Triple-Channel Charge Transfer over W18O49/Au/g‑C3N4 Z‑Scheme Photocatalysts for Achieving Broad-Spectrum Solar Hydrogen Production
journal contributionposted on 2021-11-01, 15:06 authored by Inju Hong, Yi-An Chen, Yung-Jung Hsu, Kijung Yong
Z-scheme heterojunctions are fundamentally promising yet practically appealing for photocatalytic hydrogen (H2) production owing to the enhanced redox power, spatial separation of charge carriers, and broad-spectrum solar light harvesting. The charge-transfer dynamics at Z-scheme heterojunctions can be accelerated by inserting charge-transfer mediators at the heterojunction interfaces. In this study, we introduce Au nanoparticle mediators in the Z-scheme W18O49/g-C3N4 heterostructure, which enables an improved H2 production rate of 3465 μmol/g·h compared with the direct Z-scheme W18O49/g-C3N4 (1785 μmol/g·h) under 1 sun irradiation. The apparent quantum yields of H2 production with W18O49/Au/g-C3N4 are 3.9% and 9.3% at 420 and 1200 nm, respectively. The improved photocatalytic H2 production activity of W18O49/Au/g-C3N4 is attributable to the triple-channel charge-transfer mechanism: channel IZ-scheme charge transfer facilitates charge separation and increased redox power of the photoexcited electrons; channels II and IIIthe localized surface plasmon resonances from Au (channel II) and W18O49 (channel III) enable light harvesting extension from visible to near-infrared wavelengths.
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increased redox powerenhanced redox powerapparent quantum yields>‑ scheme photocatalysts>- scheme heterojunctions1 sun irradiation49 </ sub4 </ sub2 </ sub18 </ sub>- scheme wg · h3 </ subg ‑ cimproved photocatalytic hchannel charge transferz </improved hphotocatalytic hydrogentransfer mediatorstransfer mechanismtransfer dynamicsspatial separationphotoexcited electronsinserting chargeinfrared wavelengthsiii heterojunction interfacescharge carrierschannels iichannel iiichannel iichannel charge3465 μmol1785 μmol1200 nm