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Mesoporous TiO2–SiO2 films with remarkable self-cleaning capability were prepared by Sol–Gel methods and pressureless sintering. Here, the results show that the incorporation of 20 V% SiO2 onto the TiO2 films enhances the performance of anti-fog and self-cleaning. According to the SEM image, it is found that the TiO2 particles are dispersed by the SiO2, thus enlarging the specific surface area of the TiO2 particles. Therefore, super hydrophilicity and self-cleaning performance are promoted. Besides, the mesoporous structure is formed on the surface of the TiO2–SiO2 films after calcination. The mesoporous structure can improve the light utilization efficiency and the surface roughness of the films, thus promoting the performance of super hydrophilicity. Consequently, the mesoporous TiO2–SiO2 composite films as environmentally friendly coatings presented great potential in environmental governance.

The combined activation effects of photogenerated e−/h+, Fe, Co, Mn, and Zn on peroxymonosulfate to produce SO4˙− clearly enhanced the degradation efficiency.

Low-overpotential layered hydroxides (LDHs) with high theoretical capacity are promising electrodes for supercapaterry and oxygen evolution reaction; however, the low electronic conductivity and insufficient active sites of bulk LDHs increase the internal resistance and reduce the capacity and oxygen-production efficiency of electrodes. Herein, we prepared a polyaniline-coated NiCo-layered double hydroxide intercalated with MoO42− (M-LDH@PANI) composite electrode using a two-step method. As the amount of MoO42− in the LDH increases, acicular microspheres steadily evolve into flaky microspheres with a high surface area, providing more active electrochemical sites. Moreover, the amorphous PANI coating of M-LDH boosts the electronic conductivity of the composite electrode. Accordingly, the M-LDH@PANI at an appropriate level of MoO42− exhibits significantly enhanced energy storage and catalytic performance. Experimental analyses and theoretical calculations reveal that a small amount of MoO42− is conducive to the expansion of LDH interlayer spacing, while an excessive amount of MoO42− combines with the H atoms of LDH, thus competing with OH−, resulting in reduced electrochemical performance. Moreover, M-LDH flaky microspheres can efficiently modulate deprotonation energy, greatly accelerating surface redox reactions. This study provides an explanation for an unconventional mechanism, and a method for the modification of LDH-based materials for anion intercalation.

A novel Janus MoSiGeN

CoFe-NiOOH is developed for the first time as a ternary polymetallic surface oxygen evolution cocatalyst to enhance the photoelectrochemical (PEC) water splitting performance of BiVO4-based photoan...

Improving the sensitivity of MoS2-based photodetectors by constructing semiconductor heterostructures remains a challenge. To address this issue, the effects of interlayer spacing and vertical external electric fields on the interfacial interactions and electronic properties of Zr2CO2/MoS2 heterostructures were investigated systematically by first-principles calculations. The results indicate that a stable interface with van der Waals interactions can form between Zr2CO2 and MoS2, which complies with the type-II mechanism. By applying a vertical external electric field to the Zr2CO2/MoS2 heterostructure or changing the interlayer spacing between the Zr2CO2 and MoS2 monolayers, both the band gap and heterostructure type at the Zr2CO2/MoS2 interface can be modulated efficiently. It is remarkable that the band alignment of the Zr2CO2/MoS2 heterostructure is more sensitive to the external electric field than to the interlayer spacing. When the electric field is from −0.5 to 0.5 V A−1, the energy band of the Zr2CO2/MoS2 heterostructure changes from 0.2 to 0.3 eV with a 0.1 V A−1 increase of electric field. The redistribution of charge density with the external electric field and interlayer coupling is revealed to account for the tunable energy bands. Therefore, the Zr2CO2/MoS2 heterostructures with van der Waals interactions possess great potential to be used in high-performance photodetectors.

The two-dimensional semiconductor photocatalytic material has excellent photocatalytic H2 evolution activity. In order to further improve the hydrogen production activity of g-C3N4, this study improved the preparation process of g-C3N4 and obtained a new photocatalyst (name H-CN) with a higher absorption range, larger specific surface area, and faster hydrogen production activity. Compared with the originally prepared g-C3N4, the H-CN absorption range has been improved, and the utilization of visible light has reached 650 nm. When the doping amount of Pt cocatalyst was 1.0 wt%, the H-CN demonstrates excellent photocatalytic hydrogen production activity, with a hydrogen production rate of 4.3 mmol h−1·g−1, which was 7.0 times higher than that pure 1.0 wt% Pt/g-C3N4. The fluorescence spectroscopy of H-CN showed better separation of carriers and longer lifetime. This study has guiding significance for the preparation of subsequent ultra-thin nanosheet photocatalysts and the establishment of high-efficiency photocatalytic systems.

Despite the impressive development of CH3NH3PbI3(MAPbI3)-based perovskite solar cells (PSCs) in device efficiency, they are limited by their low stability due to the moisture-induced degradation of...

Bi2WO6/Bi2MoO6 heterostructured photocatalys had been synthesized by a refluxing method. And the photocatalytic activity of Bi2WO6/Bi2MoO6 heterostructured photocatalysts was better than Bi2WO6. The enhancement in photocatalysis activity belonged to the match of energy level between the Bi2MoO6 and Bi2WO6. In order to further enhance the photocatalytic activity of Bi2WO6/Bi2MoO6, Bi2WO6/Bi2MoO6 was used to activate peroxymonosulfate to photodegradate methylene blue. The mechanism of activating peroxymonosulfate was proved by radical quenching experiment which revealed that sulfate radicals governed the removal of methylene blue.

ZnSn(OH)6 and Zn2SnO4 were synthesized by a simple hydrothermal method. The influences of reaction conditions on the formation of ZnSn(OH)6 and Zn2SnO4 were investigated in detail. ZnSn(OH)6 and Zn2SnO4 showed highly efficient photocatalytic activity for the degradation of methylene blue under ultraviolet light irradiation. Kinetic studies using radical scavenger technologies suggested that hydroxyl radicals were the dominant photooxidants. On the basis of the experimental results, the excellent photocatalytic activities of ZnSn(OH)6 were mainly attributed to the hydroxyl groups which were part of the ZnSn(OH)6 lattice. The recovery of hydroxyl groups could make up for the consumption.

The CeO2/g-C3N4 hybrid is a kind of efficient photocatalyst with both photoinduced oxidation and reduction capability, which is of great concern in solar energy application. Herein, we reported a facile method for the synthesis of the CeO2/g-C3N4 hybrid with enhanced CO2 reduction and ciprofloxacin degradation performance using surface carboxylated g-C3N4 (C-g-C3N4) as the substrate. The characterization results demonstrated the abundant oxygen-containing groups of C-g-C3N4 in the CeO2/C-g-C3N4 hybrid can effectively improve the dispersion of CeO2 nanoparticles and enhance the interfacial bonding with the C-g-C3N4 substrate. Density functional theory (DFT) calculations showed that a built-in electric field was formed in the CeO2/C-g-C3N4 heterojunction, which can greatly improve the charge separation and transfer efficiency. Consequently, the yield of CO and the ciprofloxacin degradation efficiency have been remarkably improved. The maximum CO yield through CO2 photoreduction over 3%CeO2/C-g-C3N4 was 9.083, 3.922, and 2.868 times higher than that of pure CeO2, C-g-C3N4 and 3%CeO2/g-C3N4 bulk, respectively. The 3%CeO2/C-g-C3N4 heterojunction also showed excellent photoinduced oxidation activity for ciprofloxacin degradation with a 73% degradation efficiency in 2 h, which was 1.89 and 2.76 times higher than that of pure CeO2 and C-g-C3N4, respectively. Furthermore, a good photostability for a five cycle test of CO2 reduction was observed over the 3%CeO2/C-g-C3N4 hybrid. The possible photocatalytic mechanism was investigated by theoretical calculations and capture experiments to further understand the charge transfer behavior over the CeO2/C-g-C3N4 heterojunction for CO2 reduction and pollutant degradation.

Magnetic BiOBr/Fe3O4/RGO composites with remarkable photocatalytic capability were prepared by a simple hydrothermal method to load 3D flower-like microspherical BiOBr onto the surface of Fe3O4/RGO. Under visible-light irradiation (λ > 420 nm), the BiOBr/Fe3O4/RGO composite with 56% mass percentage of Fe3O4/RGO shows the optimal removal ability for Rhodamine B, and the total removal efficiency is 96%. The coupling of Fe3O4/RGO and BiOBr elevates the conduction band of BiOBr, which enhances the reduction level of BiOBr/Fe3O4/RGO composites. Ultimately, based on experiments and theoretical calculations, an n-type Schottky contact formed at the heterojunction interface between RGO doped with Fe3O4 and BiOBr is proposed for photoexcited charge transfer. The RGO with great adsorptivity plays a major role in the photocatalysts composed of BiOBr, RGO and Fe3O4. Further, BiOBr/Fe3O4/RGO composites with permanent-magnetism can be recovered and reused easily by external magnetic field and maintain a total removal efficiency of 90% after four cycles.

An understanding of the high photocatalytic performance reported for MoS2/BiOI nanocomposite is far from satisfactory. Here, the interfacial interaction and electronic properties of a MoS2/BiOI heterostructure were investigated systematically for the first time by first-principle calculations incorporating a semi-empirical dispersion-correction scheme. Our results confirm the reasonable existence of van der Waals interactions and a favorable Z-scheme mechanism, based on the typical interfacial cohesive energy and the energy level lineup at the interface. Analyzing the charge density differences and work functions, the built-in electric field is formed along the direction from MoS2 to BiOI after the interface equilibrium, and facilitates the separation of photoinduced electron–hole pairs in the interface. Additionally, it can be inferred that the incorporation of MoS2 into BiOI increases the carrier mobility and improves light harvesting, in agreement with the previously reported experimental data. Our work provides an insight into the mechanism of the enhanced visible-light photocatalytic activity of a MoS2/BiOI heterostructure, and helps to design other new heterostructure combinations.

A strategy is proposed for modifying BiVO4 photoanode with CoNiO2 as a novel water oxidation cocatalyst to enhance PEC water splitting performance. The results show that CoNiO2 has the following functions: reducing photogenerated charge recombination centers; providing trapping sites to promote charge separation; improving the stability of the overall system; providing more active sites; and offering a lower overpotential. The BiVO4/CoNiO2 photoanode has a higher photocurrent density (1.16 mA cm-2 at 1.23 V vs. RHE), a lower onset potential (∼0.06 V vs. RHE), a larger IPCE (34.37%) and ABPE (0.163%), better stability and good rates of hydrogen evolution (0.0148 μmol cm-2 min-1) and oxygen evolution (0.0076 μmol cm-2 min-1). The strategy provides promising prospects for achieving efficient PEC water splitting performance using water oxidation cocatalysts.

Maximizing the activity of materials towards the alkaline hydrogen evolution reaction while maintaining their structural stability under realistic working conditions remains an area of active research. Herein, we report the first controllable surface modification of graphene(G)/V8 C7 heterostructures by nitrogen. Because the introduced N atoms couple electronically with V atoms, the V sites can reduce the energy barrier for water adsorption and dissociation. Investigation of the multi-regional synergistic catalysis on N-modified G/V8 C7 by experimental observations and density-functional-theory calculations reveals that the increase of electron density on the epitaxial graphene enable it to become favorable for H* adsorption and the subsequent reaction with another H2 O molecule. This work extends the range of surface-engineering approaches to optimize the intrinsic properties of materials and could be generalized to the surface modification of other transition-metal carbides.

Herein, a wide-spectrum (∼678 nm) responsive Bi8(CrO4)O11 photocatalyst with a theoretical solar spectrum efficiency of 42.0% was successfully constructed. Bi8(CrO4)O11 showed highly efficient and stable photocatalytic water oxidation activity with a notable apparent quantum efficiency of 2.87% (420 nm), superior to many reported wide-spectrum driven photocatalysts. Most remarkably, its strong oxidation ability also enables the simultaneous degradation and complete mineralization for phenol, and its excellent performance is about 23.0 and 2.9 times higher than CdS and P25-TiO2, respectively. Its high activity is ascribed to the giant internal electric field induced by its large crystal dipole, which accelerates the rapid separation of photogenerated electron–hole pairs. Briefly, the discovery of wide-spectrum bismuth chromate and the mechanism of exponentially enhanced photocatalytic performance by increasing the crystal dipole throw light on improving solar energy conversion.

As the photovoltaic performance of mesoscopic perovskite solar cells (PSCs) is strongly dependent on the interface between perovskite and electron transport layer. Herein, an attempt to load facile processed ZnO quantum dots (ZQDs) or TiO2 quantum dots (TQDs) into the mp-TiO2 layer via a simple spin-coating method was first performed. Both of them had huge impact on the morphology of perovskite films, leading to larger perovskite grains. However, the power conversion efficiency (PCE) of these two kinds of QDs modified cells exhibited a different tendency. The champion PCE of ZQDs modified PSCs was remarkably improved from 14.54% to 17.2%, while that of TQDs modified ones decreased to 11.78%. We demonstrated that the enhanced PCE and short-circuit current (Jsc) were attributed to the enlarged grain size and enhanced light absorption of perovskite film, faster electron extraction and transport as well as less recombination for ZQDs modified PSCs, which mainly resulted from the increased active specific surface area. On the contrary, deterioration of TQDs modified PSCs was exactly ascribed to the aggregation of TQDs which sharply decreased the specific surface area of the electron transport layer. The current work provided an efficient and facile way to improve the photovoltaic performance of mesoscopic PSCs.

A two-dimensional (2D)/three-dimensional (3D) hybrid heterostructure has recently emerged as an effective method for improving photocatalytic efficiency. In this work, we perform a comprehensive first-principles study of the structural, electronic, and optical properties of a novel 3D-SiC/2D-MoS2 heterostructure. The calculation results reveal that the SiC(0001) surface/MoS2 monolayer-integrated heterostructure in Schottky contact with a new chemical bonding contributed to the surface adhesion and optoelectronic properties. Meanwhile, the valence and conduction band-edge positions of SiC and MoS2 changed with the Fermi level and formed a desired type-II band alignment, which greatly facilitate the rapid separation of photogenerated carriers. Moreover, the surface state of SiC(0001) can be removed when combined with MoS2, and their band gap is also reduced. Furthermore, Bader charge and charge density difference indicated that there is a remarkable separated distribution of electrons and holes at the inter...

Nitrogen reduction reactions (NRRs) under mild conditions retain an enormous challenge in effective N2 activation on metal-based catalysts. Here, by spin-polarized DFT calculations, we systematically investigated the potential of single transition-metal atoms (Sc to Zn, Nb to Cd, W, Pt and Au) supported on the experimentally available WS2 nanosheets with sulfur vacancies as catalysts for N2 fixation and conversion. The results confirm that the WS2 nanosheet with sulfur vacancies is a good platform for anchoring single transition-metal atoms. Based on proposed several criteria, it is found that the single Ni atoms anchored to sulfur vacancies possess outstanding catalytic activity of NRR. Here, the Ni-WS2 nanosheet acts as likely Lewis-acid system and accepts electrons from the N2*, which causes the weakening of N–N bond. Reaction energy diagrams of the NRRs show that the whole NRRs on Ni-WS2 surface prefer to occur along the alternating associative pathway, and form the ammonia without the requirement of energy input. Overall, our results reveal that the Ni-WS2 system is a quite promising single-atom catalyst with less energy-consuming and good stability for NRRs. These findings could motivate more experimental and theoretical researches to further explore the potential of single transition-metal atoms anchored to two-dimensional substrate materials for NRRs.

Understanding is far from satisfactory on the high photocatalytic performances of g-C3N4/WS2 nanocomposites which are experimentally reported. Here, we investigate systematically for the first time the interfacial interactions and electronic properties of triazine-based g-C3N4/WS2 nanocomposites by first-principles calculations. The results confirm the reasonable existence of vdW interaction and typical direct Z-scheme mechanism based on the prominent interfacial binding energies and the energy level lineup at interface. Both energy band structures and work functions show that the conduction and valence band edges of the g-C3N4 layer are more negative than those of the WS2 layer after their intimate contact, respectively. Meanwhile, the interfacial interaction makes WS2 with negative charges and g-C3N4 with positive charges, forming a built-in electric field from g-C3N4 to WS2. Thus, photogenerated e––h+ pairs are separated to different places with prolonged lifetime and high redox potential. This work shines some lights on a direct Z-scheme mechanism for the g-C3N4/WS2 heterostructured photocatalyst.

Controlling the p-type electrical transport behavior of nanoelectronic devices remains a grand challenge in reducing the Schottky barrier. To address this issue, we systematically investigate the effect of asymmetric Se doping on the interlayer interaction and electronic properties of a MoS2(1−x)Se2x/graphene heterostructure by first-principles calculations incorporating a semiempirical dispersion–correction scheme. The results show that the interfacial binding can be enhanced by Se doping inside the interface, while the effect of Se doping outside the interface is negligible on the interfacial binding. The type and height of the Schottky barrier can be tuned by changing the concentration and sites of the Se dopant at the interface. Further, it is found that by increasing the concentration of the Se dopant inside the interface the transition from an n-type Schottky barrier to a p-type can be realized, and a low p-type Schottky barrier is gained at the interface for highly efficient charge transfer. Lastly, it is confirmed that the redistribution of the interfacial charge leads to a shift of the Fermi level, and thus determines the type and height of the Schottky barrier. These conclusions provide rational evidence for the asymmetric doping concepts to design and fabricate MoS2-based field effect transistors.

The surface properties of BiPO4 exert a significant effect on the photocatalytic performance under ultraviolet irradiation, but they have not been well explored, either experimentally or theoretically. Herein, for the first time, we systematically studied the structures and energetics of four low-index stoichiometric surfaces of monazite BiPO4 using density functional theory. A new scheme is proposed to correct the surface energy and compare this with the average surface energy. Both of the two schemes for the surface energies indicate that the order of the surface energies is (100) < (010) < (011) < (001), which is not completely consistent with their surface dangling bond densities. The main reason is incomplete PO4 tetrahedrons, namely, the existence of dangling P–O bonds in the bare (001) plane. However, only dangling Bi–O bonds are found in the other three low-index surfaces. It is obvious that the dangling bond density of the Bi atoms and the intact PO4 tetrahedrons are two crucial factors in the surface stability. Correspondingly, the differences in the planar-averaged electron density and the work function are presented to describe the charge distribution close to the surface. Furthermore, the equilibrium morphology calculated using the Wulff construction suggests that the (001), (010), (011) and (100) facets account for 15%, 33%, 16% and 36%, respectively. The two low-energy (100) and (010) facets dominate in the Wulff shape and make up almost 69% of the total crystal shape area. This work will provide theoretical guidance for the further design of effective BiPO4-based photocatalysts.

In this work, we aimed to develop a novel method for the target preparation of multicomponent composites Au@CdS/g-C3N4 towards high visible light photocatalytic activity with the assistance of L-cysteine biomolecules. Through the interaction of L-cysteine biomolecules with Au nanoparticles and g-C3N4 bulks, CdS layer were in-situ precipitated on the surface of Au nanoparticles to form core-shell structure Au@CdS and Z-scheme structure Au@CdS-g-C3N4 with good interface bonding in composites. By taking advantage of this feature, the highest reaction rate constant of 8%Au@CdS/g-C3N4 for methyl orange dye and phenol degradation was 3.08- and 1.48-folds higher than pure g-C3N4 bulks, which was ascribed to the strong interaction between different substances for efficient charges transferring and separation as evidenced by the studies of X-ray photoelectron spectroscopy, steady-state and transient photoluminescence spectroscopy. This work highlights the utilization of biomolecules for the target preparation of composites and its application on environmental remediation.

A strategy is proposed for modifying BiVO

The two-dimensional semiconductor photocatalytic material has excellent photocatalytic H

Solar-to-chemical energy conversion is valuable and sustainable strategy for energy and environmental crisis through photocatalysis. The amorphous SnOx modified BiOCl (Sn-BiOCl) full-spectrum-responsive catalysts were designed and synthesized through solvothermal method. The introduced Sn regulates the growth of BiOCl to form ultrathin nanosheets with surface oxygen vacancies. And the surface modification of SnOx induces interfacial internal electric field via charge redistribution on the interface of BiOCl and SnOx to accelerate the photogenerated charge separation. The modification of SnOx decreased work function of Sn-BiOCl and thus elevated its conduction band and valence band simultaneously, leading enhanced photocatalytic reducibility with the improved generation rate of ·O2-. The surface SnOx and oxygen vacancies of Sn-BiOCl broadened light absorption range and enhanced photocatalytic performance synergistically, resulting in 14-fold increased photodegradation rate of phenol compared with pure BiOCl under full spectrum. This method is also able to expand to other metal ions (such as Fe3+, In3+ and Sb3+). This work provides a valuable concept in structure regulating for enhanced photocatalytic performance in the removal of organic pollutants by interfacial internal electric field and surface oxygen vacancies.

Magnetic BiOBr/Fe