Rapid fabrication of KTa0.75Nb0.25/g-C3N4 composite via microwave heating for efficient photocatalytic H2 evolution. (1st April 2019)

• Record Type: Journal Article
• Authors: Chen, Zhiqiang; Chen, Pengfei; Xing, Pingxing; Hu, Xin; Lin, Hongjun; Zhao, Leihong; Wu, Ying; He, Yiming
• Is Part Of: Fuel. Volume 241(2019)
• Page Start: 1
• Page End: 11
• Publication Date: 2019-04-01
• Subjects: KTa0.75Nb0.25O3 -- g-C3N4 -- Photocatalytic H2 evolution -- Microwave heating method; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.12.011
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: KTa0.75 N0.25 O3 (KTN)/g-C3 N4 was synthesized in 35 min via microwave heating. KTN/g-C3 N4 presented excellent performance in H2 evolution under simulated sunlight and visible light. The H2 -evolution rate of KTN/g-C3 N4 was 9.3 times faster than g-C3 N4 under visible light. The high photoactivity of KTN/g-C3 N4 was ascribed to the improved charge separation. Abstract: A novel KTa0.75 Nb0.25 O3 (KTN)/g-C3 N4 composite photocatalyst was fabricated through microwave heating for realizing the efficient photocatalytic H2 evolution. The energy-efficient preparation method allowed g-C3 N4 to be formed in-situ on KTN surface in thirty five minutes. The binary constitution of the KTN/g-C3 N4 composite was verified by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) experiments. UV–visible diffuse reflection spectroscopy (DRS) experiments suggested that the photoabsorption performance was increased after the introduction of KTN. N2 -adsorption analysis indicated that the addition of KTN slightly increased the surface area of g-C3 N4 . Photoluminescence (PL) spectroscopy, electrochemical impedance spectroscopy (EIS) and transient photocurrent response (PC) analyses confirmed that the KTN/g-C3 N4 composite displayed longer lifetime of photoexcited charge carriers than g-C3 N4, owing to the suitable band potentials and the close contact of KTN and g-C3 N4 . This property was believed to the key characteristic of the composite, which led to its excellent photocatalytic performance. Under simulated sunlight irradiation, the optimal KTN/g-C3 N4 catalyst presented a photocatalytic H2 -generation rate of 1673 μmol·g −1 ·h −1, 2.5 and 2.4 times higher than that of KTN and pure g-C3 N4, respectively. Under visible light irradiation, the value was determined to be 86.2 μmol·g −1 ·h −1, which achieved 9.3 times that of g-C3 N4 .