Mechanistic insights into N-hydroxyphthalimide modified graphitic carbon nitride boosted photocatalytic hydrogen production. Issue 19 (13th September 2019)

• Record Type: Journal Article
• Authors: Ma, Liu-Bo; Liang, Kuang; Wang, Gang; Fang, Xiao-Xiang; Ling, Cong; Zhao, Tan; Kombo, Miza; Cheang, Tuck-Yun; Xu, An-Wu
• Is Part Of: Catalysis science & technology. Volume 9:Issue 19(2019)
• Page Start: 5441
• Page End: 5446
• Publication Date: 2019-09-13
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c9cy01340g
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : N -Hydroxyphthalimide (NHPI) retards the recombination of electron–hole pairs through extracting holes from g-C3 N4, dramatically improving photocatalytic hydrogen production. Abstract : Graphitic carbon nitride (g-C3 N4 ) is considered as an attractive and appropriate material to split water and produce hydrogen (H2 ) under visible light. Nevertheless, the H2 evolution rate of g-C3 N4 is low due to the rapid recombination of electron–hole pairs. In this context, we develop a novel g-C3 N4 system combined with N -hydroxyphthalimide (denoted as NHPI) through π–π interactions and hydrogen bonds at the interface for circumventing this issue. NHPI conjugated small molecules act as an efficient hole mediator to reduce the recombination of electron–hole pairs and enhance the photocatalytic activity of g-C3 N4 . Under visible light excitation, the redox couple NHPI/NHPI + serves as a redox shuttle, which can facilitate the transfer of holes from g-C3 N4 to triethanolamine (TEOA), and the electrons can be shuttled to a Pt cocatalyst. Time-resolved photoluminescence (TRPL), photoelectrochemical (PEC) and electron paramagnetic resonance (EPR) measurements exhibit that the introduction of NHPI on g-C3 N4 boosts the visible-light photocatalytic activity through accelerating spatial separation of the electron–hole pairs. Upon introducing optimal 2 wt% NHPI, the photocatalytic H2 production rate of the g-C3 N4 /2 wt% NHPI (CN/2 wt% NHPI) composite is significantly enhanced up to 1145.4 μmol h −1 g −1, exceeding that of pristine g-C3 N4 (274.0 μmol h −1 g −1 ) by 4.2 times. Moreover, the reusability test shows that no obvious loss of activity is observed over the CN/2 wt% NHPI sample. Overall, an excellent stable and highly efficient photocatalyst of the CN/NHPI heterostructure has been obtained, which could find potential application in solar-to-fuel conversion.