Porous Rod-like NiTiO3-BiOBr Heterojunctions with Highly Improved Visible-Light Photocatalytic Performance.

NiTiO3-BiOBr heterostructured photocatalysts were constructed via precipitation, calcination and hydrothermal treatments. Various characterizations demonstrated that BiOBr nanosheets were decorated on NiTiO3 nanoparticals, forming porous rod-like heterojunctions. Compared with independent NiTiO3 and BiOBr, the composites with optimal BiOBr content presented highly improved visible-light photocatalytic efficiency. The degradation rates of Rhodamine B (RhB) and tetracycline (TC) reached 96.6% in 1.5 h (100% in 2 h) and 73.5% in 3 h, which are 6.61 and 1.53 times those of NiTiO3, respectively. The result is an improved photocatalytic behavior from the formation of heterojunctions with a large interface area, which significantly promoted the separation of photogenerated carriers and strengthened the visible-light absorption. Based on the free radical capture experiments and band position analysis, the photodegradation mechanism of type-II heterojunction was deduced. This study provides a new way to fabricate highly efficient NiTiO3-based photocatalysts for degrading certain organics.

Fabrication of Noble-Metal-Free Mo2C/CdIn2S4 Heterojunction Composites with Elevated Carrier Separation for Photocatalytic Hydrogen Production.

Molybdenum-based cocatalyst being used to construct heterojunctions for efficient photocatalytic H2 production is a promising research hotspot. In this work, CdIn2S4 was successfully closely supported on bulk Mo2C via the hydrothermal method. Based on their matching band structures, they formed a Type Ⅰ heterojunction after the combination of Mo2C (1.1 eV, -0.27 V, 0.83 V) and CdIn2S4 (2.3 eV, -0.74 V, 1.56 V). A series of characterizations proved that the heterojunction composite had higher charge separation efficiency compared to a single compound. Meanwhile, Mo2C in heterojunction could act as an active site for hydrogen production. The photocatalytic H2 production activity of the heterojunction composites was significantly improved, and the maximum activity was up to 1178.32 µmmol h-1 g-1 for 5Mo2C/CdIn2S4 composites. 5Mo2C/CdIn2S4 heterojunction composites possess excellent durability in three cycles (loss of 6%). Additionally, the mechanism of increased activity for composites was also investigated. This study provides a guide to designing noble-metal-free photocatalyst for highly efficient photocatalytic H2 evolution.

Novel noble-metal-free Co2P/CdIn2S4 heterojunction photocatalysts for elevated photocatalytic H2 production: Light absorption, charge separation and active site.

Constructing heterojunctions is an effective and controllable approach that can boost the activity of photocatalysts. Inspiringly, this study explored a simple method that can be used to construct novel noble-metal-free Co2P/CdIn2S4 (CPCIS) heterojunction photocatalysts for photocatalytic hydrogen production. The heterojunction was formed by loading CdIn2S4 (CIS) nanoparticles on the surface of Co2P (CP). The structure, morphology, and optical property of the as-prepared samples were characterized by a series of tests. The DRS results showed that, the light absorption range of CPCIS was extended to the full visible light range and its light absorption intensity obviously was enhanced at 500-800 nm. The PL and photoelectrochemical tests manifested that the formed heterojunction promoted the separation of charges. The LSV results indicated that CP reduced the H2 evolution overpotential of the composites. Besides, CP could serve as active sites of H2 evolution in heterojunction composites. Interestingly, the H2-evolution rate for the optimum CPCIS (471.87 µmol h-1 g-1) was around 3.6 times than CIS-Pt. The elevated activity of CPCIS may mainly attribute to the following aspects: its enhanced light absorption, elevated charge separation and increased active site. More importantly, the photocatalytic activity of heterojunction composites didn't almost decrease after three cycles. This article delivers an idea that can be applied to form heterojunctions between CP and other sulfides for photocatalytic H2 production, easily extending to other transition metal phosphides.

A novel noble-metal-free Mo2C-In2S3 heterojunction photocatalyst with efficient charge separation for enhanced photocatalytic H2 evolution under visible light.

Currently, designing novel noble-metal-free photocatalysts with efficient carriers migration and catalytically active sites have been a researching hotspot in photocatalytic hydrogen evolution. In this paper, a novel noble-metal-free Mo2C-In2S3 heterojunction was synthesized by a simple hydrothermal method. Morphology characterization revealed In2S3 was attached to Mo2C. Electrochemical results showed Mo2C improved the interface conductivity, and promoted the transportation of photogenerated carriers. Under visible light, the optimal Mo2C-In2S3 composite achieved a H2 generation rate of 535.58 µmol h-1 g-1, which was 175.6 and 25.8 times higher than pristine In2S3 (3.05 µmol h-1 g-1) and In2S3-1% Pt (20.73 µmol h-1 g-1). In addition, a reasonable mechanism of the elevated photocatalytic activity was also discussed. This study demonstrates commercial Mo2C has an important effect of separating carriers and replacing Pt as co-catalyst in heterojunctions. This research also provides a method to design and synthesize new noble-metal-free photocatalysts for excellent hydrogen production activity.

Aqueous leaching of lithium from simulated pyrometallurgical slag by sodium sulfate roasting.

In the pyrometallurgical treatment for spent lithium-ion batteries (LIBs), lithium is generally present in slag with Al, Ca and Si and is hard to be further treated. In this study, lithium was recovered from a simulated pyrometallurgical slag (pyro-slag) via sodium roasting and water leaching. The thermodynamic process for the reactions between slag and additives such as NaCl, NaNO3 and Na2SO4 were simulated during roasting by the HSC software, where Na2SO4 possessed stronger chemical reactivity. The optimal conditions for roasting were experimentally determined to be 800 °C for 60 min and an Na2SO4/Li molar ratio of 3 : 1, followed by water leaching at 70 °C for 80 min using a liquid-to-solid (L/S) mass ratio of 30 : 1. This yielded a maximum of 93.62% lithium recovery. The mechanism by which insoluble lithium in slag was transformed into soluble lithium by salt roasting was proposed using the analysis of XRD and EDS spectra, in which ion exchange occurred between Na+ and Li+ at a certain temperature.

Transition metal-doped amorphous molybdenum sulfide/graphene ternary cocatalysts for excellent photocatalytic hydrogen evolution: Synergistic effect of transition metal and graphene.

Though amorphous molybdenum sulfide (MoSx) is considered a promising H2 evolution cocatalyst, its intrinsic activity and charge transfer efficiency are still unsatisfactory. To overcome these drawbacks, transition metal-doped (Fe, Co, or Ni) amorphous MoSx/graphene ternary nanocomposites were designed and fabricated using a one-step solvothermal method. Their structure, morphology, and properties were characterized. The metal-doped MoSx nanoparticles were well distributed on the graphene sheets in the ternary composites. Metal doping greatly enhanced the intrinsic activity of amorphous MoSx, and the integration of graphene notably promoted the separation of photoinduced carriers. The photocatalytic H2 evolution with amorphous MoSx as cocatalyst has been substantially improved under the synergistic effect of the transition metal and graphene. The H2 evolution rate of Co-doped amorphous MoSx/graphene composites reached 11.45 mmol·h-1·g-1 at the Co:Mo molar ratio of 2:3, which is 64% higher than that of Co-doped MoSx, 21 times that of undoped MoSx/graphene, and 127 times that of pure MoSx. This study would supply an efficient strategy and a new vision for developing excellent noble-metal-free photocatalysts for photocatalytic hydrogen production.

A systematic approach to measure the contents of mono- and di-sulfonates in petroleum sulfonates by the novel method of acid-base titration coupled with traditional two-phase titration.

Petroleum sulfonates are broadly employed to increase the oil recovery efficiency in tertiary recovery, while the content of di-sulfonates in petroleum sulfonates is a critical factor in the flushing efficiency, because it adversely impacts the decrease of oil-water interfacial tension. Thus far, no methods have been considered convenient and reliable to determine the contents of mono- and di-sulfonates besides the traditional extraction method. This study established a simple and practical approach of acid-base titration coupled with traditional two-phase titration to measure the contents of mono- and di-sulfonates in petroleum sulfonates. To judge the reliability of the approach, the actives of petroleum sulfonates were separated into mono- and di-sulfonates using the traditional extraction method, the separation effect of which was confirmed using infrared spectroscopy and main elemental analysis. As the results demonstrated, all the contents of di-sulfonates in four petroleum sulfonates measured by the acid-base titration method are similar to those found by the extraction method. The contents of di-sulfonates (%) in four petroleum sulfonate samples were measured by comparing acid-base titration with the extraction method; respectively they were 8.57/8.19, 5.67/5.98, 5.61/5.35 and 2.37/2.15; the relative error of the measured di-sulfonates is about 6%, which satisfies the titration accuracy of petroleum sulfonates. In parallel experiments, the results of five acid-base titrations are very close, and the precision of the acid-base titration method was about 3%. Accordingly, this systematic approach by combining the new acid-base titration and traditional two-phase titration is of great significance to develop the evaluation system of petroleum sulfonates.

[Preparation and catalytic activity of surface-modification CNTs/TiO2 composite photocatalysts].

A novel kind of carbon nanotubes/titanium dioxide (CNTs/TiO2) composite photocatalyst was prepared by a modified sol-gel method in which the nanoscaled TiO2 particles were uniformly deposited on the CNTs modified with poly(vinyl pyrrolidone) (PVP). The composites were characterized by a range of analytical techniques including high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show the successful covering of the CNTs with PVP, forming core-shell structure. The nanoscaled TiO2 particles were uniformly deposited on the surface of CNTs reducing the bare CNTs which avoid losing the absorption and scattering of photons. The combination of CNTs and TiO2 particles imply the enhanced interactions between the CNTs and TiO2 interface which possibly becomes heterojunction. The composites become mesoporous crystalline TiO2 (anatase) clusters after annealing at 500 degrees C, and the surface area increases obviously. The photocatalytic activities of surface modification CNTs/TiO2 (smCNTs/TiO2) composites are extremely enhanced from the results of the photodegradation of methylene blue (MB).

[Antioxidant activity and spectroscopic behavior study with DNA of several Salen Mn(II), Eu(III) complexes].

Five kinds of Salen Mn(II) and two kinds of Eu(III) complexes were synthesized. Under the system of NBT/L-methionine, which creates and detects O2*-, the complexes of antioxidant activity were studied, and the conclusion revealed that all Mn(II) complexes have obvious antioxidant activity. The fluorescence study indicated that all the Salen metal complexes could bind with DNA, which shows their potential anticancer activity.