Alkynyl carbon functionalized N-TiO2: Ball milling synthesis and investigation of improved photocatalytic activity

Abstract

Herein, a series of alkynyl carbon functionalized N-TiO2 is fabricated by ball milling of CaC2 and pre-prepared N-TiO2. Based on the X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy techniques, it is confirmed that the alkynyl carbon materials are successfully doped into N-TiO2. The visible light catalytic performance of the alkynylated N-TiO2 (CNT-0.1) for degradation of Rhodamine B, methylene blue, levofloxacin, and p-nitrophenol is higher than that of the N-TiO2. Further, the photocatalytic NH3 production over the alkynylated N-TiO2 is 83.11 μmol·h−1·g−1 in the presence of CH3OH as the proton source, which is 2.41 folds higher than that of the N-TiO2 under UV-Visible light irradiation. The dominant active species for the photodegradation of Rhodamine B are determined to be h+ and O2·- radicals. The photocatalytic stability is verified by the recyclable tests, demonstrating a little decrease in the Rhodamine B photodegradation performance. It can be concluded from the photo-current, photo-voltage, electrochemical impedance spectroscopy, photoluminescence spectra, UV–vis absorption spectra, and Mott-Schottky plots that modification of alkynyl carbon materials can decrease charge recombination and improve the visible light response capacity of the photocatalyst, finally resulting in the enhanced photocatalytic performance. This work illustrates that the introduction of alkynyl carbon into semiconductor materials is a very promising modification strategy for promoting their photocatalytic properties.