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An efficient photocatalytic system composed of Ti3C2 quantum dots incorporated TiO2 nanosheets and CuWO4 nanoparticles for H2 production.

A highly SERS active substrate of AgNPs on the Al/ZnO has been developed. It can be used for the selective detection of crystal violet in actual water samples.

A mixed phase LaVO4 with high dispersion was in situ induced and implanted in graphene oxide-graphite carbon nitride composite. The obtained nanocomposite (GO–C3N4–LaVO4) showed high and stable photocatalytic activity for hydrogen evolution, which significantly benefited from the improved charge separation and light absorption in the special composite photocatalyst as evidenced by UV–vis spectra, fluorescence spectrum, photocurrent response and electrochemical impedance. The fabrication strategy of mixed phase LaVO4 in the GO-C3N4 provides a new idea for constructing cheap and active organic-inorganic semiconductor photocatalysts for hydrogen generation.

It has been regarded as a promising strategy utilizing Cu co-catalyst to prepare efficient TiO2-based photocatalysts. Traditionally, Cu co-catalyst is directly loaded on the surface of TiO2. Herein, we designed and prepared an innovative photocatalytic system, Cu nanoclusters incorporated mesoporous TiO2 nanoparticles which possess plum pudding-like structure, to enhance the interaction between Cu co-catalyst and TiO2, and the stability of Cu co-catalyst. The results indicate that the as-prepared nanoparticles are an efficient noble metal-free photocatalyst for H2 production. The highest H2 evolution rate is up to 5.9 mmol g−1 h−1. Here, the Cu nanoclusters play three roles as follows: traps of the photogenerated electrons, active sites, and harvesters of visible light. Moreover, the stability of Cu co-catalyst can be obviously enhanced via embedding Cu co-catalyst into TiO2 matrix. This work provides a new route to an efficient and stable photocatalytic system containing TiO2 and Cu for photocatalytic H2 production.

It is necessary for the commercialization of sunlight-driven H2 evolution to develop an efficient photocatalytic system whose energy utilization is independent of incident light intensity. Unfortunately, limited attention has been paid to the effect of light intensity on energy utilization. For all the above reasons, a photocatalytic system made up of eosin Y, ZnWO4 nanoplates and CuO nanoparticles was fabricated. Meanwhile, its photocatalytic activity for H2 evolution was evaluated under illumination with various light intensities. In light of the experimental results, we can conclude that the aforementioned system possesses dramatic photocatalytic performance for H2 evolution. Under strong illumination (100 mW cm−2), the highest H2 evolution rate is as high as 4.9 mmol g−1 h−1. Even if under weak illumination (10 mW cm−2), the H2 evolution rate is still 0.53 mmol g−1 h−1. More interesting, the energy utilization of this system is independent of light intensity. These results might provide some new ideas for the design and preparation of high-efficiency photocatalysts with light intensity-independent energy utilization.

In order to obtain a highly efficient photocatalyst for hydrogen evolution, an excellent photo active molecule, tetra (p-carboxylphenyl) porphyrin (TCPP) was introduced and orientedly attached on an antennae-like Cu2O/NiO heterostructure. Subsequently, heterogeneous Cu2O/NiO/TCPP nanocomposites were achieved. Assembly mechanism of the nanocomposites was investigated in detail. The results showed that, by coordination interaction and hydrogen bond, TCPP molecules can be strongly assembled onto the NiO-riveted Cu2O. Because of strong interaction among Cu2O, NiO and TCPP, and the enhanced light absorption, quick transfer of more photo-generated electrons can be achieved. Furthermore, the nanocomposite displayed a higher photocatalytic activity compared with other contrast materials (Cu2O/NiO/NiTCPP, Cu2O/NiO, Cu2O et al.). It was attributed to the improved separation of charges as well as light absorption, which was originated from the well-matched band structure and special heterogeneous interface. This study will open up new perspectives for the fabrication and application of heterojunction photocatalysts.

In this work, worm-like SnS2 nanoparticles were prepared by a hydrothermal process. And then their photocatalytic activity was explored for the restoration of effluent containing Cr (VI). The results indicate that the product obtained is hexagonal SnS2 nanoparticles and adopts a worm-like morphology with length of approximate 6 nm and diameter of 3 nm. Moreover, the as-prepared SnS2 nanoparticles possess high photocatalytic activity for the visible light-driven reduction of Cr (VI). When the concentration of Cr (VI) is 4 × 10−4 mol/L, 99% Cr (VI) can be reduced over the as-prepared SnS2 nanoparticles within 30 min under visible irradiation.

This work proposes a novel carbon nitride-based hybrid (g-C3N4/Cu/THPP) with small-sized Cu as the bridging linker for improving the photocatalytic activity of graphitic carbon nitride (g-C3N4)/tetrakis-(4-hydroxyphenyl)porphyrin (THPP). It was found that the special Cu linker had a great influence on the microstructure and photocatalytic H2 production of the C3N4/THPP nanohybrid. The photocatalytic activity was enhanced by about 17.3 times compared to that of pristine g-C3N4 and about 11.6 times higher than that of g-C3N4/THPP. Especially, it was enhanced by about 3.1 times than that of g-C3N4/CuTHPP (a comparative composite without the Cu bridge). Furthermore, the photocatalysis mechanism was investigated in detail. The results demonstrated that interfacial modification with the special Cu linker was key in improving the absorption, electron/hole separation and photocatalytic performance of the nanohybrid. This work provides a facile strategy for preparing highly efficient photocatalysts through interfacial modifications with special metals.

In recent years, it is urgent to develop bi-functional materials for highly sensitive SERS detection and photocatalytic degradation of contaminants in water of fish pond. Herein, using 5-mercapto-1-methyltetrazole as the ligand, the tree-trunk like zeolitic imidazolate framework (ZIF-8) is induced and in-situ grown on the surface of aluminum/flower carbon nitride (Al/f-C

The sensitive detection of malachite green (MG) in aquaculture wastewater is necessary for its residual poses a great threat to the living systems. Herein, the flower-like C3N4 (f-C3N4) nanostructure induced by Al sheet in the hydrothermal process is constructed. Subsequently, Ag nanowires (AgNWs) supported on Al/f-C3N4 and the strong interaction between AgNWs and Al/f-C3N4 are confirmed by XPS, Raman spectroscopy, UV–vis diffuse reflectance and fluorescence spectroscopy. Importantly, the portable Al/f-C3N4/AgNWs substrate shows the outstanding SERS response for MG, which is attributed to enhanced electromagnetic effect of AgNWs on large amount of corrugated and creviced regions in the flower-like Al/f-C3N4 and the charge transfer among the components. Also, the prepared Al/f-C3N4 nanostructure provides large specific surface area and abundant “N” active sites for AgNWs, and the high enrichment ability of Al/f-C3N4 towards MG molecules by the strong π-π stacking interaction. The detection limit of Al/f-C3N4/AgNWs for MG is as low as 8.38 × 10−12 mol L−1. The substrate can be reproduced and reused for at least 7 cycles, and the activity can still be kept after laid up for 49 days. Importantly, it unfolds a good sensitivity and selectivity for MG in actual water sample. Results indicate that the Al/f-C3N4/AgNWs substrate has a promising potential in practical application for trace detection of MG.

Mono-dispersed nanometals could act as excellent cocatalysts. However, nanometals were apt to be oxidized and aggregated, and their activity was decreased. Herein, well-dispersed and small-sized Cu nanoparticles controlled by the mesoporous of TiO2 microspheres (TiO2 MS) were prepared. It was found that the Cu implanted into the hybrid (Cu–TiO2 MS) was mainly in the form of Cu0 with high dispersion and stability. Furthermore, the electron transfer can be significantly accelerated, the absorption of TiO2 can be improved, and the over-potential of hydrogen evolution was reduced. Thereby, it showed higher photocatalytic activity and good stability compared with those of the Cu-P25.

Semiconductor nanophotocatalysts with high performance for hydrogen (H2) generation require well-designed and optimized interfaces. This work aimed at the rational design and facile assembly of a h...

A photocatalytic integrated system containing Pt nanoclusters, CoWO4 nanoclusters and C3N4 nanosheets was achieved through a hydrothermal process followed by photodeposition. Meanwhile, the photocatalytic activity of the as-prepared system was explored for light driven H2 evolution. Finally, the photocatalytic mechanism was explored roughly. The results show that there exists strong synergistic effect between Pt and CoWO4. The photocatalytic activity of C3N4 can be significantly enhanced utilizing the aforementioned synergistic effect. When the as-prepared photocatalytic system is used, the fastest evolution rate of H2 can be up to 14.2 μmol h−1, which is 2.1 times as high as that over the Pt modified C3N4 nanosheets (6.7 μmol h−1). And the quantum yield of the as-prepared photocatalytic system at 400 nm (0.018%) is also much higher than that of the Pt modified C3N4 nanosheets (0.004%). Here, this remarkable photocatalytic activity ought to be attributed to superior separation of the electro-hole pair caused by efficient charge transfer in the photocatalytic system which follows a Z-scheme-like mechanism. Therein, Pt nanoclusters may serve as an electron transfer pathway between CoWO4 and C3N4 as well as active sites while CoWO4 nanoclusters may play a water oxidation cocatalyst.

Sn3O4 flower-like hierarchical nanostructures were prepared by a hydrothermal process without the help of templates or surfactants. Meanwhile, photocatalytic H2 evolution from water over the as-prepared Sn3O4 hierarchical nanostructures was explored using methyl alcohol as a sacrificial reagent. The results indicate that the Sn3O4 hierarchical nanostructure adopts spherical flower-like morphology assembled from nanosheets. Moreover, the Sn3O4 flower-like hierarchical nanostructure is an efficient photocatalyst for visible-light-driven H2 evolution from water. Under optimal conditions, the H2 evolution rate over the Sn3O4 hierarchical nanostructure is up to 184 μmol h−1 g−1.

Here, by a simple one-step in situ chemical reduction method, the AgxCuy alloy was tailored on the surface of mesoporous TiO2 (M-TiO2), therefore, a series of bi-functional mesoporous TiO2 nanohybrids (M-TiO2/AgxCuy) for both surface enhanced Raman scattering (SERS) detection and photocatalytic degradation of ampicillin (AMP) were achieved. The composition and structure of the nanohybrids were well characterized using XRD, TEM, XPS and HRTEM-EDS measurements. Results indicated that AgxCuy alloy was mainly attached around the pores of M-TiO2 which may generate more active sites than nonporous P25−Ag−Cu. Thus, the M-TiO2/AgxCuy nanohybrids could be used as efficient SERS substrates to sensitively monitor the AMP in water with lower detection limit (˜ 1 ppt) than P25−Ag−Cu. Besides, the M-TiO2/Ag3Cu1 nanohybrid also showed higher photocatalytic activities for the degradation of AMP under UV irradiation over the M-TiO2/Ag, the M-TiO2/Cu and the P25−Ag−Cu. This work provided a simple and effective approach to synthesize bi-functional nanohybrids for detection and degradation of organic contaminants in wastewater.

Development of photocatalysts with high activity and durability for hydrogen generation is extremely desired but still remains a great challenge currently. With Cu nanoparticles (Cu NPs) as a linker between TiO2 microsphere (TiO2 MS) and 5, 10, 15, 20-meso-tetra(4-carboxyphenyl)porphyrin (TCPP), a novel nano-micro hybrid (TiO2 MS-Cu-TCPP) was prepared via a facile method. By bridging TiO2 MS and TCPP with Cu NPs, the absorption and the electron transfer of TiO2 MS were greatly improved. When the TiO2 MS-Cu-TCPP was employed as the photocatalyst for hydrogen evolution, it exhibited higher activity and stability than those of the TiO2 MS, the TiO2 MS-Cu and the TiO2 MS-TCPP, TiO2 MS-Cu-CuTCPP and TiO2 MS-TCPP-Cu. The photocatalytic activity was enhanced for about 6 times with respect to that of the pristine TiO2 MS. The excellent performance for the nano-micro hybrid can be attributed to wide light absorption, more reactive sites, and facilitated interfacial electron transfer owing to the strong interaction between TiO2 and TCPP with Cu NPs as the linker and cocatalyst. Subsequently, a high and stable photocatalytic activity over the TiO2 MS-Cu-TCPP nano-micro hybrid was achieved, demonstrating the importance of interfacial modification to a semiconductor photocatalyst. This result gives us a new perspective of constructing special structures for efficient light utilization and electron transfer.

Development of highly active photocatalysts is one of the key topics for H2 production. Modifying the microstructure and exploring the electron transfer mechanism of the materials are very vital to achieve high-quality catalysts. Herein, by means of the bridging of rare-earth ions (Ln), a novel nanohybrid (GO–Ln–DPDPP) constructed of graphene oxide (GO) pillared with 5,15-diphenyl-10,20-di(4-pyridyl)porphyrin (DPDPP) was prepared by electrostatic interaction combined with coordination interaction. It was shown that the microstructure and morphology of the nanohybrid were greatly affected by the Ln introduced. Meanwhile, photoproduced electron transfer in the hybrid can be effectively promoted by the Ln implanted in the GO. Photocatalytic H2 production and the electron transfer mechanism were further explored. It was shown that, on the basis of the bridging of the Ln, lower interfacial resistance and higher separation of electron and hole caused by the strong interaction between DPDPP and GO were responsib...

In the present work, Ti mesh loaded with Ag “nanobosk” was prepared through electro-deposition and characterized with X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Then, the surface enhanced Raman scattering of norfloxacin on the Ti mesh loaded with Ag “nanobosk” was directly explored in norfloxacin aqueous solution. In addition, for practical purposes, the surface enhanced Raman scattering of norfloxacin was studied as a function of content of Ag, pH of solution, ions in water, and salinity, respectively. At last, the surface enhanced mechanisms were discussed preliminarily. The results indicate that the Ti mesh loaded with Ag “nanobosk” is an ultrasensitive surface enhanced Raman scattering substrate for trace norfloxacin in water. When the concentration of norfloxacin is 1 × 10−5 mol L−1, the enhancement factor is approximately 5.1 × 103 at 1389 cm−1. And the detection limit is up to 1 × 10-10 mol L−1 for norfloxacin under optimal conditions. Our work provides a new strategy for designing a sensing platform which is sensitive to trace norfloxacin in water and can be applied in the routine detection.

Development of highly-active photocatalyst is of critical challenge for hydrogen production from water reduction, and optimizing the microstructure and the composition of the relative materials is very necessary to obtain the high-quality catalysts. Here, a novel self-adjusting structure of pompoms-like cadmium molybdate nano-micro hybrid stimulated by copper ions (Cu-CdMoO4) was achieved. It was found that the morphology and property of the CdMoO4 can be modulated greatly by the Cu. The optimal H2 generation amount for the hybrid was about 77.4 times higher than that of pure CdMoO4 under same conditions. The significantly improved activity is associated with wider light response, more active sites, and effective charge separation.

In the present work, an Ni5P4/Ni porous composite with a Ni foam as the skeleton was prepared through phosphorization calcination at 500 °C. Meanwhile, the catalytic activity of the as-prepared Ni5P4/Ni porous composite was explored for the treatment of a large-volume effluent with a high concentration of 4-nitrophenol at room temperature. At last, the catalytic mechanism was discussed preliminarily. The results indicated that the Ni5P4/Ni porous composite possessed remarkable catalytic activity for the borohydride-assisted reduction of 4-nitrophenol. When the concentration of 4-nitrophenol was 1.0 × 10−3 mol L−1, the catalytic reduction efficiency of 4-nitrophenol was up to 99% within 13 min over the aforementioned sample. More interestingly, it was suitable for the treatment of a large-volume effluent with a high concentration of 4-nitrophenol. Almost 99% of 4-nitrophenol (1.0 × 10−2 mol L−1, 100 mL) could be removed within 30 min. Even when 4-nitrophenol was near saturation in water (5.0 × 10−2 mol L−1), 4-nitrophenol could still be removed absolutely from water after a 165 min reaction in the presence of the Ni5P4/Ni porous composite. In the catalytic process, Ni5P4 could serve as the active sites and accelerate the formation of hydrogen atoms from BH4−. Meanwhile, the Ni skeleton could make the electron transfer faster in the catalytic system. Besides, the macroporous structure of the sample also played an important role in the catalysis process.

In the present work, Ti3+ self-doped TiO2 nanoparticles were prepared in a simple one-pot solvothermal process. Meanwhile, the photocatalytic activity of the as-prepared TiO2 nanoparticles was explored under visible light irradiation for the treatment of effluent containing Cr(VI). Finally, the photocatalytic mechanism was discussed. The results show that the Ti3+ self-doped TiO2 nanoparticles obtained are an efficient visible photocatalyst for the reduction of Cr(VI). When the concentration of Cr(VI) is 10 mg L−1, about 95% of Cr(VI) can be removed within 1 min. More interestingly, the aforementioned TiO2 nanoparticles are a promising candidate with remarkable visible photocatalytic activity for the fast treatment of highly concentrated Cr(VI) effluent. When the concentration of Cr(VI) is 34 mg L−1, the reduction ratio of Cr(VI) is approximately 95% after 12 min of visible irradiation. Even if the concentration of Cr(VI) is very high (104 mg L−1), the reduction ratio of Cr(VI) is still up to 94% after 5 h of irradiation. Our work provides a new strategy for designing an efficient visible photocatalyst which is suitable for the rapid removal of highly concentrated Cr(VI) for environmental therapy.

Strontium vanadate nanoparticles embedded graphitic carbon nitride (g-C3N4/Sr2V2O7) was facilely prepared in situ via a hydrothermal method. It was shown that the Sr2V2O7 nanoparticles implanted into g-carbon nitride had a small size and high distribution. Importantly, compared with some other photocatalysts, the as-prepared g-C3N4/Sr2V2O7 nanohybrid showed excellent photocatalytic activity for reduction of Cr(VI), and as high as 99% efficiency for Cr(VI) reduction (100 mg L−1) was reached within 8 min. Moreover, its activity was hardly changed after five cycles, demonstrating that the developed g-C3N4/Sr2V2O7 nanohybrid was highly stable and promising an efficacious disposal of Cr(VI) in water. It was confirmed that the improved charge separation owing to more nitrogen vacancies in the hybrid was the main reason for the improved performance of the g-C3N4-Sr2V2O7 nanohybrid.

The sensitive detection and rapid removal of 4-aminothiophenol (4-ATP, a poisonous pesticide) demand special design to potential substrates. Herein, a metal-organic framework (ZIF-8) and Ag nanoparticles were fabricated one by one on the TiO2 coated Al sheet, and thus the Al–TiO2-ZIF-8-Ag sheet with sandwich structure was successfully synthesized. The cost-effective Al–TiO2-ZIF-8-Ag sheet (3.7 wt% Ag) possessed a low detection concentration of 1 × 10−9 M towards 4-ATP, and surface-enhanced Raman scattering (SERS) analytical enhanced factor (AEF) of the Al–TiO2-ZIF-8-Ag was 2.6 × 106, which was higher than other similar substrates. Furthermore, 4-ATP can be selectively and repeatedly detected on the Al–TiO2-ZIF-8-Ag even through it was in real samples. It indicated that the Al–TiO2-ZIF-8-Ag was a very active and stable SERS materials for the monitoring of 4-ATP. Importantly, the substrate exhibited faster and more efficient photocatalytic activity for 4-ATP degradation. The SERS and photocatalytic mechanisms of 4-ATP on the Al–TiO2-ZIF-8-Ag substrate were proposed. The cost-effective Al–TiO2-ZIF-8-Ag sheet with double function is plug-and-play, and could be used in the detection and treatment of pollutants in wastewater.

In this work, the graphene quantum dots (GQDsx, x = 1, 2 and 3) with various surface states were synthesized. Subsequently, GQDsx were facially assembled with glycine derivative (G6) and gold nanoparticles (AuNPs), and novel AuNPs/G6/GQDsx composites were achieved. Furthermore, the fluorescence and SERS results showed the strong dependence on the surface state of GQDs excluding the quantum size effects, which demonstrated the close relationship between the energy transfer efficiency of photoexcited GQDsx and AuNPs. In addition, in comparision with the crystal violet (CV)’ SERS response on GQDsx and AuNPs/G6/GQDsx substrate, it was indicated that the electromagnetic fields effect of AuNPs/G6/GQDsx was also closely related to the surafce state of GQDs. Moreover, the synergetic effect of AuNPs with GQDsx was beneficial to improve the SERS response of AuNPs/G6/GQDsx substrate.

To obtain efficient photocatalysts by coupling architectures, developing novel materials and elucidating the charge transport mechanism at the semiconductor interface are vital. Herein, a special nanocomposite (TiO2 microsphere/CuNPs/THPP) for photocatalytic hydrogen production was facilely fabricated with copper nanoparticles (CuNPs) as the interfacial linker of the TiO2 microspheres and meso-tetra(p-hydroxypheny)porphyrin (THPP). The assembly mode of the nanocomposite was studied in detail. It was found that the CuNPs implanted at the interface of the TiO2 microspheres and THPP can dramatically strengthen the interaction between the TiO2 microspheres and THPP, and improve the separation and transfer of photo-produced charges. Therefore, the nanocomposite displayed excellent performance for photocatalytic hydrogen production. Moreover, by recycling hydrogen production, it is demonstrated that the nanocomposite was a highly efficient and long-term stable photocatalyst. By investigating the energy band location and the charge transfer, the photocatalytic mechanism over the special nanocomposite was explored and proposed to explain the better activity of the TiO2 microsphere/CuNPs/THPP photocatalytic system. It will be helpful to provide deep insights into the construction of efficient photocatalytic systems.