A Visible‐Light‐Active Heterojunction with Enhanced Photocatalytic Hydrogen Generation. Issue 14 (10th June 2016)

• Record Type: Journal Article
• Authors: Adhikari, Shiba P.; Hood, Zachary D.; More, Karren L.; Chen, Vincent W.; Lachgar, Abdou
• Is Part Of: ChemSusChem. Volume 9:Issue 14(2016:Jul.)
• Page Start: 1869
• Page End: 1879
• Publication Date: 2016-06-10
• Subjects: composite -- heterojunction -- hydrogen production -- photocatalyst -- water splitting; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201600424
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: A visible‐light‐active carbon nitride (CN)/strontium pyroniobate (SNO) heterojunction photocatalyst was fabricated by deposition of CN over hydrothermally synthesized SNO nanoplates by a simple thermal decomposition process. The microscopic study revealed that nanosheets of CN were anchored to the surface of SNO resulting in an intimate contact between the two semiconductors. Diffuse reflectance UV/Vis spectra show that the resulting CN/SNO heterojunction possesses intense absorption in the visible region. The structural and spectral properties endowed the CN/SNO heterojunction with remarkably enhanced photocatalytic activity. Specifically, the photocatalytic hydrogen evolution rate per mole of CN was found to be 11 times higher for the CN/SNO composite compared to pristine CN. The results clearly show that the composite photocatalyst not only extends the light absorption range of SNO but also restricts photogenerated charge‐carrier recombination, resulting in significant enhancement in photocatalytic activity compared to pristine CN. The relative band positions of the composite allow the photogenerated electrons in the conduction band of CN to migrate to that of SNO. This kind of charge migration and separation leads to the reduction in the overall recombination rate of photogenerated charge carriers, which is regarded as one of the key factors for the enhanced activity. A plausible mechanism for the enhanced photocatalytic activity of the heterostructured composite is proposed based on observed activity, photoluminescence, time‐resolved fluorescence emission decay, electrochemical impedance spectroscopy, and band position calculations. Abstract : I can see the light ! A visible‐light‐active carbon nitride/strontium pyroniobate heterojunction was fabricated and evaluated for its photocatalytic reduction of water to hydrogen under visible light irradiation. The heterojunction photocatalyst extends the light absorption range and restricts photogenerated charge‐carrier recombination, resulting in enhanced photocatalytic activity compared to carbon nitride.