Abstract
TiO2/hectorite composite photocatalysts with different molar ratios of lithium, magnesium, and silicon were synthesized by a one-pot hydrothermal method. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption isotherms, and ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS). When the molar ratio of lithium, magnesium, and silicon was 1.32:5.34:8 (TH-2), the composite showed the highest UV photocatalytic degradation of methylene blue (MB). The apparent rate constant of TH-2 was 0.04361 min−1, which was about 3.12 times that of EVONIK Degussa commercial TiO2 of AEROXIDE P25. The improvement of photocatalytic efficiency of the composite was mainly due to its high specific surface area, light trapping ability, and effective separation of electrons (e−) and holes (h+). At the same time, the F element of hectorite is beneficial to the formation of Ti3+ in TiO2, thus enhancing the photocatalytic activity. After five cycles, the removal rate of MB with TH-2 still reached 87.9%, indicating its excellent reusability.
Highlights
The development of the chemical industry has resulted in large-scale pollutant emission, which has brought about a series of environmental problems [1]
TiO2 was introduced into the interlayer of hectorite by the one-pot hydrothermal method and the synthesized TiO2/hectorite composites exhibited a higher UV photocatalytic activity than commercial P25
The number of titanium ions entering into the hectorite layer was changed by adjusting the molar ratio of lithium and magnesium in the raw material
Summary
The development of the chemical industry has resulted in large-scale pollutant emission, which has brought about a series of environmental problems [1]. In particular, are highly toxic and chemically stable, potentially teratogenic, and carcinogenic to humans [2]. As a “green” technology, photocatalysis has attracted widespread attention because it can efficiently degrade dyes to avoid its pollution to the environment [3,4]. Titanium dioxide (TiO2) is considered one of the most promising photocatalysts because of its advantages of good chemical stability, nontoxicity, and low cost to degrade organic pollutants in the field of printing and dyeing [5,6]. TiO2 has a wide band gap (3.0–3.2 eV) and excitation light is limited to ultraviolet light (4%), which greatly decreases its utilization efficiency of solar energy [7]. TiO2 nanoparticles exhibit a low specific surface area, easy aggregation, and poor recycling, which limit its application range [8]. Improving the adsorption capacity and photocatalytic performance of TiO2 is important
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