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Research has demonstrated that the formation of composites of titanium dioxide (TiO2) with silver phosphate (Ag3PO4) through the construction of heterojunctions can expand its light absorption range and suppress the recombination of photogenerated electron–hole pairs, thereby improving the photocatalytic performance. However, this method offers only limited performance improvements, and the composite photocatalysts are costly due to the expensive Ag3PO4. In this study, Ti3C2 MXene, which has good hydrophilicity and excellent electrical conductivity, is first used to form Schottky junction composites with bronze TiO2 (TiO2(B)) via electrostatic self-assembly. Then, Ag3PO4 quantum dots were further formed on the surface of the TiO2(B)/Ti3C2 MXene by in situ self-growth, and Ag3PO4 formed heterojunctions and Schottky junctions with TiO2(B) and Ti3C2 MXene, respectively. Finally, a ternary composite photocatalyst TiO2(B)/Ti3C2 MXene/Ag3PO4 was jointly constructed by these functional junctions. Under the synergistic effect of these functional junctions, the mobility and fast separation performance of photogenerated electron–hole pairs of the composite photocatalyst were significantly improved, the recombination of photogenerated electron–hole pairs was effectively suppressed, and the light absorption performance was enhanced. As a result, the composite photocatalyst exhibited excellent photocatalytic performances. [ABSTRACT FROM AUTHOR]

Photocatalytic technology is currently the most promising technology for environmental pollution control. The preparation of photocatalysts with excellent properties is the core of the development of photocatalytic technology. TiO2 can form a heterojunction with g-C3N4, which can effectively inhibit the recombination of photogenerated electron–hole pairs, improve the mobility of photogenerated carriers, and thus improve the photocatalytic performance. In this study, NaCl was used as a template, and the loose and porous g-C3N4/TiO2 heterojunction composite photocatalysts were prepared by the template method. Compared to the pure g-C3N4 prepared by the conventional thermal polycondensation method and TiO2, the g-C3N4/TiO2 heterojunction composite photocatalysts prepared in this study exhibited a greatly increased specific surface area, an improved light absorption performance, a significantly suppressed recombination of photogenerated electrons and holes. Furthermore, the g-C3N4/TiO2 heterojunction composite photocatalysts exhibited excellent photocatalytic performance. In this study, NaCl was used as a template, and the loose and porous g-C3N4/TiO2 heterojunction composite photocatalysts were prepared by the template method. Compared to the pure g-C3N4 prepared by the conventional thermal polycondensation method and TiO2, the g-C3N4/TiO2 heterojunction composite photocatalysts prepared in this study exhibited a greatly increased specific surface area, an improved light absorption performance, a significantly suppressed recombination of photogenerated electrons and holes. Furthermore, the g-C3N4/TiO2 heterojunction composite photocatalysts exhibited excellent photocatalytic performance. [ABSTRACT FROM AUTHOR]

There has been increasing concern over water pollution, which poses a threat to human life and health. Absorption by low-cost absorbents is considered to be a cost-effective and efficient route. However, the non-reusability of absorbents greatly limits their applications. In this study, a novel vermiculite/TiO2 composite combining the inexpensive absorbent with the commonly used photocatalyst was firstly synthesized via the sol-gel method. On the one hand, the organic pollutants are absorbed by vermiculite and then decomposed through the photocatalysis process, enabling the next round of absorption and creating an absorption–decomposition reusable cycle. On the other hand, the modulation effect of optical and electronic structure on the prepared TiO2 photocatalyst by the vermiculite incorporation could significantly improve the photocatalytic activity and eventually enhance the aforementioned cyclic degradation capacity. The layer-structured vermiculite (Vt) supports a uniform coverage of TiO2 at an optimized ratio, providing an optimal adsorption environment and contact area between the photocatalyst and methylene blue (MB) molecules. Vt/TiO2 heterojunction is formed with Si-O-Ti bonding, at which electrons transfer from Vt to TiO2, enriching electron density in TiO2 and favoring its photocatalytic activity. Furthermore, the incorporation of Vt increases the light absorption of TiO2 in the visible range by narrowing the optical band gap to 1.98 eV, which could promote the generation of photo-excited carriers. In addition, PL measurements revealed that the carrier recombination is substantially suppressed, and the charge separation and migration are greatly enhanced by a factor of 3. As a result, the decomposition rate of MB is substantially increased 5.3-fold, which is ascribed to the synergistic effects of the elevated photocatalysis and the large absorption capacity governed by the chemisorption mechanism of the intra-particle diffusion. These results pave the way for composite design towards efficient, economical, and pragmatic water pollution treatment. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation, as an emerging method to control environmental pollution, is considered one of the most promising environmental purification technologies. As Tibet is a region with some of the strongest solar radiation in China and even in the world, it is extremely rich in solar energy resources, which is ideal for applying photocatalytic technology to its ecological environment protection and governance. In this study, Na2Ti3O7 nanobelts were prepared via a hydrothermal method and converted to TiO2∙xH2O ion exchange, which was followed by high-temperature calcination to prepare TiO2(B) nanobelts ("B" in TiO2(B) means "Bronze phase"). A simple in situ method was used to generate Ag3PO4 particles on the surface of the TiO2 nanobelts to construct a Ag3PO4/TiO2(B) heterojunction composite photocatalyst. By generating Ag3PO4 nanoparticles on the surface of the TiO2(B) nanobelts to construct heterojunctions, the light absorption range of the photocatalyst was successfully extended from UV (ultraviolet) to the visible region. Furthermore, the recombination of photogenerated electron–hole pairs in the catalyst was inhibited by the construction of the heterojunctions, thus greatly enhancing its light quantum efficiency. Therefore, the prepared Ag3PO4/TiO2(B) heterojunction composite photocatalyst greatly outperformed the TiO2(B) nanobelt in terms of photocatalytic degradation. [ABSTRACT FROM AUTHOR]