Novel carbon modified KTa0.75Nb0.25O3 nanocubes with excellent efficiency in photocatalytic H2 evolution. (1st December 2018)

• Record Type: Journal Article
• Authors: Chen, Zhiqiang; Chen, Pengfei; Xing, Pingxing; Hu, Xin; Lin, Hongjun; Wu, Ying; Zhao, Leihong; He, Yiming
• Is Part Of: Fuel. Volume 233(2018)
• Page Start: 486
• Page End: 496
• Publication Date: 2018-12-01
• Subjects: Photocatalysis -- KTa1−xNbxO3 -- Solid solution -- Carbon nanomaterials -- Photocatalytic hydrogen evolution; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.06.090
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: C/KTa0.75 Nb0.25 O3 composite was synthesized for the first time. C/KTa0.75 Nb0.25 O3 exhibited excellent efficiency in H2 generation and RhB degradation. The H2 -productionate of C/KTa0.75 Nb0.25 O3 is 9.4 times faster than that of KTaO3 . The origin of the high performance was discussed. Abstract: This work was designed to synthesize an efficient photocatalyst for photocatalytic H2 evolution via the decoration of carbon on an optimal KTa1−x Nbx O3 solid solution. The C/KTa1−x Nbx O3 composite was fabricated via a two-step hydrothermal process, and investigated by various techniques, including N2 adsorption, X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), transmission electron microscopy(TEM), X-ray photoelectron spectroscopy (XPS), UV − vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), transient photocurrent response (PC) an electrochemical impedance spectroscopy (EIS). The catalytic performance of the composite was investigated via photocatalytic H2 evolution and rhodamine B (RhB) degradation under irradiation of simulated sunlight. Results indicate that the formation of KTa1−x Nbx O3 solid solution improves the bulk charge separation, and consequently leads to the high photocatalytic activity. KTa0.75 Nb0.25 O3 solid solution presents the fastest rate for H2 evolution. The loading of a thin carbon layer on the KTa0.75 Nb0.25 O3 nanocube can further fasten the process. The optimal composite sample displays a H2 evolution rate of 1776 μmol·g −1 ·h −1, which is 2.44 and 9.40 times that of KTa0.75 Nb0.25 O3 and KTaO3, respectively. The load carbon thin layer enhances the surface area and hinders the surface charge recombination via trapping the electrons, which is believed to be the main reason for the excellent performance. Additionally, the synthesized C/KTa0.75 Nb0.25 O3 composite also presents good photoactivity in RhB degradation. This work affords a practical approach for the design and preparation of highly efficient photocatalysts via bulk doping and surface modification simultaneously.