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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 composite catalyst of crystalline Co(OH)2 modified rare-earth perovskite-type LaNiO3 was synthesized by physical precipitation-sol high temperature calcination method. The ratio between La/Ni and between Co(OH)2/LaNiO3 added presence obvious impact on hydrogen production performance. Under the illumination of the cut-off filter (≥ 420 nm), when the molar ratio between La/Ni is 2:1, the hydrogen production amount at 5 h reached 70.89 μmol. The hydrogen production of Co(OH)2/LaNiO3 under the optimal catalytic conditions was 4.5 times higher than of pure LaNiO3. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) showed good crystallinity of the sample and successful synthesis of the material. TEM and SEM were used to detect the appearance of the catalytic material. The Photoluminescence spectrum (PL), ultraviolet–visible spectroscopy (UV–Vis) and electrochemical workstations were used to characterize the catalytic performance, which is consistent with the hydrogen production results. It is indicated that the bulk Co(OH)2 acts as an electron collector in the catalytic process, which significantly increases the transfer rate of photoelectrons, enhance the hydrogen production performance. [ABSTRACT FROM AUTHOR]

It was the constant pursuit of researchers to explore catalysts with higher catalytic activity, and the use of co-catalysts to modify the performance of photocatalytic materials had a significant effect on charge separation. In this paper, the non-precious metal NiS-modified ZnCo2O4 composite catalytic material prepared by hydrothermal method had high-efficiency catalytic performance. When the weight ratio of NiS to ZnCo2O4 was 12%, the optimal catalytic activity is 3.57 mmol g−1 h−1, which was more than twice that of ZnCo2O4. The presence of NiS not only improved the specific surface area of the catalyst and its ability to respond to light, but the close interface formed by the combination of the two monomer phases accelerated the transfer and the utilization of the photocharge on ZnCo2O4 to NiS, thereby promoting the separation of electron holes and improving the photocatalytic activity of the catalyst. According to the research results, the mechanism of hydrogen production in the photocatalytic system was revealed. In this paper, NiS was used to modify the bimetallic oxide with cubic appearance, which provided a new strategy for the development of new photocatalysts. [ABSTRACT FROM AUTHOR]

The expansion of the optical response range and the high photoelectron holes separation and the transfer efficiency are prerequisites for the excellent hydrogen evolution performance of the catalyst. In this paper, amorphous CoSx is combined with rare-earth complex LaMnO3 and under the characterization of SEM, TEM, XRD and XPS, the successful synthesis of the composite catalyst was demonstrated; characterization results by UV–Vis, BET and electrochemical workstations show that the composite material exposes more active sites, and the close contact interface formed between the two effectively improves the separation and transmission of photogenerated carriers, and the ability of the composite material to sense light is also significantly enhanced. After optimizing the hydrogen production conditions of the composite catalyst, the hydrogen production under visible light (≥ 420 nm) for 5 h reached 458.8 μmol, which was about 6.8 and 4.5 times that of pure LaMnO3 and CoSx, and the hydrogen evolution stability of the material is very good. Studies have shown that amorphous CoSx is a good material that can replace precious metals for hydrogen production. [ABSTRACT FROM AUTHOR]

Sm2MoO6/Ni(OH)2 was successfully immersed in water first, and the sensitizer is Eosin Y and the sacrificial agent is triethanolamine agent for high-efficiency photocatalytic production of H2. When Sm2MoO6 was loaded onto the surface of Ni(OH)2, the photocatalytic activity (2407.48 μmol g−1 h−1) was 2.6 times that of Ni(OH)2 (925.36 μmol g−1 h−1), which was Sm2MoO6 (169.36 μmol g−1 h−1) is 14.2 times. From a series of characterizations, Sm2MoO6 is an effective cocatalyst to improve the separation of photo-generated charges and the efficiency of electron transfer. Large specific surface areas are a primary requirement for high efficiency catalysts, and the catalyst is sufficiently into contact with the sensitizer and the sacrificial agent to soar the photocatalytic activity. The first condition for an excellent catalyst is that it has a large specific surface area and can provide more active sites. In the dye sensitization system, the photocatalytic activity of Sm2MoO6/Ni(OH)2 is 2.6 times that of Ni(OH)2 and 14.2 times that of Sm2MoO6. Sm2MoO6 is an effective co-catalyst. [ABSTRACT FROM AUTHOR]

In this study, a CoS/NiMoO4 composite catalyst with good TYPE-II heterojunction was prepared by hydrothermal method with NiMoO4 nanorods, with water as a medium to load small amount of amorphous CoS, by changing the loading amounts of amorphous CoS. X-ray diffraction, UV–Visible diffuse reflection and other characteristics indicate that doped amorphous CoS can significantly improve the photocatalytic performance of NiMoO4, and the charge separation and electron transfer efficiency of composite catalysts detected by photoelectric chemistry are also significantly improved compared with NiMoO4. The photocatalytic activity and stability of the composite catalyst were studied by hydrogen evolution experiment. The hydrogen production rate of the composite catalyst can reach 338 μmol, which is 3.23 times higher than pure NiMoO4. This simple hydrothermal synthesis of photocatalytic materials provides new ideas and methods for the design and development of new composite photocatalysts. [ABSTRACT FROM AUTHOR]

A novel composite perovskite LaNiO3 photocatalyst modified by MoS2 was synthesized by sol-high temperature calcination. When the molar ratio of La/Ni was 2:1, MoS2 accounts for 3% of the MoS2/LaNiO3 composite catalyst. The hydrogen production activity is up to 47.1 μmol h−1. In the visible range (≥ 420 nm), the hydrogen generation of the composite photocatalyst is increased more than three times that of pure LaNiO3. It is described that the hydrogen production capacity of catalytic materials formed by MoS2-modified LaNiO3 is significantly improved under visible light, the electron and hole pairs are effectively separated, the electron transfer rate is increased, and the recombination of electron and hole pairs is reduced. Furthermore, the experimental results were measured by energy spectrum (XPS), X-ray diffraction (XRD), photoluminescence spectroscopy (PL), scanning electron microscope (SEM), UV–Vis transmission electron microscopy (TEM), and electrochemical workstation. This is consistent with the hydrogen production capacity of the catalyst. [ABSTRACT FROM AUTHOR]