Abstract

In order to produce a photocatalyst with increased visible photocatalytic ability, MIL-125 and melamine were selected as raw materials to prepare Z-scheme g-C₃N₄/TiO₂ heterojunction photocatalyst using a simple calcination method. TEM, HRTEM, XRD, FTIR, EDS, and UV–vis absorption spectra were employed to investigate the prepared specimens. The visible-light catalytic property was examined via the degradation of methylene blue (MB). The recombination and separation activity of electrons and holes (h⁺/e⁻) were explored by the transient photocurrent response (TPR) and PL spectra. In contrast with plain TiO₂ and g-C₃N₄, the g-C₃N₄/TiO₂ photocatalyst exhibited increased photocatalytic activities when exposed to visible-light irradiation. With the addition of g-C₃N₄ at 8 wt%, the Z-scheme g-C₃N₄/TiO₂ heterojunction performed best in the photocatalytic test toward MB dye at a degradation rate of 97.7%. Under visible-light irradiation, the Z-scheme heterojunction between g-C₃N₄ and TiO₂ enables the high-efficient segregation of photogenic electrons and holes (h⁺/e⁻), leading to the increased photocatalytic ability. Meanwhile, the large specific surface area of the composite photocatalyst is conducive to the adsorption of the contaminant on the catalyst surface, which has an important effect on the catalytic reaction.

The direct Z-scheme g-C₃N₄/TiO₂ was obtained by an in-situ heat treatment process with MIL-125 (Ti) and melamine as raw materials. The g-C₃N₄/TiO₂ photocatalyst with 8 wt% g-C₃N₄ exhibited the optimal degradation efficiency, which was due to the high separation efficiency of photogenic electrons and holes (h⁺/e⁻) of the Z-scheme heterojunction.

中文翻译：

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MOF衍生的直接Z方案gC 3 N 4 / TiO 2具有增强的可见光催化活性

摘要

为了生产具有增加的可见光催化能力的光催化剂，选择MIL-125和三聚氰胺作为原料，以简单的煅烧方法制备Z-方案gC ₃ N ₄ / TiO ₂异质结光催化剂。用TEM，HRTEM，XRD，FTIR，EDS和UV-vis吸收光谱研究制备的标本。通过亚甲基蓝（MB）的降解检查了可见光催化性能。电子和空穴（h的再结合和分离的活动⁺ / E ^{- ）}由瞬态响应光电流（TPR）和PL光谱的探讨。与普通的TiO ₂和gC ₃ N _4相比，gC当暴露于可见光照射下，₃ N ₄ / TiO ₂光催化剂显示出增加的光催化活性。通过添加8wt％的gC ₃ N ₄，Z-方案gC ₃ N ₄ / TiO ₂异质结在对MB染料的光催化试验中表现最好，降解率为97.7％。下可见光照射，GC之间的Z-方案异质结₃ Ñ ₄和TiO ₂使上相电子和空穴（h的高效偏析⁺ / E ^-），导致增加的光催化能力。同时，复合光催化剂的大比表面积有利于污染物在催化剂表面上的吸附，这对催化反应具有重要影响。