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Selective growth of cocatalyst on the surface of photocatalyst has been attracted considerable attention due to their efficient charges transfer property. In this study, the robust NiS modified graphitic carbon nitride (g-C3N4) hybrids were successfully synthesized by a facile surface photochemical deposition process. The structure and composition characterization results revealed that the NiS is highly dispersed loading on the surface of g-C3N4 nanosheets, and the NiS/g-C3N4 hybrids possess large surface areas and excellent optical properties. Under the visible light illumination, the NiS/g-C3N4 hybrids with 1.0% weight content of NiS cocatalyst exhibits the highest hydrogen evolution rate of 1346.1 μmol h−1 g−1 with an apparent quantum efficiency (AQE) of 7.67%. On the basis of photoluminescence (PL) spectra and photoelectrochemical methodology, the photocatalytic hydrogen evolution mechanism was proposed. The results demonstrated that the excellent activity arises from the strong electronic coupling, highly efficient charges separation and migration. This work demonstrates a facile photochemical deposition method to consciously construct the robust two-dimensional (2D) hybrids, so as to realize accurate deposition of cocatalyst and efficient migration of photo-generated carriers. [ABSTRACT FROM AUTHOR]

[Display omitted] The exploration of highly efficient sunlight-assisted photocatalyst for photodegradation of organic contaminants or energy conversion is strongly encouraged. In this work, we designed a novel three-dimensional spindle-like Sv-ZIS@NMFe heterojunction made of amino functionalized NH 2 -MIL-88B(Fe) (NMFe) and ZnIn 2 S 4 nanosheets with abundant sulfur vacancies (Sv-ZIS). The structural properties of NMFe materials, such as a clearly defined system of pores and cavities, were retained by the Sv-ZIS@NMFe composites. Additionally, the incorporation of sulfur vacancies, –NH 2 functional groups, and well-matched energy level positions led to various synergistic effects that considerably enhanced internal electron transformation and migration, as well as improved adsorption performance. Consequently, under visible light irradiation, the optimized sample exhibited superior hydrogen production activity and tetracycline hydrochloride photodegradation performance. At last, density functional theory calculations was used to further elucidated the possible photoreactivity mechanism. This study demonstrates that the Sv-ZIS@NMFe heterojunction materials formed by ZnIn 2 S 4 with suitable sulfur vacancies and amino functionalized Fe-MOFs have promising applications in photocatalysis. [ABSTRACT FROM AUTHOR]

Se decorated CdS nanowires with few-layer MoSe 2 nanosheets are fabricated for efficient H 2 production. The piezoelectric field of MoSe 2 nanosheets promotes the separation of free charges. Compared with the photocatalysis, the piezo-photocatalysis yields a superior H 2 evolution rate of 59.1 mmol/h g−1 (124.9% that of photocatalysis). [Display omitted] The build-in electric field by the construction of heterojunction is one of the most promising strategies to suppress the recombination of photogenerated carriers. Here, we reported a piezo-photocatalytic system composed of Se-decorated CdS nanowires and few-layered edge-on MoSe 2 nanosheets for efficient H 2 generation by two-pot hydrothermal synthesis. The few-layered MoSe 2 exposed abundant edge sites for hydrogen evolution reaction (HER). The activity of 20-MoSe 2 /CdS 0.95 Se 0.05 (20-MS/CSS, with 20 mol% of MoSe 2 loading) nanocomposite casted a remarkable photocatalytic HER performance, with a rate of 47.3 mmol h−1 g−1. Moreover, MoSe 2 nanosheets deformed to generate the piezoelectric polarization field under magnetic stirring, which rendered efficient separation of photogenerated carriers, resulting in a piezo-photocatalytic synergistic effect. As a result, the HER of 20-MS/CSS at 900 rpm for piezo-photocatalysis was 59.1 mmol h−1 g−1, which was 1.25 times that of 20-MS/CSS for photocatalysis. Meanwhile, the photoelectrochemical measurements further visualized the piezo-photoelectric synergy. This study exposes a new way for utilizing mechanical energy to improve photocatalytic performance, and achieving high piezo-photocatalysis. [ABSTRACT FROM AUTHOR]

Ternary nanocomposites comprised of one-dimensional (1D) WO 3 &WS 2 nanorods (NRs) and CdS nanoparticles (NPs) fabricated through a two-step process were characterized using a combination of X-ray, microscopy, and spectroscopy techniques. The amount of CdS strongly influences the properties of the nanocomposites, with 40 wt.% of CdS loading showing optimal optical properties and photoelectrochemical (PEC) as well as photocatalytic activities for hydrogen evolution reaction (HER). Compared with WO 3 &WS 2 NRs, the optimized nanocomposite shows 11.4 times enhancement in photocurrent and 6 times increase for HER with lactic acid as a sacrificial agent. The enhanced PEC and HER activities can be attributed to CdS absorption of visible light as well as the intimate contact between WO 3 &WS 2 and CdS that efficiently enhances charge carrier separation. This work demonstrated a promising strategy in the design and fabrication of high-performance photocatalysts for photocatalytic HER applications. [ABSTRACT FROM AUTHOR]

A ZnIn 2 S 4 @NiCo 2 S 4 hollow tubular nanocomposite serves as a green, sustainable and high performance photocatalyst toward the photocatalytic hydrogen evolution. [Display omitted] • A novel noble metal-free ZnIn 2 S 4 @NiCo 2 S 4 hollow tubular composites were synthesized based on the combination of semiconductor and metal-like. • The H 2 production ability of the optimal ZnIn 2 S 4 @NiCo 2 S 4 photocatalyst was about 6.1 times higher than prinstine ZnIn 2 S 4. • The optimal ZnIn 2 S 4 @NiCo 2 S 4 photocatalyst exhibits excellent apparent quantum efficiency and long-term stability. • The photoelectric transfer mechanism were carefully investigated. • A feasible Schottky junction reaction mechanism was proposed. To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of ZnIn 2 S 4 semiconductor photocatalyst, herein, in situ growth of 2D ZnIn 2 S 4 (ZIS) on the surface of NiCo 2 S 4 (NCS) hollow tubes was designed and prepared through a multistep solvothermal means. The experimental results indicate that the ZIS@NCS composites possess large specific surface area and abundant photocatalytic active center due to the intimate interface contact between ZIS nanosheets and NCS hollow backbones, which are favorable for visible light absorption and the interfacial carrier transfer in photocatalytic reaction process. Density functional theory further proved the above insights. The dynamics of photo-induced electrons were extensively characterized. As a result, the optimal sample of ZIS@NCS-7 exhibited the highest hydrogen evolution rate of 1950 μmol h−1 g−1, which was 6.1 times that of pristine ZIS and much higher than the other photocatalysts under otherwise identical conditions. The apparent quantum efficiency of ZIS@NCS-7 composites reached 9.3% at 420 nm. This work provides a novel standpoint for the design and construction of more efficient photocatalyst with robust light absorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel MOF-derived three-dimensional CoSe 2 /Cd 0.8 Zn 0.2 S Schottky junction is successfully fabricated. • CoSe 2 with larger work function and a polyhedral hollow structure provides abundant active sites. • The highest HER rate of CoSe 2 /Cd 0.8 Zn 0.2 S hybrids is 80 times higher than that of Cd 0.8 Zn 0.2 S. The well-designed interface plays a key role in enhancing the charge transfer kinetics. In this work, a three-dimensional CoSe 2 /Cd 0.8 Zn 0.2 S Schottky junction was successfully prepared using zeolitic imidazolate framework-67 (ZIF-67) as precursor material by in-situ chemistry synthetic strategies to improve the charge transfer kinetics. The photocatalytic H 2 generation rate of 3.2%-CoSe 2 /Cd 0.8 Zn 0.2 S is 80 times higher than pristine Cd 0.8 Zn 0.2 S. The systematic characterization (XPS, TRPL, EPR, etc.) and DFT results show the improvement of photocatalytic performance derives from the formation of Schottky junction between CoSe 2 and Cd 0.8 Zn 0.2 S. The well-designed and tight interface can facilitate electrons transfer from Cd 0.8 Zn 0.2 S to CoSe 2 , and Schottky barrier can suppress the electrons flow back to Cd 0.8 Zn 0.2 S, resulting in the high separation of charge carriers. On the other hand, the noble metal-free CoSe 2 with larger specific surface area function as the electron acceptors and active sites for reducing H+ to H 2 efficiently, thus in favor of obtaining the enhanced H 2 generation performance. Combining the three-dimensional structure with Schottky junction, this work provides an effective strategy to prepare photocatalysts. [ABSTRACT FROM AUTHOR]

• NiCo 2 S 4 /CdS showed excellent HER with lactic acid under visible light irradiation. • Ultrafast dynamics studies showed that NiCo 2 S 4 /CdS had more efficient charge separation. • The mechanism enhanced performance of the NiCo 2 S 4 /CdS nanocomposites were revealed. One-dimensional NiCo 2 S 4 /CdS nanocomposites are constructed using a two-step hydrothermal method and used for photocatalytic hydrogen generation with visible light. The nanocomposites are characterized using a combination of techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), positron annihilation lifetime measurement, spectroscopy techniques, and femtosecond transient absorption (TA) spectroscopy. In comparison to bare CdS NWs, the NiCo 2 S 4 /CdS nanocomposites exhibit enhanced visible light hydrogen production, with an optimal rate reaching 20.0 mmol·h−1·g−1. The experimental results, in conjunction with theoretical electronic structure calculations, reveal that the enhanced hydrogen evolution reaction activities can be attributed to the formation of Schottky junction between NiCo 2 S 4 NPs and CdS NWs that facilitates photogenerated electron transfer from CdS to NiCo 2 S 4. Meanwhile, the NiCo 2 S 4 , as a metallic cocatalyst, increases the electron density and active sites desired for H 2 evolution. [ABSTRACT FROM AUTHOR]