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dc.contributor.authorQureshi, Muhammad
dc.contributor.authorGarcia-Esparza, Angel T
dc.contributor.authorShinagawa, Tatsuya
dc.contributor.authorSautet, Philippe
dc.contributor.authorLe Bahers, Tangui
dc.contributor.authorTakanabe, Kazuhiro
dc.date.accessioned2018-12-31T13:16:24Z
dc.date.available2018-12-31T13:16:24Z
dc.date.issued2018
dc.identifier.citationQureshi M, Garcia-Esparza AT, Shinagawa T, Sautet P, Le Bahers T, et al. (2018) Contribution of electrolyte in nanoscale electrolysis of pure and buffered water by particulate photocatalysis. Sustainable Energy & Fuels 2: 2044–2052. Available: http://dx.doi.org/10.1039/c8se00272j.
dc.identifier.issn2398-4902
dc.identifier.doi10.1039/c8se00272j
dc.identifier.urihttp://hdl.handle.net/10754/630449
dc.description.abstractPhotocatalysis using semiconductor powders in suspension performs reduction and oxidation reactions at nanometer-scale distances. Such short distances between the reduction (cathode) and the oxidation (anode) sites enable photocatalytic water splitting to generate H2 and O2 from pure water without a supporting electrolyte, which is otherwise impossible in conventional electrode systems due to the high solution resistance. A CrOx/Pt/SrTiO3 model photocatalyst achieves high efficiency under UV irradiation in ultra-pure water splitting at rates (>1 μmol-H2 per cm2 per h) corresponding to electrocatalysis on the order of mA cm−2. The introduction of an unbuffered supporting electrolyte did not improve the photocatalytic rates, consistent with the negligible ohmic losses (<1 mV) numerically calculated using the Poisson–Nernst–Planck equations. The Nernstian potential loss resulting from pH gradients became apparent at high photocatalytic rates (>100 mV when rate >1 μmol-H2 per cm2 per h) even when the distance between redox sites was below 10 nm. Substantial improvements in photocatalytic rates were observed when buffer ions were introduced into near-neutral pH media by not only circumventing pH gradients but introducing kinetically facile H+ reduction to H2 instead of the kinetically sluggish direct reduction of H2O to H2. Herein, the quantitative descriptions of the electric potential, concentration gradients, and catalytic performance in nanoscale water electrolysis are presented with emphasis on (1) the advantages of performing redox reactions at the nanoscale, (2) the use of electrolyte engineering at near-neutral pH as a universal and effective strategy, and (3) the effectiveness of transferring knowledge from electrocatalysis to photocatalysis, where the potential is quantitatively defined regarding the former and poorly quantified regarding the latter.
dc.description.sponsorshipThe research reported in this publication was supported by King Abdullah University of Science and Technology (KAUST).
dc.publisherRoyal Society of Chemistry (RSC)
dc.relation.urlhttp://pubs.rsc.org/en/content/articlehtml/2018/se/c8se00272j
dc.titleContribution of electrolyte in nanoscale electrolysis of pure and buffered water by particulate photocatalysis
dc.typeArticle
dc.contributor.departmentCatalysis for Energy Conversion (CatEC)
dc.contributor.departmentChemical Science Program
dc.contributor.departmentKAUST Catalysis Center (KCC)
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalSustainable Energy & Fuels
dc.contributor.institutionUniv Lyon, ENS de Lyon, CNRS, Université Claude Bernard Lyon 1, Laboratoire de Chimie UMR 5182, F-69342 Lyon, France
dc.contributor.institutionDepartment of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, USA
dc.contributor.institutionDepartment of Chemical and Biomolecular Engineering, University of California Los Angeles (UCLA), Los Angeles, USA
kaust.personQureshi, Muhammad
kaust.personShinagawa, Tatsuya
kaust.personTakanabe, Kazuhiro


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