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In this paper, a novel preparation method (alkyne-based anionic method), had been used to prepare graphdiyne (GDY) with lamellar structure. Nanorods CoMoO 4 and nanosphere red phosphorus (P) was in situ loaded on the graphdiyne sheets using a morphology-modified method. Double S-type heterojunction of GDY/CoMoO 4 –P was built to improve the photocatalytic activity and stability. The hydrogen production of GDY/CoMoO 4 –P reached 14155.8 μmol g−1 h−1. The result of DFT theoretical calculation, ultraviolet and in-situ X-ray photoelectron spectroscopy characterization showed the construction of double S-type heterojunction accelerates the separation of photogenerated electrons/holes pairs and the transport of photogenerated electrons, enhance the absorption and utilization of light source. Through morphology control and heterojunction construction, the photocatalytic activity and stability was largely improved. This fully validates the feasibility that organic frameworks-GDY can be artificially constructed for photocatalytic hydrogen production. [Display omitted] • GDY/CoMoO 4 –P was successfully prepared by in situ deposition. • Design a ternary composite catalyst from the two aspects of morphology and band structure. • The addition of the GDY improves the redox ability of the entire system. • The recombination of photo-generated carriers was effectively suppressed. [ABSTRACT FROM AUTHOR]

A novel p-n heterojunction photocatalyst of CoMoO 4 /NiS-3 was constructed by electrostatic adsorption (In CoMoO 4 /NiS-3, the content of CoMoO 4 accounts for 30%). Through SEM and crystal structure, it can be seen that the composite catalyst has a starry flower morphology and is successfully synthesized. The fluorescence emission spectra show that CoMoO 4 /NiS-3 can accelerate the separation rate of photogenerated carriers. The electron transfer mechanism can be determined by ultraviolet characterization and electrochemical methods. Hydrogen evolution experiments can be observed that the amount of hydrogen evolution by the composite catalyst CoMoO 4 /NiS-3 is 225.1 μmol, which is 2.74 and 4.89 times higher than that of the CoMoO 4 and NiS catalysts, respectively. Through the control of the starry flower morphology and the contact interface of p-n heterojunction, the internal electric field is effectively constructed to inhibit the recombination rate of photogenerated carriers, which provides a powerful theoretical model for high performance hydrogen evolution reaction. The formation of p-n heterojunction effectively improves the transmission path of photogenerated carriers and greatly improves the performance of photocatalytic hydrogen evolution. [Display omitted] • The p-n heterojunction between NiS and CoMoO 4 has good stability. • Dispersion of NiS on CoMoO 4 is important for the hydrogen evolution reaction activity. • The electron transport path and hydrogen evolution mechanism of CoMoO 4 /NiS composite catalyst are proposed. • High-efficiency hydrogen evolution is realized through CoMoO 4 /NiS heterojunction. [ABSTRACT FROM AUTHOR]

With the increasing scarcity of resources, the search for green and available energy has become an urgent need. Among them, photocatalytic decomposition of water to hydrogen production has been widely studied. According to zeta potential and XRD characterization, NiCo2O4 and CuS were successfully reassembled by electrostatic self-assembly to construct S-scheme heterojunction induced by built-in electric site, which can accelerate the reaction. At the same time, under simulated visible light irradiation, the composite catalyst can rapidly decompose aqueous triethanolamine solution to produce hydrogen. The composite catalyst has high photocatalytic activity and shows a durable and efficient hydrogen generation effect. By studying the photogenerated carrier separation and transfer of the catalyst, the results show that the composite catalyst can accelerate the photogenerated carrier separation and transfer, so that it can participate in the photocatalytic reaction faster. It provides various insights into the construction of different heterojunctions in binary composite catalysts. [ABSTRACT FROM AUTHOR]

Phase engineering of two-dimensional transition metal dichalcogenides (2D-TMDs) offers opportunities for exploring unique phase-specific properties and achieving new desired functionalities. Here, we report a phase-selective in-plane heteroepitaxial method to grow semiconducting H-phase CrSe2. The lattice-matched MoSe2 nanoribbons are utilized as the in-plane heteroepitaxial template to seed the growth of H-phase CrSe2 with the formation of MoSe2-CrSe2 heterostructures. Scanning tunneling microscopy and non-contact atomic force microscopy studies reveal the atomically sharp heterostructure interfaces and the characteristic defects of mirror twin boundaries emerging in the H-phase CrSe2 monolayers. The type-I straddling band alignments with band bending at the heterostructure interfaces are directly visualized with atomic precision. The mirror twin boundaries in the H-phase CrSe2 exhibit the Tomonaga-Luttinger liquid behavior in the confined one-dimensional electronic system. Our work provides a promising strategy for phase engineering of 2D TMDs, thereby promoting the property research and device applications of specific phases. Phase engineering of 2D transition metal dichalcogenides enables the investigation of emerging physical properties. Here, the authors report a phase selective in-plane heteroepitaxial method to grow semiconducting H-phase CrSe2 thin films from MoSe2 nanoribbons, showing Tomonaga-Luttinger liquid behaviour in the CrSe2 mirror twin boundaries. [ABSTRACT FROM AUTHOR]

Inhibiting the recombination of photoexcited hole–electron pairs is the crucial for efficient hydrogen‐producing by photocatalytic water splitting under visible light. Although Ag2Mo2O7 has excellent photoelectrochemical properties and strong morphological plasticity, its hydrogen‐producing activity is inhibited due to its low separation efficiency of photogenerated carriers and small photoresponse range. Therefore, graphdiyne (GDY) is prepared using alkynyl anions and compounded with Ag2Mo2O7 by electrostatic self‐assembly. The hydrogen‐producing capacity of the composite catalyst GDY/Ag2Mo2O7 reaches up to 8156.6 μmol g−1 h−1, what is more, the photocatalytic hydrogen‐producing capacity of Ag2Mo2O7, GDY, and GDY/Ag2Mo2O7 is investigated by in situ X‐ray photoelectron spectroscopy, electrochemical testing, fluorescence analysis, and density functional theory calculation. The consequences display that the composite catalyst GDY/Ag2Mo2O7 shows the best fluorescence quenching effect and the highest photocurrent response intensity. In the final analysis, the preeminent photocatalytic hydrogen‐producing performance of the composition GDY/Ag2Mo2O7 is due to the establishment of type S heterojunction, and the migration rate of photogenerated electrons is increased and the migration path is shortened. This contributes a practical tactics to effectively enhance the capacity of photocatalytic hydrogen‐producing by solving the problem of serious recombination of photogenerated carriers. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production was a potential strategy to solve energy shortage and environmental pollution. One of the valuable research directions for improving photocatalytic efficiency was to prepare catalysts in an efficient and low-cost way. Lamellar Sm 2 WO 6 and dodecahedron Zeolitic Imidazolate Framework-67 (ZIF-67) have been prepared successfully based on morphology control. Sm 2 WO 6 /ZIF-67 was prepared by a novel in situ growth scheme, which was confirmed by crystal structure, morphology and elemental composition analysis. The close interaction between Sm 2 WO 6 and ZIF-67 was confirmed by photoelectrochemical measurements. Based on the design of band structure, the S-type heterojunction was constructed. The research results of this paper provided a reference for exploring non-noble metal composite materials and demonstrated great potential in photocatalytic. [Display omitted] • The 3D nanostructured dodecahedron ZIF-67 is prepared. • Sm 2 WO 6 /ZIF-67 is prepared through the in situ growth method. • Sm 2 WO 6 /ZIF-67 photocatalytic hydrogen production activity is improved. • A S-scheme heterojunction is constructed for photocatalysis. • The photocatalysis is enhanced by adjusting the direction of electron transfer. [ABSTRACT FROM AUTHOR]

Promoting the separation of electron and hole plays an important role in photocatalytic hydrogen production. However, single semiconductor materials cannot fully realize their potential due to the rapid recombination of photogenerated carriers. Therefore, in this experiment, a new photocatalyst ZnIn 2 S 4 /NiMoO 4 was prepared by using an electrostatic self-assembly method, which greatly improved the electron-hole recombination phenomenon. After 5 h reaction under visible light irradiation, ZIS/NMO-3 composite catalyst prepared in ethanol showed the best photocatalytic activity, and the hydrogen evolution capacity reached 173.09 μmol. The hydrogen evolution capacity of ZIS/NMO-3 was 2.47 and 25.83 times that of short rod-like NiMoO 4 and microflower-like spherical ZnIn 2 S 4 , respectively. Through some physical characterization and electrochemical experiments, it can be seen that NiMoO 4 and ZnIn 2 S 4 have good composability. Meanwhile, the composite catalyst ZnIn 2 S 4 /NiMoO 4 -3 has high current response characteristics. It can be seen from the fluorescence emission spectra that the composite catalyst presents the lowest peak value, which indicates that ZIS/NMO-3 can effectively inhibit the recombination of photogenerated electrons and holes. When ZnIn 2 S 4 is loaded on NiMoO 4 , the separation of photogenerated carrier will be accelerated due to the formation of heterojunction, thus improving the photocatalytic activity. At the same time, the large specific surface area will also provide more abundant active sites for the composite catalyst, which provides a good condition for photocatalytic hydrogen production. This work provides an efficient, uncomplicated and feasible method for the synthesis of ZIS/NMO-3 composite catalyst with excellent properties. • The heterojunction between ZnIn 2 S 4 and NiMoO 4 has good stability. • Dispersion of ZnIn 2 S 4 on NiMoO 4 is important for the HER activity. • Discussion on electron transfer path and hydrogen evolution mechanism. • High-efficiency hydrogen evolution is realized through ZnIn 2 S 4 /NiMoO 4 heterojunction. [ABSTRACT FROM AUTHOR]

The heterojunction construction can effectively regulate the carrier transport pathway. Ag 2 Mo 2 O 7 /CoMoO 4 composite molybdate material was successfully synthesized by one step hydrothermal calcination method. The preparation method makes the contact of the two molybdate salts closer, forming a stable S-scheme heterojunction. Then SnS 2 was added under physical agitation to improve the mobility of photogenerated carriers. The excellent structure of the ternary composite catalyst was proved by morphology and element analysis. The electron transfer mechanism of the S-scheme heterojunction was studied by photoelectric chemical test and spectral analysis. Because of the successful construction of S-scheme heterojunction and the introduction of sensitizer SnS 2 , the composite catalyst showed excellent hydrogen evolution performance (1599 μmol·g−1·h−1). This is because the S-scheme heterojunction and the sensitizer cooperatively promote the electron accumulation at the conduction band of CoMoO 4. This work will provide a new strategy for molybdate in a heterojunction construction scheme. The S-scheme heterojunction can effectively regulate the carrier transport path and elevate the semiconductor hydrogen evolution material to a new height. In this study, Ag 2 Mo 2 O 7 /CoMoO 4 composite molybdate material was synthesized on the basis of hydrothermal and calcination and then doped with SnS 2 as a sensitizer. The ternary composite catalyst Ag 2 Mo 2 O 7 /CoMoO 4 /SnS 2 shows excellent hydrogen evolution performance under the dual effect of S-scheme heterojunction and sensitizer. The hydrogen evolution rate is as high as 1599 μmol g−1 h−1, which is attributed to the retarding of carrier recombination by the heterojunction of S scheme and the accumulation of photo-generated electrons by the sensitizer. [Display omitted] • Molybdate composite was synthesized by hydrothermal and calcination. • A novel S-scheme heterojunction was constructed with molybdate. • Adequate characterization supports the excellent performance of the system. • S-scheme heterojunction and sensitizer cooperate to promote hydrogen evolution. • The possible mechanism of improving photocatalytic activity was elucidated. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnO/Cu/Cu 2 O catalysts with different Cu contents at the interface are prepared. • Both Schottky junctions and P-N heterojunctions are generated in ZnO/Cu/Cu 2 O catalysts. • ZnO/Cu/Cu 2 O with an optimal portion of Cu exhibits higher catalytic activity. • Schottky heterojunctions can promote electron transfer at P-N heterojunctions. Forming heterojunctions in catalysts is an effective way to modulate their electronic structures and catalytic performance. However, this strategy is rarely applied to thermal catalysis. Herein, the ZnO/Cu/Cu 2 O catalysts with different metallic Cu contents and both Schottky and P-N heterojunctions were prepared by simply reducing ZnO/Cu 2 O with CO and investigated for their electronic effects on the catalytic property in the Rochow-Müller reaction. The ZnO/Cu/Cu 2 O catalyst with an optimal content of metallic Cu exhibited a much-enhanced catalytic activity towards the targeted product of dimethyldichlorosilane. Detailed characterizations and theoretical calculations showed that the formation of the Schottky junction between Cu and ZnO promotes electron transfer at the P-N heterojunction between Cu 2 O and ZnO, leading to enhanced reduction of Cu+ into active Cu atoms and the ultimate formation of the Cu 3 Si active phase. This work provides a new fundamental understanding of the electron structure effect on catalysis and a strategy to design highly efficient heterogeneous catalysts for the Rochow-Müller reaction. [ABSTRACT FROM AUTHOR]

The hydrothermal preparation of NiCo 2 S 4 /ZnIn 2 S 4 photocatalysts with different mass ratios is studied. Ni-cobalt bimetallic sulfide nanosheets are grown on zinc-indium bimetallic sulfide to form a compact heterojunction. First, both NiCo 2 S 4 and ZnIn 2 S 4 exhibit N-type semiconductor characteristics, a heterojunction formed by both can reduce the surface reaction energy barrier and use its synergy, strengthening the charge self-diffusion between the two semiconductors, it means the formation of a strong electric field. From the electron transfer path and band structure, NiCo 2 S 4 /ZnIn 2 S 4 has S-scheme heterojunction characteristics. NiCo 2 S 4 is a reducing photocatalyst (RP), and ZnIn 2 S 4 is an oxidative photocatalyst (OP). Under the action of built-in electric field (BIEF), strong photogenic electrons and holes exist in CB of RP (NiCo 2 S 4) and VB of OP (ZnIn 2 S 4). Thus, the overall redox capacity of the NiCo 2 S 4 /ZnIn 2 S 4 heterojunction is enhanced. Using visible light, the composite material can be used for photocatalytic hydrogen production. It is further shown that the composite material has a good effect in photocatalytic hydrogen production under the sensitizer eosin Y (EY) system. The optimal hydrogen production is about 221.75 μmol when the mass ratios of NiCo 2 S 4 /ZnIn 2 S 4 is 20%, and the photocatalytic activity of the composite is about 47 times that of ZnIn 2 S 4. Notably, the stability of the composites is the better. A reasonable photo-catalytic mechanism is proposed based on the band gap and photoelectrochemical properties of heterojunction. • Nanosheets NiCo 2 S 4 innovatively decorated on globular structure ZnIn 2 S 4 form S-scheme heterojunction. • The morphology of nanosheets NiCo 2 S 4 is innovative in the field of NiCo 2 S 4 /ZnIn 2 S 4 photocatalysis. • The heterojunction can short transfer route to promote electron efficient transport. • Dispersion of NiCo 2 S 4 on ZnIn 2 S 4 is important for the heterojunction HER activity and stability. [ABSTRACT FROM AUTHOR]

In the process of photocatalysis, semiconductor materials generate photogenerated electrons and photogenerated holes when excited by sunlight, so as to participate in the process of photocatalytic decomposition of water to produce hydrogen. In this work, under the combined action of ultrasonic and electrostatic forces, two semiconductors are successfully coupled through electrostatic self-assembly to effectively avoid the serious phenomenon of sulfide photocorrosion. Through electrochemical and fluorescence characterization experiments, it is confirmed that ZnCo2O4/CdS can accelerate the generation and transmission rates of photogenerated carriers. ZnCo2O4/CdS greatly increased the activity of the catalyst under simulated sunlight irradiation. With good photocatalytic activity, the hydrogen yield reached 80.71 mmol g−1 within 5 hours, far superior to those of Co3O4/CdS and ZnO/CdS. The relative values of the work functions of ZnCo2O4(311) and CdS(110) were calculated by DFT. Combined with the position of the conduction band, it was concluded that a new S-scheme induced by an internal electric field was formed at the ZCO/CS-25% contact interface, thus improving the photocatalytic activity. [ABSTRACT FROM AUTHOR]

A Bi2WO6/BiOBr/RGO (BWO/BOB/RGO) composite photocatalyst with a Z-type heterojunction was prepared by a simple one-pot hydrothermal method, and the micro-morphology and physicochemical properties of the prepared samples were characterized. After reacting under visible light for 120 min, the degradation rate of 20 mg L−1 norfloxacin (NOR) by BWO/BOB/RGO was 95.12%, and the kinetic constant of the reaction was 6.42 times higher than that of pure BiOBr. Furthermore, BWO/BOB/RGO also shows good recycling stability and universality. The characterization results show that the improvement of the photocatalytic performance of the catalyst is mainly due to the heterojunction formed between Bi2WO6, RGO and BiOBr, which enhances the visible light absorption ability, accelerates the photogenerated electron migration and improves the electron–hole pair separation efficiency. The introduction of Bi2WO6 and RGO into the catalyst also increased its specific surface area and made it have more surface-active sites. The results of radical capture experiments showed that ˙O2− and h+ played an important role in the BWO/BOB/RGO reaction system, and the intermediate products and possible degradation pathways of the system were detected and analyzed. Furthermore, the electron transfer mechanism of the Z-type heterojunction using RGO as an electron transport medium and the mechanism of photocatalytic degradation of norfloxacin were proposed. [ABSTRACT FROM AUTHOR]

Photocatalysis is one of the most promising methods to solve the problems of solar energy conversion and sustainable fuel production. Among them, the semiconductor electronic transition to produce hydrogen is the most critical research topic in the field of photocatalysis. ZnS and Ag2Mo2O7 monomers were prepared by the hydrothermal method. The S-scheme heterojunction was formed by electrostatic adsorption of the two materials. The S-scheme heterojunction can improve the separation rate of photogenerated carriers through the built-in electric field so that the hydrogen production rate of the system can reach a maximum of 871.9 μmol g−1 h−1. The system showed a good photoelectric response according to UV-Vis DRS and electrochemistry studies and excellent hydrogen evolution performance. In this study a DFT simulation of the heterojunction interface formed by the system was also carried out, and the relative size of the surface work function indicated the transfer direction and path of electrons. [ABSTRACT FROM AUTHOR]

The study of environmentally friendly semiconductor photocatalysts has important practical significance for efficient photocatalytic hydrogen evolution. In this experiment, type II heterojunction NiCo-LDH/CeO2 was prepared by in situ loading, and the NiCo-LDH/CeO2 catalyst showed good activity under simulated sunlight irradiation. Under simulated visible light irradiation, its hydrogen production rate reached 2.7 mmol h−1 g−1, which was higher than that of NiCo-LDH (0.86 mmol h−1 g−1). Through a series of characterization data, it can be concluded that the heterojunction successfully constructed by the close contact between NiCo-LDH and CeO2 accelerates the separation of photogenerated electrons and holes and can effectively inhibit the recombination of the two so that more electrons are involved in the hydrogen evolution reaction. The material has good interfacial charge transfer performance, which improves the photocatalytic performance. This work can provide an effective method for the research and development of NiCo-LDH. [ABSTRACT FROM AUTHOR]

Graphdiyne (GDY), an innovative 2D carbon material, has received substantial interest for its superior conductivity, adaptable electronic configuration, and unique electron-electron transfer amplification features. CWN (CoWO 4 /NC) and GDY were used to prepare CWN/GDY via the electrostatic self-assembly method. The hydrogen production of CWN/GDY-1:1 was tangibly increased compared with that of CWN and GDY alone, and reached 3455 μmol∙ g−1∙ h−1. The photocatalytic hydrogen production of CWN/GDY-1:1 was 3.37 times that of CWN. The existence of this complex was confirmed by the analysis of structure, morphology, and elemental composition. CWN and GDY have the necessary conditions to produce heterojunctions since SEM and TEM images show that they are in extremely close contact. The electron transfer between the two can be found by XPS. Electrons are transferred from the CB of CWN to the CB of GDY for the synthesis of hydrogen, while holes are transferred at different rates from the VB of CWN to the VB of GDY. By creating a heterojunction, photogenerated electrons can travel faster and photosynthetic electrons cannot attach to holes. To sum up, the CWN/GDY-1:1 composite exhibits strong photocatalytic activity and stability, which provides valuable guidelines for tungstate composites and has great application potential in photocatalysis. [Display omitted] • The catalyst of GDY and CWN was prepared by electrostatic self-assembly. • Semiconductor-driven photocatalysts are used in the field of photocatalysts. • The possible mechanism of improving photocatalytic activity was elucidated. [ABSTRACT FROM AUTHOR]

The room-temperature mechanochemical synthesis method was employed to fabricate the AgCl@Ag-NPs and AgCl@AgNPs/TiO2 composite photocatalysts efficiently. The polyethylene glycol 400 was introduced to adjust the microstructure and layout of nanoparticles to form a large number of heterojunctions or even heterojunction chains between Ag-NPs and AgCl/TiO2. The surface plasmon resonance effect of metallic silver nanoparticle extends the absorption spectrum of composite to the visible region. And the metal–semiconductor heterojunction configuration enables the effective separation of electron–hole pairs to endow them strong catalytic activity for degradation of oxytetracycline under man-made natural light irradiation and, meanwhile, suppresses the bleaching of AgCl to give them good microstructural stability and photocatalytic reusability. In the process of photodegradation of oxytetracycline, AgCl@AgNPs/TiO2 showed the higher catalytic efficiency through fuller synergy compared to AgCl@AgNPs. This work lays out a green degradation strategy for antibiotics in the ecological environment. [ABSTRACT FROM AUTHOR]

Constructing suitable heterojunction with interface engineering has been an effective way to boost charge separation of semiconductors, thus providing improved photocatalytic ability. In this work, a novel bimetallic framework (ZnCd-MOF) was prepared to construct heterojunction with Ag3PO4. The ZnCd-MOF nanosheets were dispersed around Ag3PO4 particles with a close interface; as a result, the interface photo-charge separation was enhanced, and more photogenerated holes can be concentrated on the Ag3PO4 for realizing a higher photocatalytic activity. The obtained ZnCd-MOF/Ag3PO4 composites exhibited higher photocatalytic oxygen production activity than that of pure Ag3PO4. Furthermore, when the content of ZnCd-MOF in the composite increased from 1 to 10 wt%, the oxygen production increased from 1399 to 2458 µmol g−1 under simulated sunlight irradiation. This work provides a new way to design high-efficiency Ag3PO4-based heterojunction photocatalyst via taking full advantage of the interface engineering in the composite together with providing abundant active sites for photocatalytic oxygen production. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production is the most promising solution to environmental pollution and energy crisis. A reasonable construction of heterojunction is one of the common methods to improve photocatalytic hydrogen production. The nanosheet MgAl‐LDH and Co3O4 form a sea urchin‐like MgAl‐LDH/Co3O4 p‐n heterojunction by electrostatic self‐assembly. Under the irradiation of light, the hydrogen yield of the composite catalyst will reach 120 μmol in 5 h. Compared with Co3O4, it is six times higher. This is because, after the successful coupling of the two semiconductors, an internal electric field is generated on the surface of the material, which accelerated the flow of photogenerated carriers, thus improving the photocatalytic performance of the material. XRD, SEM, FTIR, and TEM confirm the successful synthesis of the composite catalyst. In XPS analysis, strong interaction between electrons is found. In addition, the photoluminescence spectra and electrochemical analysis are used to compare the photogenic electron production and transfer rates of different catalysts. Based on the above analysis combined with UV–vis DRS diffuse reflection spectroscopy and BET characterization, a possible hydrogen evolution principle is proposed and analyzed. [ABSTRACT FROM AUTHOR]

Based on the structural characteristics of bimetallic phosphates, the rod‐like NiCoP/NiMoO4 heterojunction composite catalyst is successfully synthesized by hydrothermal method, which realizes the rapid transfer of photogenerated carriers across the heterojunction interface, thereby improving the performance of photocatalytic decomposition of water to produce hydrogen. Through photocatalytic experiments, the hydrogen evolution rate of the NiCoP/NiMoO4 is 61.4 μmol h−1, which is 2.93 times that of pure NiMoO4. Further study on the catalyst shows that this structure could greatly improve the utilization rate of sensitizer and hole sacrifice agent in the dye sensitization system, and the rate of photon‐generated carrier separation and transfer is significantly improved to achieve a good hydrogen evolution effect. [ABSTRACT FROM AUTHOR]

The development of efficient photocatalysts is a very interesting topic for sustainable hydrogen production using solar energy. In this paper, Mn 0.2 Cd 0.8 S was loaded on CoMoO 4 nanorods by in-situ solvothermal method. Through morphological control, two rod-shaped elemental materials were loaded in situ to construct a composite with a ball shaped bouquet structure. The Mn 0.2 Cd 0.8 S/CoMoO 4 photocatalyst with enriched oxygen vacancies was synthesized by high-temperature annealing. It is worth noting that by constructing an heterojunction, the Mn 0.2 Cd 0.8 S/CoMoO 4 photocatalyst exhibits high catalytic activity and stability. The optimal H 2 production rate of Mn 0.2 Cd 0.8 S/CoMoO 4 was 7.04 mmol·g−1·h−1. Surprisingly, the hydrogen production rate of the composite was 35.88 times that of CoMoO 4. Density functional theory (DFT) calculations showed that Mn 0.2 Cd 0.8 S/CoMoO 4 has electron attraction ability and strong conductivity. X-ray photoelectron spectroscopy (XPS) confirmed the charge transfer path of the heterojunction between Mn 0.2 Cd 0.8 S and CoMoO 4 , which greatly promoted the spatial charge separation. This work provides a reference for combining heterojunction design with defect engineering to achieve efficient conversion of solar energy to chemical energy. • Mn 0.2 Cd 0.8 S was loaded on CoMoO 4 nanorods by in-situ solvothermal method. • Design composite catalyst from the two aspects of morphology and band structure. • Mn 0.2 Cd 0.8 S/CoMoO 4 with enriched oxygen vacancies was synthesized. • The recombination of photo-generated carriers was effectively suppressed. [ABSTRACT FROM AUTHOR]

In the field of photocatalysis, the recombination of photogenerated holes and electrons is still an urgent problem to be solved. Among many measures, constructing heterojunction is one of the commonly used methods to adjust the carrier transfer path and accelerate the electron transfer. In this paper, Fe2O3/NiS p–n heterojunction composite catalyst was synthesized by solvothermal method. Through XRD, SEM and XPS characterization and analysis, it was found that the composite catalyst was composed of NiS nanoparticles and hexagonal Fe2O3 nanosheets. The specific surface area test results showed that Fe2O3/NiS had a larger specific surface area, which could provide more active sites for the H2 production reaction. By adjusting the ratio between Fe2O3 and NiS, the optimal composite photocatalyst was obtained. The hydrogen production rate reached 5.82 mmol g−1 h−1, which was 58.2× that of single Fe2O3 and 2.7× that of single NiS. The NiS p-type semiconductor and Fe2O3n-type semiconductor were successfully coupled. Under the action of the p–n heterojunction interface and the built-in electric field, the photogenerated electrons and holes of the composite catalyst could be quickly transferred and separated. This result was also confirmed by a series of characterizations such as photoluminescence spectrum and photoelectrochemical experiments. Fe2O3 and NiS formed p–n heterojunctions, and the mixed interface structure between them provided a new hydrogen-producing active center for each. Moreover, the construction of p–n heterojunction promoted the separation of electrons (e−) and holes (h+), so that Fe2O3/NiS exhibited excellent hydrogen evolution performance. [ABSTRACT FROM AUTHOR]

The construction of heterojunctions can effectively improve the electron transport rate and photocatalytic activity. In this work, nanoflower-like S-scheme heterojunction MoS2/NiAl-LDH was successfully synthesized. The results indicated that the hydrogen yield of the MoS2/NiAl-LDH composite catalyst reached 229.5 μmol in 5 hours under visible light irradiation by adjusting the pH value of the sacrificial agent and the amount of eosin. The crystal structure and morphological characteristics of the composite were analyzed by XRD, SEM and TEM. The visible light response degree and charge separation and transfer rates of photogenerated carriers of the composite were analyzed by UV-Vis DRS, PL and electrochemistry. The electronic transfer path was also analyzed by XPS. The construction of S-scheme heterojunctions can realize effective separation of electron–hole pairs and ensure that the photo-induced carriers with the strongest redox ability can be retained to participate in the photocatalytic reaction. In addition, the feasible mechanism of photocatalytic hydrogen evolution is given. This work will provide different insights into the enhancement of hydrogen evolution by heterojunctions formed by binary semiconductors. [ABSTRACT FROM AUTHOR]

In this paper, NiCo2S4 was coated on the surface of WS2 of a 1T/2H mixed phase by a two-step hydrothermal method to form an in situ core–shell structure. The unique S-scheme heterojunction of the NiCo2S4@WS2 core–shell composite photocatalyst improved the easy recombination of carriers caused by the narrow band gap of NiCo2S4 and WS2, and improved the photocatalytic hydrogen production performance. The loading ratio of NiCo2S4@WS2, the addition of Eosin Y, and the pH value of TEOA were optimized. Under the optimal conditions, the hydrogen production rate reached 5.814 mmol g−1 h−1, which is about 8.55 times and 3.35 times the hydrogen evolution rates of NiCo2S4 and WS2, respectively. The composite catalyst exhibits excellent charge separation efficiency in photoelectrochemistry, PL and BET tests, carrier transport rate and large specific surface area that can provide more active sites, which are the main factors for the improvement of the hydrogen evolution performance. This paper demonstrates new design strategies to drive efficient photocatalytic hydrogen production by building in situ core–shell structures and optimizing the carrier transport paths, which will yield new insights. [ABSTRACT FROM AUTHOR]

Bimetallic oxides have attracted extensive attention due to their excellent photocatalytic properties. Co2NiO4 has good electrical activity which can effectively regulate the distribution of charge. The scanning electron microscope and transmission electron microscope images of Co2NiO4 showed two-dimensional uniform lamellar morphology. This kind of morphology could provide a larger specific surface area, which was conducive to improving photocatalytic water decomposing and hydrogen evolution. In addition, we combined Co2NiO4 with NiWO4 to improve the conductivity of Co2NiO4 and the position of Fermi energy level, forming a p-n-type heterojunction, effectively promoting the interface charge transfer through the internal electric field, and inhibiting the electron–hole pair recombination. The photocatalytic hydrogen production of CN/NW-3 in the sensitized system reached 341.83 μmol for 5 h, which was 19 times that of pure Co2NiO4. At the same time, UV–Vis diffuse reflection and Mott–Schottky curve were used to further determine the conduction band (CB) and valence band (VB) positions of Co2NiO4 and NiWO4, which formed a charge transport path with higher separation and transfer efficiency. This work highlights the high-efficient photocatalytic hydrogen production performance of CN/NW p-n heterojunction. Co2NiO4 and NiWO4 form p-n heterojunction, and the synergy between them provides a new hydrogen-producing active center for each. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) molybdenum disulfide (MoS2) field-effect transistor (FET) gated by negative capacitance (NC) is a promising architecture to overcome the thermionic limit and thus reduce device consumption. Here, top-gated MoS2 NCFETs have been prepared by transferring a mica flake on MoS2 channel to form a van der Waals heterojunction interface, together with a ferroelectric HfZrO2 (HZO) deposited on mica. Stable NC effects are demonstrated for MoS2 NCFETs. The MoS2 NCFETs integrated with mica/HZO gate stack provide competitive electrical characteristics when they are applied with a gate voltage sweep-width in the range of 1−3 V and a sweep-rate from 0.01 to 0.2 V s−1, including steep-slope of sub 60 mV dec−1 in four orders of magnitude of drain current, on/off current ratio over 106, and small hysteresis-width less than 50 mV. Outstanding performance should be ascribed to damage-free properties of mica/MoS2 van der Waals interface and capacitance matching between the HZO ferroelectric and mica dielectric. The results confirm the promising nature of mica/HZO gate stack and potential applications for future electronics. [ABSTRACT FROM AUTHOR]

In the field of photocatalysis, building a heterojunction is an effective way to promote electron transfer and enhance the reducibility of electrons. Herein, the S‐scheme heterojunction photocatalyst (CoS2/Zn0.5Cd0.5S) of CoS2 nanospheres modified Zn0.5Cd0.5S solid solution was synthesized and studied. The H2 evolution rate of the composite catalyst reached 25.15 mmol g−1 h−1, which was 3.26 times that of single Zn0.5Cd0.5S, whereas pure CoS2 showed almost no hydrogen production activity. Moreover, CoS2/Zn0.5Cd0.5S had excellent stability and the hydrogen production rate after six cycles of experiments only dropped by 6.19 %. In addition, photoluminescence spectroscopy and photoelectrochemical experiments had effectively proved that the photogenerated carrier transfer rate of CoS2/Zn0.5Cd0.5S was better than CoS2 or Zn0.5Cd0.5S single catalyst. In this study, the synthesized CoS2 and Zn0.5Cd0.5S were both n‐type semiconductors. After close contact, they followed an S‐scheme heterojunction electron transfer mechanism, which not only promoted the separation of their respective holes and electrons, but also retained a stronger reduction potential, thus promoting the reduction of H+ protons in photocatalytic experiments. In short, this work provided a new basis for the construction of S‐scheme heterojunction in addition to being used for photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Ni-based nanomaterials have attracted extensive attention as photocatalysts thanks to their high photocatalytic activity and non-toxicity. In this study, a novel visible-light-induced photocatalyst CuMn-LDO/NiS (CMS) was successfully synthesized with high yield and nanostructure. The crystal structure, chemical composition and morphology of the catalysts were analyzed by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). The photoelectric properties of the catalysts were analyzed by photoluminescence (PL) spectroscopy, UV-vis diffuse reflectance spectroscopy and electrochemical measurement. The photocatalytic performance of CMS p–p heterojunction was measured under the condition of light. The results showed that when the content of CuMn-LDO was 40%, hydrogen evolution reached 194 μmol, which is about 10 times that of pure CuMn-LDO. The enhanced photocatalytic activity of composite CMS was due to the formation of a p–p heterojunction, which inhibits the recombination of e− and h+, and improves the separation ability of photogenerated carriers. [ABSTRACT FROM AUTHOR]

A novel red phosphorus/nickel cobalt layered double hydroxide (RP/NiCo-LDH) heterojunction was successfully prepared and exhibited an excellent photocatalytic performance for hydrogen evolution. The formation of an S-scheme between purified RP and the NiCo–LDH effectively promoted the generation of an electric field at the interface between RP and the NiCo-LDH. The existence of an internal electric field can promote the migration of photoexcited carriers from the conduction band of pure RP to the valence band of the NiCo-LDH, thus effectively inhibiting the recombination efficiency of electron/hole pairs. Under simulated visible-light irradiation, the hydrogen evolution activity of the 70 wt% NiCo-LDH composite catalyst RP/NiCo-LDH reached 32.8 mmol g−1 at 5 h, which was 6.41 times that of pure NiCo-LDH. The RP/NiCo-LDH composite photocatalyst was characterized using a series of characterization techniques. Among them, UV absorption spectra, fluorescence and photoelectrochemical experiments showed that the absorption rate and the electron-transfer rate of the RP/NiCo-LDH composite catalyst were significantly higher than that of the pure RP and NiCo-LDH. Therefore, RP/NiCo-LDH composite photocatalysts open up a new route for the development of non-noble metal photocatalysts. [ABSTRACT FROM AUTHOR]

A novel composite photocatalyst RP/BP/Co-MOF was prepared for highly efficient photocatalytic hydrogen evolution. Metal–organic frameworks Co-MOF was used as an electron transfer medium in composite photocatalyst, it accelerated the electron transfer rate between red phosphorus and black phosphorus. It had played an important role in RP/BP Z-scheme heterojunction system. Under simulated visible light exposure, the hydrogen production amount of the composite photocatalyst RP/BP/Co-MOF was 632.4 μmol in 5 h, which was 44.82 times as much as RP/BP flake. At the same time, a series of characterization of the composite photocatalyst was carried out. The results of photoluminescent spectroscopy and electrochemical measurements showed that the combination of RP/BP Z-scheme heterojunction and 2D sheet Co-MOF could effectively inhibit the recombination of photogenerated carriers, promote the transfer of electrons and improve the photocatalytic activity of the composite photocatalyst. This work provided an important way to develop a low-cost photocatalyst with high hydrogen yield. Red/Black phosphorus Z-Scheme heterogeneous junction modulated by Co-MOF for enhanced photocatalytic hydrogen evolution. The enlarged part shows the structure structure of Co-MOF. C: black; N: light blue; Co: purple. Hydrogen atoms are omitted for clarity. [ABSTRACT FROM AUTHOR]

Y‐TiO2/5A/NiFe2O4 composite was prepared by hydrothermal and sol‐gel method. The structure, morphology and optical properties of the composite were investigated by XRD, FT‐IR, XPS, SEM, UV‐vis DRS and so on. Compared with 5A, TiO2, TiO2/5A and Y‐TiO2/5A, the photocatalytic properties of Y‐TiO2/5A/NiFe2O4 was enhanced and the removal rate of norfloxacin can reach the highest 96.55 % under visible light for 60 min. Moreover, the photocatalyst still has good photocatalytic performance after three cycles of use. This improvement is mainly attributed to two factors. On the one hand, the doping of Y brings impurity level to TiO2, which broadens the spectral response range of the photocatalyst to the visible region. On the other hand, NiFe2O4 forms Z‐scheme heterojunction with TiO2, which enables the photogenerated carriers to be separated effectively through the interface of heterojunction, thus improving the performance of the photocatalyst. Moreover, the photocatalyst still has a good removal rate for several other antibiotics. Finally, a possible electron transfer mechanism is proposed based on characterization and active species capture experiments. [ABSTRACT FROM AUTHOR]

Due to the poor photocatalytic hydrogen evolution ability of pure CdS, we need to develop a photocatalytic hydrogen evolution catalyst with high activity and no precious metal doping. Therefore, in this article, we used a simple hydrothermal synthesis of CdS nanoparticles, using water as a carrier, loading a small amount of amorphous CoS, by changing the loading ratio of amorphous CoS, synthesized TYPE–II type heterojunction composite catalyst CCS. The successful synthesis of the composite catalyst CCS was verified by XRD, SEM and other characterization methods. UV–vis, PL and other characterization showed that the supported amorphous CoS could significantly improve the photocatalytic activity of CdS, and the photochemical detection also showed that the performance of composite catalyst CCS was better than that of pure CdS. Using Na2S and Na2SO3 mixed solution as electron sacrificial agent, the hydrogen production performance of CCS composite catalyst was determined through hydrogen evolution experiment and cyclic stability experiment. It was found that the sacrificial agent had a great promotion effect on the hydrogen production performance of photocatalyst. It was found that the hydrogen production rate of the composite catalyst could reach 2.01 mmol·g−1·h−1, which was 6.3 times of the pure CdS. This study offers a novel approach for the design of amorphous–based nanostructures as efficient hydrogen evolution cocatalysts. First, CdS are excited by light, consuming S2− and SO32− ions in the sacrificial agent, generating a large number of electrons and holes. Due to the energy difference between the conducting band (CB) of CdS and amorphous CoS, the electrons are transferred from the surface of CdS to the conducting band (CB) of amorphous CoS, while the electrons obtained from water and H+ in the sacrificial agent are reduced to H2. The amorphous CoS is used as the transfer medium of electron acceptor, and the synergistic effect between heterojunctions is used to improve the charge separation efficiency and electron transfer rate. Therefore, the photocatalytic hydrogen production effect of the composite catalyst CCS–7 has been greatly improved. [ABSTRACT FROM AUTHOR]

The 2D nanosheet Sm2MoO6 is mounted on a bulk 3D NiS to form a durian‐like 2D/3D heterojunction photocatalyst, and the photocatalytic activity is studied. The photocatalytic activity of the optimal composite catalyst is 8.3 times higher than that of NiS. Compared with Sm2MoO6, it is increased by 186.7 times. On the one hand, it may be attributed to the assembly of 2D nanosheets onto a massive 3D structure, effectively preventing the problem of stacking due to high surface energy and interlayer van der Waals attraction. The specific surface area of the catalyst is expanded to provide more active sites, which facilitates contact of the catalyst with the sensitizer and the sacrificial agent. On the other hand, Sm2MoO6 as a rare earth cocatalyst, the activation energy required for the surface reaction can be lowered, and the electron–hole separation ability can be improved. [ABSTRACT FROM AUTHOR]

The exploration of Z-scheme heterojunction photocatalysts is considered crucial to improve the efficiency of photocatalytic hydrogen evolution. In this work, ZSN with a Z-scheme heterojunction is prepared by a two-step hydrothermal method. Through the study of the surface morphology, crystallization properties, surface chemistry and optical properties of the photocatalyst, it is known that the ZSN heterojunction can improve the visible light capture ability, prolong the service life of charges, improve the efficiency of charge separation, and improve the photocatalytic performance. Under visible light irradiation, the amount of hydrogen evolution of the optimized 2-ZSN is 74 μmol, 37 times that of the pure ZnS (2 μmol). The results of photoluminescence (PL), ultraviolet-visible (UV-Visible) and electrochemical techniques show that the Z-scheme mechanism is advantageous to the separation of photogenic carriers as well as the hole transfer and separation. This work provides a reliable strategy for constructing efficient Z-scheme heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

Semiconductor heterojunction has been regarded as one of the most promising strategies to produce efficient photocatalysts, which construction can be beneficial to accelerate the separation of photo-induced charge carriers for boosting photocatalytic H 2 production. Herein, noble-metal-free MoS 2 was adopted as a co-catalyst to construct a ternary Bi 2 S 3 /MoS 2 /P25 heterojunction for boosting electrons transfer and further evaluating for H 2 production from water under solar irradiation. Due to the synergistic effects of the co-catalyst and heterojunction in the Bi 2 S 3 /MoS 2 /P25 system, the optimal MoS 2 /P25/Bi 2 S 3 sample provides the excellent photocatalytic activity of H 2 evolution rate (13.0 mmol g−1 h−1), which can be ascribed to the positive synergetic effects of improved charge transfer and efficient separation of the light-induced charge carriers of MoS 2 /P25/Bi 2 S 3 arose from the dual-channel charges transfer path. By taking full advantage of ternary heterojunction and co-catalyst for promoting H 2 production, this work guarantees insights into the low-cost, large-scale production of commercial TiO 2 -based ternary composite materials applied in solar photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Overall dye-sensitized photocatalytic HER system based on g-C 3 N 4 and 2D Co MOF doped by Sm achieved effective photocatalytic H 2 evolution. • An overall dye-sensitized system was constructed for efficient photocatalytic HER. • 2D Co MOF and protonated g-C 3 N 4 formed a 2D/2D heterojunction. • Protonated g-C 3 N 4 preferentially adsorbed EY molecules. • Sm element doping 2D Co MOF further improved carrier separation. A dye-sensitive photocatalytic H 2 evolution reaction (HER) system with photogenerated carrier directed conduction was constructed. The protonated g-C 3 N 4 combines with the sheet-like Co MOF to form a 2D/2D heterojunction via electrostatic self-assembly. The protonated g-C 3 N 4 and 2D Co-MOF directionally adsorb Eosin Y (EY) and triethanolamine (TEOA) molecules through hydrogen bond and complexation to achieve a whole photocatalytic system. The integral structure effectively facilitates the utilization of dye sensitizer and hole sacrificial agent to achieve the effective and stable photocatalytic H 2 evolution capacity. The photocatalytic hydrogen evolution rate of g-C 3 N 4 after protonation is 1.88 times as high as that of the original g-C 3 N 4. On the basis of 2D/2D heterojunction, Co MOF is doped with rare earth element Sm. The 4f electrons and the difference valences (Sm3+ and Co2+) further suppress the reorganization of photogenerated excitons to achieve highly efficient photocatalytic HER. The directional coupling of sensitizer and electron sacrificial agent combined with rare earth element doping makes the photocatalytic HER rate of the composite material reached 73.42 μmol.h−1 within 5 h under simulated sunlight. [ABSTRACT FROM AUTHOR]

With the development of research on the photocatalytic water splitting and hydrogen (H 2) precipitation, cobalt ferrite and molybdate have begun to appear as catalysts for the study of photocatalytic hydrogen precipitation. In this paper, the p-n heterojunction CoFe 2 O 4 /NiMoO 4 (CFO/NMO) is prepared by hydrothermal method. The constructed p-n type (type Ⅱ) heterojunction CFO/NMO has the highest hydrogen evolution (Eosin Y as a sensitizer), which is 7.39 times and 1.95 times that of elemental CFO and NMO, respectively. After the CFO and NMO form a heterojunction, a built-in electric field is formed inside to effectively separate the photogenerated carriers. At the same time, the dense interface of the heterojunction also promotes the transfer of photogenerated carriers and promotes the reduction of H+ protons on this catalyst surface. In short, this work provides more possibilities for the field of photocatalytic hydrogen evolution from molybdate and cobalt ferrite compounds. Image 1 • High-efficiency hydrogen evolution is realized through CoFe 2 O 4 /NiMoO 4 heterojunction composite material. • The synergistic effect of magnetic CoFe 2 O 4 and NiMoO 4 improves the photocatalytic hydrogen evolution activity. • Experimental characterization to verify the photocatalytic mechanism of p-n heterojunction. [ABSTRACT FROM AUTHOR]

One of the most effective methods to improve electron-transfer efficiency and photocatalytic reaction activity is to construct a photocatalyst with a heterojunction interface. Herein, a WO3/CoS2 n–n heterojunction composite catalyst was synthesized, and used in photocatalytic hydrogen evolution, and was optimized by adjusting the pH of the triethanolamine solution, the amount of Eosin Y added, and the content of WO3 in the composite catalyst. After 5 h of photocatalytic reaction, WO3/CoS2 (WCS-2) had a H2 production of 221.15 μmol, which was 80.41 times that of single WO3 and 2.17 times that of CoS2, and had good stability. XRD, SEM, TEM, and XPS characterization results indicated that WO3/CoS2 was successfully prepared. Fluorescence test and electrochemical test results showed that the WO3/CoS2 catalyst had a higher photoelectron transfer efficiency. Finally, it is pointed out that WO3/CoS2 enhanced the photocatalytic activity, which may be due to the electron migration of WO3 and CoS2 following the Z-scheme mechanism. This work presents a new idea for constructing n–n heterojunction to enhance the activity in photocatalytic hydrogen production. [ABSTRACT FROM AUTHOR]

Research into catalytic materials that convert light energy into chemical energy by decomposing water still faces great difficulties. CuNi2S4 has attracted public attention due to its unique morphology; however, its high electron–hole recombination rate and weak charge separation efficiency limit its use in the field of catalysis. Herein, CoWO4 material is synthesized in situ on a CuNi2S4 surface by a hydrothermal method; the Z-type heterointerface constructed by the surface contact of the two materials under fusion shows a huge promotion effect on the catalytic ability. The performance (3754.3 μmol g−1 h−1) of the composite material (CW/CNS-12%) reached 42 and 6 times those of the two monomer materials, respectively, and the excellent catalytic ability of the composite is also reflected in its long-term stability. The experimental data proves that the modification of CuNi2S4 by building a heterostructure can improve the specific surface area of the material and the amount of carriers it generates. The charge transfer caused by the existence of the heterojunction hinders the recombination of carriers and holes; fluorescence and electrochemical characterization further confirms the charge transfer process in the Z-type heterojunction. This research provides new insights to promote catalytic performance by building heterostructures between monomer materials. [ABSTRACT FROM AUTHOR]

A photocatalytic material, NiCo2S4@Ni2P, with a unique hollow core–shell structure based on hollow spherical NiCo2S4, which has a structure that is greatly advantageous for heterogeneous photocatalytic reactions, was successfully prepared. The unique hollow core–shell structure formed a homogeneous surface heterojunction, which caused the composite photocatalytic material to exhibit better photocatalytic HER activity and stability than the initial NiCo2S4 in the dye-sensitized system. The photocatalytic HER rate of the optimal photocatalytic material, NiCo2S4@Ni2P 10%, reached 77.97 μmol h−1via the optimization of the photocatalytic H2 evolution performance. XRD and XPS were used to study the crystal structure and valence state of the photocatalytic material, respectively. Additionally, its morphology and structure were observed by SEM and TEM, respectively. The CB and VB potentials were derived by combining empirical formulas based on the UV-vis DRS data. Finally, the photocatalytic HER mechanism was investigated by photoelectrochemical and PL tests combined with the above data. [ABSTRACT FROM AUTHOR]

A Z-scheme heterojunction composite material Ni2P/RGO/MoO2 with high efficiency HER activity via a simple hydrothermal synthesis method which is one-step for photocatalytic H2 production was synthesized. The composite material which used reduced graphene oxide (RGO) as an electron transport medium and utilized a synergistic action of non-noble metal semiconductors Ni2P and MoO2 to construct Z-scheme heterojunction. Compared with the binary Ni2P/MoO2 composite photocatalyst, the photocatalytic hydrogen evolution activity of RGO assisted ternary composite Ni2P/RGO/MoO2 is significantly improved under visible light (λ > 420 nm) in the dye sensitization system in 5 h. The photocatalyst with optimal ratio reaches 355.34 μmol, which is about two times as much as the one without RGO. The transient photocurrent response, fluorescence test and hydroxyl radical capture experiment show that the type-II heterojunction originally composed of Ni2P and MoO2 is converted to Z-scheme in the presence of RGO. The transformation of the electron transfer mode effectively reduces the composite of photogenerated carriers. In addition, in situ hydrothermal synthesis allows Ni2P and MoO2 to be firmly modified on the RGO surface. This makes the composite photocatalyst exhibit great catalytic stability, and the HER activity of the photocatalyst hardly decrease in the four-cycle experiment. Through the one-step hydrothermal method, RGO assisted non-precious metal semiconductor composite provides a new idea for the synthesis of photocatalytic materials. The composite catalyst via the band gap regulation of MoO2 by Ni2P exhibits great hydrogen production activity in the dye-sensitized system. Subsequently, the GO solution was added during the synthesis to construct a Z-scheme heterojunction with graphene as an electron transporter. The ternary composite catalyst with a Z-scheme heterojunction shows approximately twice the hydrogen production rate of the binary catalyst. [ABSTRACT FROM AUTHOR]

Novel g-C 3 N 4 /MoS 2 /ZnS ternary heterojunction as high performance anode has been successfully designed and synthesized via a facile one-step hydrothermal process. The electrochemical reversibility of MoS 2 for Li+ storage is improved by g-C 3 N 4 and ZnS modification in this study. Electrochemical tests demonstrate that the g-C 3 N 4 /MoS 2 /ZnS electrode deliver a high reversible capacity of 1310 mAh g−1 at the current density of 0.1 A g−1 and a high rate capability (maintaining 84.5% at 800 mA g−1). Moreover, the electrode still can achieve a capacity of 805 mAh g−1 even at 1 A g−1. The enhanced electrochemical performance can be attributed to the synergetic effect between few-layer MoS 2 /ZnS heterojunctions and g-C 3 N 4 within the interface region, which provides excellent charge transfer field and availably restrains the corruption and aggregation during charging and discharging process. Unlabelled Image • The g-C 3 N 4 /MoS 2 /ZnS composites with artistic heteronanostructures were synthesized by one-step hydrothermal method. • The MoS 2 /ZnS heterojunctions is tightly anchored onto the surface of the g-C 3 N 4 nanosheets. • The ultrathin curved MoS 2 nanosheets with an average lattice spacing of 0.62 nm • The g-C 3 N 4 /MoS 2 /ZnS ternary nanocomposites exhibit high capacity and excellent cycling stability. [ABSTRACT FROM AUTHOR]

Semiconductor materials have been applied in many research directions such as photoelectrocatalysis, and shortening the electron transport pathway by coupling semiconductors is an effective path to promote the capability of photocatalytic hydrogen-producing. The crystalline SnS 2 and amorphous SnS 2 were combined with NiWO 4 respectively, in the respective optimal hydrogen-producing conditions, it was 298.6 μmol for SnS 2 /NiWO 4 (amorphous J-SnS 2 and NiWO 4) and 228.5 μmol for J-SnS 2 NiWO 4 (crystalline SnS 2 and NiWO 4). A series of characterization results showed that SnS 2 /NiWO 4 showed better photocatalytic hydrogen-producing performance than J-SnS 2 /NiWO 4 under the same test conditions. The catalysts SnS 2 and NiWO 4 were constructed into p-n type heterojunction SnS 2 /NiWO 4 by electrostatic self-recombination. SEM, XRD and electrochemical tests demonstrate that the high hydrogen-producing performance of SnS 2 /NiWO 4 is due to the establishment of p-n heterojunction, which enhances the electron transport efficiency. The experimental data were used to test the photocatalytic hydrogen-producing activity of SnS 2 /NiWO 4 with the control variable method, then it was proved that the photocatalytic hydrogen-producing volume of SnS 2 /NiWO 4 reached 298.6 μmol in 5 h, which was 3.51 times that of NiWO 4 at 5 h hydrogen-producing of 85 μmol. The morphology of nanoparticles NiWO 4 attached to a smooth surface sphere SnS 2 provides a larger specific surface area and more reactive sites for the photocatalytic eosin hydrogen-producing system, in addition the establishment of p-n type heterojunction structure effectively improves the utilization rate of the sacrificial TEOA and photosensitizer EY, thereby improving the hydrogen-producing performance of SnS 2 /NiWO 4 , which offers a feasible policy for photocatalytic efficient hydrogen-producing technology. • Nanoparticles of NiWO 4 was loaded onto different forms of SnS 2. • The hydrogen production of SnS 2 /NiWO 4 is 3.51 times that of NiWO 4. • Successful construction of SnS 2 /NiWO 4 p-n type heterojunction. • The reaction mechanism of the p-n type heterojunction was clarified. [ABSTRACT FROM AUTHOR]

NiCo-LDH with a layered structure was coupled to Mn 0.2 Cd 0.8 S through electrostatic self-assembly to construct tightly heterojunctioned photocatalysts. The bundles of stacked nanorods and the tightly packed sheets break the agglomeration of each other after electrostatic self-assembly, exposing more redox active sites. The introduction of NiCo-LDH further expands the light absorption of Mn 0.2 Cd 0.8 S towards the visible wavelength range, effectively improving the photoresponse performance. The charge density in NiCo-LDH increases after coupling and the transport direction of photogenerated carriers inside the photocatalyst follows the S-scheme heterojunction migration path. Photogenerated carriers are effectively separated, preserving the more redox-competent conduction band and valence band potentials. The reduction of charge transfer resistance and hydrogen evolution overpotential facilitated the hydrogen evolution reaction. Thus the optimised composite photocatalyst exhibits a significant improvement in hydrogen evolution performance (15.21 mmol·g−1h−1, approximately 28.17 times that of Mn 0.2 Cd 0.8 S) and maintained a good hydrogen evolution stability. [Display omitted] • Tight-contact NiCo-LDH/Mn 0.2 Cd 0.8 S photocatalyst was constructed through electrostatic self-assembly. • Charge transfer path following S-scheme heterojunction of NiCo-LDH/Mn 0.2 Cd 0.8 S is clarified. • Photocatalytic hydrogen evolution activity of NiCo-LDH/Mn 0.2 Cd 0.8 S reached 15.21 mmol·g−1·h−1. • 1D/2D interface enables fast migration of photogenerated carriers. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Bi 2 O 2 CO 3 /SrTiO 3 heterostructure is synthesized by a simple hydrothermal method. • The Bi 2 O 2 CO 3 /SrTiO 3 heterostructure has ideal channels for charge transport due to crystal facet matching. • Direct Z-schemes for Bi 2 O 2 CO 3 /SrTiO 3 can facilitate efficient migration and separation of photogenerated carriers. • A higher adsorption energy of CHOO– and CO for Bi 2 O 2 CO 3 /SrTiO 3 make an excellent performance. Herein, a two-dimensional/two-dimensional (2D/2D) Bi 2 O 2 CO 3 /SrTiO 3 (BOC/STO) direct Z-schemes heterojunction photocatalysts with perfect lattice matching are successfully prepared for efficient photocatalytic CO 2 reduction. Results show that as-prepared BOC/STO composites follow the orientation relationship of (0 2 0) BOC // (2 0 0) STO and both two planes have a lattice spacing of 0.26 nm, resulting in the formation of perfect lattice matching between BOC and STO, which implying BOC/STO heterostructure has an ideal channel for charge transport. In addition, the DFT calculation confirms the direct Z-schemes heterojunction is formed at the BOC/STO interface, which can facilitate efficient migration and separation of photogenerated carriers. Combining the advantage of direct Z-schemes heterojunction and good lattice matching, the optimized BOC/STO catalyst performs the photocatalytic reduction of CO 2 to CO and CH 4 which are ∼ 2.61 times and ∼ 20.47 times for STO, respectively. The selectivity of 20 %-BOC/STO for CH 4 increases to 79 %. The calculations confirm the higher adsorption energy of CHOO– and CO and the lower reaction energy of CHO– on BOC/STO than pure BOC or STO, resulting in the higher selectivity performance of BOC/STO for CO 2 photocatalytic reduction. [ABSTRACT FROM AUTHOR]

Constructing S-scheme heterojunction derived from metal-organic frameworks (MOFs) with high photoredox ability and boosted charge separation efficiency is promising in photocatalytic wastewater treatment. Herein, the MOF-BiOCl composite composed of BiOCl nanosheets and rod-like Bismuth-MOF (CAU-17) as the bismuth source precursor was prepared in situ via a halogenation process. Rational coupling the MOF-BiOCl with MoS 2 nanosheets, an S-scheme heterojunction with enhanced photocatalytic tetracycline (TC) degradation efficiency was constructed. The optimized MOF-BiOCl/MoS 2 -3 composite exhibited the highest TC degradation rate (90% in 20 min). The improvement of photocatalytic degradation is mainly due to i) in situ synthesis of BiOCl nanosheets derived from Bismuth-MOFs avoided the aggregation of individual BiOCl nanosheets and preserved the ultrahigh porosity and specific surface area of the MOFs which generated more adsorption sites; ii) driven by the formed internal electric field, the charges followed an S-scheme transfer rout which retained the highest redox potential; iii) the 2D/2D BiOCl/MoS 2 nanosheets geometry provided more intimate interfacial contacts which accelerate the charge separation and migration. This work offers an ideal strategy for constructing the effective heterostructure photocatalyst in the photocatalytic wastewater treatment. • 2D/2D Bi-MOF-derived BiOCl/MoS 2 S-scheme heterojunction S-scheme heterojunction was constructed. In situ synthesis of BiOCl nanosheets derived from Bismuth-MOFs avoided the aggregation of individual BiOCl nanosheets and preserved the ultrahigh porosity and specific surface area of the MOFs, which generated more adsorption sites and favoured the toxic molecular adsorption. • An S-scheme reaction mechanism facilitated charge separation and afforded high photoredox ability. Driven by the formed internal electric field, the charges followed an S-scheme transfer route which retained the highest redox potential and boosted separation ability. • High photocatalytic degradation activity, as well as stability, was achieved. The 2D/2D morphological characteristic and intermate interface of the heterostructure provided more intimate interfacial contacts, which accelerated the charge separation and migration. [ABSTRACT FROM AUTHOR]

The nanostructured ZnO film was prepared on a texturized Si wafer by a simple sol-gel method to fabricate n-ZnO/ p-Si heterojunction photoelectric device. The novel sol-gel method is cheap and convenient. The structural, optical and electrical properties of the nanostructured ZnO film were studied by XRD, SEM, XPS, PL, UV-Vis spectrophotometer and Hall effect measurement. The current-voltage (I-V) curve of nanostructured ZnO/ p-Si heterojunction device shows good rectifying behavior. Good photoelectric behavior is obtained. [ABSTRACT FROM AUTHOR]

In this work, magnetic oxygen vacancy-BiOBr/CoFe 2 O 4 (OV-BiOBr/CoFe 2 O 4) composite with Z-scheme heterojunction was prepared by simple solvothermal method. The physicochemical properties of the prepared samples were characterized. The degradation rate of norfloxacin (NOR) by OV-BiOBr/CoFe 2 O 4 under visible light irradiation can reach 94.61%. In addition, OV-BiOBr/CoFe 2 O 4 composite also exhibits excellent photocatalytic performance for other antibiotics, it can be recovered by external magnetic field and still shows good photocatalytic activity after four consecutive times uses. Characterization and experimental results show that the improved photocatalytic performance of OV-BiOBr/CoFe 2 O 4 can be attributed to the improvement of visible light response range, the increase of active sites and the effective separation of electron hole pairs. The results of free radical capture experiment and electron paramagnetic resonance spectra show that •O 2 − and h+ are the main active substance in photocatalytic degradation of NOR system. Then, combined with the band structure, a Z-scheme heterojunction electron transfer mechanism is proposed. This work enhances the photocatalytic performance of BiOBr and provides a new idea for antibiotic wastewater treatment. A novel OV-BiOBr/CoFe 2 O 4 heterojunction photocatalyst has been synthesized, which has high visible light catalytic activity for Norfloxacin (NOR). The existence of oxygen vacancy broadens the spectral response range of BiOBr, and the photogenerated carriers can be separated effectively after further compounding with CoFe 2 O 4 , which makes the composite have higher degradation rate than pure BiOBr and CoFe 2 O 4. Based on the experimental and characterization results, a possible electron transfer mechanism is proposed. [Display omitted] [ABSTRACT FROM AUTHOR]

• 2D stannous sulfide nanosheets coated molybdenum disulfide nanotube constructed hierarchical nanostructure is obtained by using conventional template method. • The specific discharge capacity reaches up to 819 mA g−1, and the initial coulombic efficiency is 81.8%. • The discharge capacity is maintained at 430.7 mAh g−1 with decay of only 7.2% after 300 cycles at 1000 mA g−1. Coupling the composite electrodes formed by two different semiconductors is an effective way to enhance the charge transfer rate and interfacial reaction kinetics of electrodes. In this work, two-dimensional stannous sulfide nanosheets (SnS) coated molybdenum disulfide (MoS 2) nanotube constructed hierarchical nanostructure is obtained by using conventional template method, and the battery properties are studied in detail. The specific discharge capacity of the composite material reaches up to 819 mAh g−1, and the initial coulombic efficiency (CE) is 81.8% at first cycle. The discharge capacity is maintained at 430.7 mAh g−1 with decay of only 7.2% after 300 cycles at 1000 mA g−1. These impressive discharge properties may be related to the designed layered structure that accelerates the separation and transfer rate of ions and electrons at the electrode interface. The unique hierarchical structure can also provide abundant reaction binding sites, buffer the electrode volume change, and thus enhance the sodium storage performance. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports a large enhancement of planar Hall sensitivity in Ta/NiFe/Ta films by intercalating NiO layers to Ta/NiFe and NiFe/Ta interfaces. The great improvement of the sensitivity derives from the increase of resistivity change (Δρ) and the decrease of saturation field (H s ). The enhancement of Δρ could be attributed to the strengthened spin dependent elastic scattering to the interfacial conductive electrons due to flat oxide/metal interfaces. Meanwhile, the existence of oxide (NiO) prevents the atomic interdiffusion of Ta and NiFe at the interfaces, which leads to the easier magnetization rotation of NiFe layer, resulting in lower saturation field. [Copyright &y& Elsevier]