Promotion of atomic hydrogen recombination as an alternative to electron trapping for the role of metals in the photocatalytic production of H2.
The production of hydrogen from water with semiconductor photocatalysts can be promoted by adding small amounts of metals to their surfaces. The resulting enhancement in photocatalytic activity is commonly attributed to a fast transfer of the excited electrons generated by photon absorption from the semiconductor to the metal, a step that prevents deexcitation back to the ground electronic state. Here we provide experimental evidence that suggests an alternative pathway that does not involve electron transfer to the metal but requires it to act as a catalyst for the recombination of the hydrogen atoms made via the reduction of protons on the surface of the semiconductor instead.
Department of Chemistry, University of California, Riverside, CA 92521.
Ji Bong
JB
Joo
Department of Chemistry, University of California, Riverside, CA 92521.
Robert
R
Dillon
Department of Chemistry, University of California, Riverside, CA 92521.
Ilkeun
I
Lee
Department of Chemistry, University of California, Riverside, CA 92521.
Yadong
Y
Yin
Department of Chemistry, University of California, Riverside, CA 92521.
Christopher J
CJ
Bardeen
Department of Chemistry, University of California, Riverside, CA 92521 zaera@ucr.edu.
Francisco
F
Zaera
D002384:Catalysis; D003722:Dental Alloys / Q000737:chemistry*; D004583:Electrons; D005453:Fluorescence; D006859:Hydrogen / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry; D010777:Photochemistry / Q000379:methods*; D012666:Semiconductors; D012993:Solar Energy
D003722:Dental Alloys; D008670:Metals; C416206:gold-titanium alloy; D006859:Hydrogen
core-shell nanostructures; gold–titania; hydrogen production; photocatalysis; time-resolved fluorescence