Abstract

A simple microwave method was employed to prepare silica-doped mesoporous zirconia nanoparticles, SiO₂/ZrO₂ (SiZr) catalysts under various Si amount and then characterized by X-ray diffraction, nitrogen adsorption–desorption analyses, Fourier-transform infrared, electron spin resonance, ultraviolet–visible diffuse reflectance spectroscopy and photoluminescence analyses. The lower amount of Si fully stabilized the ZrO₂ in the tetragonal phase (t-ZrO₂), but the higher amount of Si occupied oxygen vacancies (OV) in the SiZr lattice to disrupt the catalysts with introduce low content of monoclinic phase. The catalyst activity towards on photodegradation of 2-chlorophenol (2-CP) was ranked in the following order: 1SiZr (92%) > TiO₂ (73%) > 2SiZr (67%) > 3SiZr (64%) > 4SiZr (56%) > ZrO₂ (51%). This result demonstrated that 1SiZr gave the highest degradation percentage of 10 mg L⁻¹ 2-CP at pH 5 using 0.375 g L⁻¹ catalyst under visible light irradation within 4 h. The highest photoactivity of 1SiZr is due to the larger surface area and crystallite size, which resulted in a good surface contact with light and thus accelerated the photocatalytic activity. Additionally, the highest amount of OV possesed by 1 SiZr effectively suppressed the electron–hole recombination by acting as an electron acceptors, which consequently affected the t-ZrO₂ stabilization as well as the catalytic activity. The kinetics of photocatalytic degradation of 2-CP correlated with pseudo-first order model, with the surface reaction as the controlling step. The photogenerated hole was the most active species as confirmed by effect of scavenger study. The 1SiZr maintained the photocatalytic activities after five runs and has a great capability in degrading of various phenols derivatives, indicating its potential use in the phenol-based wastewater treatment.

Graphic Abstract

中文翻译：

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在稳定氧化锆的四方相中量身定制二氧化硅量以增强2-氯苯酚的光降解

摘要

采用简单的微波方法制备了掺杂硅的介孔氧化锆纳米粒子，各种Si含量的SiO ₂ / ZrO ₂（SiZr）催化剂，然后通过X射线衍射，氮吸附-解吸分析，傅立叶变换红外，电子自旋表征共振，紫外可见漫反射光谱和光致发光分析。较低的Si量使ZrO ₂完全稳定在四方相（t -ZrO ₂），但SiZr晶格中较高的Si占据氧空位（OV）以引入低单斜晶相含量破坏催化剂。按以下顺序对2-氯苯酚（2-CP）的光降解催化剂活性进行排序：1SiZr（92％）> TiO ₂（73％）> 2SiZr（67％）> 3SiZr（64％）> 4SiZr（56 ％）> ZrO ₂（51％）。该结果表明，使用0.375 g L ^-1时，1SiZr在pH 5时降解率最高，为10 mg L ^-1 2-CP催化剂在可见光照射下4小时内。1SiZr的最高光活性归因于较大的表面积和微晶尺寸，这导致与光的良好表面接触，从而加快了光催化活性。此外，1 SiZr所具有的最高OV量通过充当电子受体有效地抑制了电子-空穴复合，从而影响了t -ZrO ₂稳定以及催化活性。2-CP的光催化降解动力学与伪一级模型相关，表面反应为控制步骤。如清除剂研究所证实，光生空穴是最活跃的物种。1SiZr经过五次运行后仍保持了光催化活性，并具有强大的降解各种酚类衍生物的能力，表明其在酚类废水处理中的潜在用途。

图形摘要