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Making Graphene Holey. Gold-Nanoparticle-Mediated Hydroxyl Radical Attack on Reduced Graphene Oxide


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Here graduate student James Radich gives a brief overview of the concept, synthesis, and implications of Holey Graphene.

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Making Graphene Holey. Gold-Nanoparticle-Mediated Hydroxyl Radical Attack on Reduced Graphene Oxide

  1. 1. Motivation•Develop solution-based synthesis for porous graphenemorphology, i.e. Holey Graphene or oxidized reduced grapheneoxide (ORGO)•Utilize gold nanoparticles (AuNP) as catalytic “nanodrills” togenerate holes in graphene sheets•Elucidate fundamental interactions between ReducedGraphene Oxide (RGO) and hydroxyl radicals•Exert morphological control via reaction modulation
  2. 2. Synthesis•UV-Peroxide system for OH radical production•AuNP for their superior catalytic oxidation properties•Decreases in UV-visible absorption panel D depict the oxidation of RGOto generate holes as evident in TEM image D. (Irradiated 2 hours)
  3. 3. Confirming the Oxidation•In Figure: (a) Au-H2O2-RGO, (b) H2O2-RGO, (c) RGO•FTIR spectra indicate C=C attack via OH radicals•Without AuNP ORGO is characterized by direct –OH addition to the RGO•AuNP alleviate buildup of –OH functionalities and further catalyze theoxidation
  4. 4. Effect of AuNP on H2O2 Photolysis•Fluorescence intensity proportional to OH radical production•Plot A shows 1.3x increase in OH radicals with AuNP•Plot B depicts effect of OH radical production with incrementalincreases in AuNP
  5. 5. Probing the Reaction Mechanism•Nanosecond laser flash photolysis was used with competition kinetics tofurther probe the reaction mechanism and to ascertain rate constants ofOH radical attack on RGO with and without AuNP•kRGO = 4.4 x 109•kAu-RGO = 1.2 x 1010
  6. 6. Proposed Reaction Mechanism
  7. 7. Reaction Modulation•Photon-filtering reduces flux ofphotons available forphotodecomposition of H2O2 to OHradicals•Tunable reaction and morphology
  8. 8. Conclusions and Perspectives•A new graphene morphology, Holey Graphene, was developedusing AuNP and RGO in a solution-based synthetic scheme•AuNP catalyze both UV photolysis of H2O2 and OH radicalattack on RGO•Through modulation of photon flux the final ORGOmorphology can be tuned•Significant issues are raised with regard to stability ofgraphene in the presence of noble metal catalyst and oxidativeradicals (i.e. photocatalysis, fuel cells, lithium-air batteries)
  9. 9. Thank YouDOI: 10.1021/nn401794k