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The g-C3N4@ZnIn2S4 heterostructures were successfully synthesized through a combination of thermal annealing and hydrothermal methods. To enhance the photocatalytic hydrogen production performance and explore the interface between charge carriers, heterostructures of g-C3N4@ZnIn2S4 were fabricated using varying weights of g-C3N4 nanostructures under visible light irradiation. Remarkably, the photocatalytic hydrogen production efficiency of g-C3N4@ZnIn2S4 heterostructures with 0.01 g g-C3N4 nanostructures was significantly improved, showing approximately 228.6 and 2.58 times higher than that of g-C3N4 nanostructures and ZnIn2S4 nanostructures, respectively. This enhancement in photocatalytic performance is attributed to the effective utilization of visible light and the efficient separation of photogenerated electron-hole pairs facilitated by the heterojunction structures. Moreover, the reusability test validated the outstanding performance of g-C3N4@ZnIn2S4 heterostructures, as they maintained high photocatalytic hydrogen production even after undergoing eight cycles without any noticeable decrease in efficiency. This study offers a promising strategy for designing and synthesizing an environmentally friendly g-C3N4@ZnIn2S4 heterojunction with potential applications in photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4), W-doped BiVO4 (BiVO4:W), and Mo-doped BiVO4 (BiVO4:Mo) nanoparticles were synthesized at pH = 4 using a green hydrothermal method. The effects of 2 at% W or Mo doping on the microstructural and optical characteristics of as-prepared BiVO4 nanoparticles and the effect of combining particle morphology modification and impurity dopant incorporation on the visible-light-derived photocatalytic degradation of dilute Rhodamine B (RhB) solution are studied. XRD examination revealed that these obtained BiVO4-based nanoparticles had a highly crystalline and single monoclinic phase. SEM and TEM observations showed that impurity doping could modify the surface morphology, change the particle shape, and reduce the particle diameter to enlarge their specific surface area, increasing the reactive sites of the photocatalytic process. XPS and FL measurements indicated that W- and Mo-doped nanoparticles possessed higher concentrations of oxygen vacancies, which could promote the n-type semiconductor property. It was found that the BiVO4:W and BiVO4:Mo powder samples exhibited better photocatalytic activity for efficient RhB removal than that shown by pristine BiVO4 powder samples under visible light illumination. That feature can be ascribed to the larger surface area and improved concentration of photogenerated charge carriers of the former. [ABSTRACT FROM AUTHOR]

The Au@CdS nanocomposites have been synthesized using a combination of wet chemical and hydrothermal approaches at lower reaction temperatures. The concentrations of CdS precursors and reaction temperature can be essential in influencing photocatalytic water splitting under blue-LED light excitation. The optimized Au@CdS nanocomposites (5 mM CdS precursors and 100 °C) exhibited the highest hydrogen evolution rate of 1.041 mmolh−1 g−1, which is 175.3 times higher than CdS nanoparticles for de-ionized water under blue-LED light excitation. This result is ascribed to separate photogenerated charge carriers and increased light absorption by the Au core. The Au@CdS nanocomposites (1.204 mmolh−1 g−1) revealed significant applications in photocatalytic tap water splitting under blue-LED light excitation, which is 512.3 times higher than CdS nanoparticles. In addition, reusability experiments demonstrate that Au@CdS nanocomposites exhibit excellent stability for the long-term photocatalytic tap water splitting process. Furthermore, this research shows that Au nanoparticles decorated with CdS shells effectively achieve high-efficiency conversion from light to hydrogen energy. [ABSTRACT FROM AUTHOR]

In the present work, we described the synthesis and characterization of the ternary Cu2O/CuS/ZnS nanocomposite using a facile two-step wet chemical method for blue LED-light-induced photocatalytic hydrogen production. The concentrations of the ZnS precursor and reaction time were essential in controlling the photocatalytic hydrogen production efficiency of the Cu2O/CuS/ZnS nanocomposite under blue LED light irradiation. The optimized Cu2O/CuS/ZnS nanocomposite exhibited a maximum photocatalytic hydrogen evolution rate of 1109 µmolh−1g−1, which was remarkably higher than Cu2O nanostructures. Through the cycle stability it can be observed that the hydrogen production rate of the Cu2O/CuS/ZnS nanocomposite decreased after 4 cycles (1 cycle = 3 h), but it remained at 82.2% of the initial performance under blue LED light irradiation. These reasons are mainly attributed to the introduction of CuS and ZnS to construct a rationally coupled reaction system, which enables the synergistic utilization of photogenerated carriers and the increased absorption of visible light for boosting blue LED-light-driven photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

In this study, we fabricated Er-doped ZnO/CuS/Au core-shell nanowires using two-step wet chemical methods and an ion-sputtering method on a glass substrate as a bifunctional photocatalytic and surface-enhanced Raman scattering (SERS) substrate. The characteristic properties of as-prepared photocatalysts were confirmed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, DR/UV-Vis spectroscopy, and photoluminescence spectroscopy. Compared with Er-doped ZnO nanowires and Er-doped ZnO/CuS core-shell nanowires, Er-doped ZnO/CuS/Au core-shell nanowires exhibited remarkably photocatalytic activity to degrade acid orange 7 solutions under blue LED light. These results ascribed to the Er-doped ZnO/CuS/Au core-shell nanowires can enhance the visible-light absorbance and the separation efficiency of photogenerated electron-hole pairs, inducing their higher photocatalytic activity under blue LED light. In addition, Er-doped ZnO/CuS/Au core-shell nanowires exhibit high sensitivity, a low detection limit (10−6 M), uniformity, recyclability, and stability of SERS performance for detected acid orange 7. [ABSTRACT FROM AUTHOR]

Cerium dioxide (CeO2, ceria), a promising and abundant catalytic material with high-efficiency, nontoxicity, photochemical stability, and affordability, can be used as a photocatalyst to photocatalytically degrade organics and split water for hydrogen production under ultraviolet (UV) irradiation (about 5% of solar energy). However, the applications of the CeO2 photocatalyst are limited due to low photocatalytic efficiency under sunlight irradiation. In this study, a nanosized CeO2 powder was prepared by the precipitation method. Subsequently, various amounts of polyaniline (PANI) nanoparticles were deposited onto the surface of the CeO2 nanoparticles to form a heterostructure by the polymerization method. The crystal structure, morphology, surface and optical properties of the CeO2/PANI nanoparticles were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis) absorption spectroscopy, and photoluminescence (PL). Experimental results demonstrated that PANI deposition improved the light absorption of CeO2 nanoparticles in the visible light region. The heterostructured CeO2/PANI nanoparticle with 4 wt % PANI deposition exhibited optimal photocatalytic activities with a hydrogen production rate of 462 μmolg−1 within 6 h and a methyl orange (MO) degradation rate of 45% within 4 h under visible light irradiation. The photocatalytic mechanisms of the composite powder are also proposed in this report. [ABSTRACT FROM AUTHOR]