lignocellulose to H2 with a CdS/CdOx photocatalyst

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Abstract

Lignocellulose is Earth’s most abundant form of biomass and its valorization to H2 is a key objective for the generation of renewable fuels. Solar-driven photocatalytic reforming of lignocellulose to H2 at ambient temperature offers a sustainable route towards this goal, but this reaction is currently limited to noble-metal-containing systems that operate with low activity under ultraviolet light. Here, we report the light-driven photoreforming of cellulose, hemicellulose and lignin to H2 using semiconducting cadmium sulfide quantum dots in alkaline aqueous solution. We show that basic conditions cause these dots to become coated with oxide/hydroxide in situ, presenting a strategy to improve their photocatalytic performance. The system operates under visible light, is stable beyond six days and is even able to reform unprocessed lignocellulose, such as wood and paper, under solar irradiation at room temperature, presenting an inexpensive route to drive aqueous proton reduction to H2 through waste biomass oxidation.

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Author information

Author notes

    • David W. Wakerley
    •  & Moritz F. Kuehnel

    These authors contributed equally to this work.

Affiliations

  1. Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK

    • David W. Wakerley
    • , Moritz F. Kuehnel
    • , Katherine L. Orchard
    • , Khoa H. Ly
    • , Timothy E. Rosser
    •  & Erwin Reisner

Authors

  1. Search for David W. Wakerley in:

  2. Search for Moritz F. Kuehnel in:

  3. Search for Katherine L. Orchard in:

  4. Search for Khoa H. Ly in:

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Contributions

D.W.W., M.F.K. and E.R. conceived the research. D.W.W. and M.F.K. performed photocatalysis and NMR experiments. D.W.W. and K.L.O. synthesized and characterized the QDs. K.L.O. executed TEM, XRD and the zeta potential analysis. K.H.L. carried out the Raman experiments. D.W.W. and T.E.R. carried out the fluorescence measurements. All authors analysed the data. D.W.W. wrote the manuscript. M.F.K., K.H.L. and E.R. added to the discussion and contributed to the preparation of the manuscript. E.R. supervised the work.

Competing interests

Patent applications covering this work have been filed by Cambridge Enterprise (UK patent application numbers GB1619953.1 and GB1701130.5) that name D.W.W., M.F.K., K.L.O. and E.R. as inventors.

Corresponding author

Correspondence to Erwin Reisner.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Tables 1–10, Supplementary Figures 1–14.

Videos

  1. 1.

    Supplementary Video 1

    Video of the reported system evolving H2 in the presence of a cutting from a wooden branch or paper. 3.6 nmol of ligand-free CdS QDs in DMF are injected onto each substrate and dried. The substrate was then added to 2 ml of 10 M KOH, forming CdS/CdOx. Samples were purged with N2 and irradiated using simulated solar light (AM 1.5G, 100 mW cm−2) for 1 h before filming. Filming was undertaken while irradiating with light from a nearby Kodak carousel 2020 projector.