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Constructing the hetrostructure is a feasible strategy to enhance the performances of photocatalysts. However, there are still some fundamental details and mechanisms for the specific design of photocatalysts with heterostructure, which need further confirming and explain. In this work, g-C3N4-based heterostructures are constructed with TiO2 in different ways, and their intrinsic factors to improve the photocatalytic activity are systematically studied by density functional theory (DFT). When g-C3N4 combines horizontally with TiO2 to form a heterostructure, the interaction between them is dominated by van der Waals interaction. Although the recombination of photo-generated electron–hole pair cannot be inhibited significantly, this van der Waals interaction can regulate the electronic structures of the two components, which is conducive to the participation of photo-generated electrons and holes in the photocatalytic reaction. When the g-C3N4 combines vertically with TiO2 to form a heterostructure, their interface states show obvious covalent features, which is very beneficial for the photo-generated electrons' and holes' transport along the opposite directions on both sides of the interface. Furthermore, the built-in electric field of g-C3N4/TiO2 heterostructure is directed from TiO2 layer to g-C3N4 layer under equilibrium, so the photo-generated electron–hole pairs can be spatially separated from each other. These calculated results show that no matter how g-C3N4 and TiO2 are combined together, the g-C3N4/TiO2 heterostructure can enhance the photocatalytic performance through corresponding ways. [ABSTRACT FROM AUTHOR]

Mixed-phase (i.e. phase junction) TiO 2 has been widely used in commercial photocatalysis applications, because of its excellent photocatalytic performance. However, the interfacial composition, micro-structure, and properties of mixed-phase TiO 2 are not fully understood so far. Consequently, the phase transition process TiO 2 from anatase to rutile is still not entirely clear; and there is no consensus on the mechanism of mixed-phase enhancing photocatalytic performance of TiO 2. In this article, 16 interface models for TiO 2 phase junctions were constructed by the low-index surfaces of TiO 2 with anatase and rutile phases. The interfacial energy, microstructure, electronic structure and properties have been systematically calculated and analyzed. Based on the interfacial formation energy and the configuration of [TiO 6 octahedron at A/R interface, the phase transition of TiO 2 is most likely to occur at the interface between anatase (110) plane and rutile (011) plane, owing to the favorable interface formation energy and the smallest deformation of [TiO 6 octahedrons. However, because the migration direction of photo-generated carriers is opposite to the direction of the built-in electric field at the A/R interface in A(110)/R(011) phase junction, the hetero-direction migration of photo-generated electron-hole pairs will be prevented. Thereby, the existence of A(110)/R(011) phase junction is unfavorable to improve the photocatalytic performance. On the other hand, when the calcination temperature rises, the favorable phase junctions (such as A(110)/R(001) phase junction) gradually occupies the growth advantage, which can improve the photocatalytic performance of TiO 2. This is a possible explanation for the excellent photocatalytic properties of Degussa P25 with mixed-phase. • 16 TiO 2 phase junctions were constructed by the low-index surfaces of TiO 2 with anatase and rutile phases. • The phase transition of TiO 2 is most likely to occur at the interface between anatase (110) plane and rutile (011) plane. • The existence of A(110)/R(011) phase junction is unfavorable to improve the photocatalytic performance. • When favorable phase junctions gradually occupy the growth advantage, they can improve the photocatalytic performance. [ABSTRACT FROM AUTHOR]

Composite photocatalyst with heterostructure is often recognized as an effective strategy to achieve efficient charge separation and increase carrier concentration. In this study, the (1 1 0) and (1 0 1) surfaces of TiO 2 and SnO 2 were chosen to construct the abrupt and graded TiO 2 /SnO 2 hetero-structures. The interface properties and band offsets of four heterostructures are calculated and analyzed in detail. It was found that the graded heterostructures are more stable and easier to preparation than the abrupt heterostructures, the charge depletion and accumulation occur at both ends of the transition layer. The interfacial electric field caused by this effect allows the photo-generated electron-hole pairs to be easily separated and transferred in the opposite direction at the interface, which is important for improving the photocatalytic activity. In addition, the intrinsic mechanism of the four hetero-structures is discussed according to the analysis of the band offset, which belongs to the type II heterostructures. For TiO 2 /SnO 2 -(1 1 0) heterostructure, the photo-generated electrons transfer from the conduction band of TiO 2 to the conduction band of SnO 2 , while the photo-generated holes transfer from the SnO 2 to the valence band of TiO 2 . This phenomenon leads to the accumulation of the photo-generated electrons in the conduction band of TiO 2 , accumulation of the photo-generated holes in the valence band of SnO 2 . In short, the graded heterostructure has more favorable effects to enhance the photocatalytic activity than that of the abrupt heterostructure. The internal electric field at the TiO 2 /SnO 2 interface acts as a selector for photo-generated carriers, which may lead to higher photocatalytic quantum efficiency and carrier concentration under the same external conditions. These intrinsic photocatalytic mechanisms and the interpretation of the interfacial microscopic properties of heterostructure can be used as a basis for the design of the sensing devices and composite photocatalysts with heterostructures. [ABSTRACT FROM AUTHOR]

Effective separation and fast transport of photogenerated carriers are vital links determining the photocatalytic performance. Heterostructure constructed by two complementary semiconductors is a feasible strategy to achieve this goal. By one‐pot hydrothermal method, 0D‐TiO2 nanoparticles are loaded onto 2D‐CuGaO2 nanosheets, forming a mixed dimension, closely combined heterostructure. The photocurrent density of CuGaO2/TiO2 heterostructure is ∼16.6 μA/cm2, which is 1.24 times higher than that of pristine CuGaO2 nanosheets (∼13.4 μA/cm2) and 15 times higher than that of TiO2 (∼1.1 μA/cm2). In the tetracycline hydrochloride degradation experiment, the degradation efficiency of tetracycline hydrochloride by CuGaO2/TiO2 heterostructure reached 99% within 90 min, which was 1.2 times the degradation efficiency of CuGaO2 nanoparticles (82%) and 20.2 times the degradation rate of TiO2 (4.9%). A series of experimental characterizations combined with density functional theory calculations revealed that it is the built‐in electric field in the CuGaO2/TiO2 interface region that drives the photogenerated electron–hole pairs to travel in the opposite direction, thus inhibiting their recombination. Furthermore, the energy band offset of the CuGaO2/TiO2 interface makes it easier for the photogenerated holes and electrons to gather onto the valence band of the CuGaO2 nanosheets and the conduction band of the TiO2 nanoparticles, respectively. Therefore, appropriate interface lattice matching, suitable configuration of band gap and band edge positions, and strong opposite drive of interface electric field enable CuGaO2/TiO2 heterostructure to achieve wide spectral response and effective separation of photogenerated electron–hole pairs at the same time. [ABSTRACT FROM AUTHOR]

Conventional drying, dehumidification drying, and combined conventional-dehumidification drying of wood were experimentally studied in this article. The results showed that the energy consumption in the dehumidification drying is the least but its drying time is the longest. The energy consumption in the combined drying is more than that in the dehumidification drying but less than that in the conventional drying, and the drying time is half of that in the dehumidification drying. The advantages of the combined conventional and dehumidification drying are discussed from the experiments results. [ABSTRACT FROM AUTHOR]

Enterovirus 71 (EV71) is the major causative agent of hand, foot and mouth disease (HFMD) in children, causing severe clinical outcomes and even death. Here, we report an important role of the highly conserved alanine residue at position 107 in the capsid protein VP1 (VP1A107) in the efficient replication of EV71. Substitutional mutations of VP1A107 significantly diminish viral growth kinetics without significant effect on viral entry, expression of viral genes and viral production. The results of mechanistic studies reveal that VP1A107 regulates the efficient cleavage of the VP0 precursor during EV71 assembly, which is required, in the next round of infection, for the transformation of the mature virion (160S) into an intermediate or A-particle (135S), a key step of virus uncoating. Furthermore, the results of molecular dynamic simulations and hydrogen-bond networks analysis of VP1A107 suggest that flexibility of the VP1 BC loop or the region surrounding the VP1107 residue directly correlates with viral infectivity. It is possible that sufficient flexibility of the region surrounding the VP1107 residue favors VP0 conformational change that is required for the efficient cleavage of VP0 as well as subsequent viral uncoating and viral replication. Taken together, our data reveal the structural role of the highly conserved VP1A107 in regulating EV71 maturation. Characterization of this novel determinant of EV71 virulence would promote the study on pathogenesis of Enteroviruses. [ABSTRACT FROM AUTHOR]