S­scheme heterojunction of thin-layer O-modified graphitic carbon nitride/cobalt porphyrin to promote photocatalytic CO2 conversion.

The emissions of CO2 are increasing year by year, which have led to serious environmental problems. Converting CO2 into valuable fuels through photocatalysis is a promising strategy. In this research, oxygen atoms were successfully innovated into graphitic carbon nitride (CN). Additionally, cobalt porphyrin (CoTPP) was successfully loaded onto the modified carbon nitride (Co/CN). The generation of interfacial electric fields and bending bands between CN and CoTPP was demonstrated experimentally. The electrons in the CN and the holes in the CoTPP were combined to form a unique S-scheme heterojunction structure, and efficient separation of carriers was promoted. As a result, the CO conversion under visible light irradiation reached an impressive 100.70 µmol g-1 h-1. By integrating theoretical and experimental findings, this study underscores the critical role of catalyst design in enabling efficient photocatalytic CO2 reduction.

Oxygen vacancy regulation strategy in V-Nb mixed oxides catalyst for enhanced aerobic oxidative desulfurization performance.

Bimetallic oxide is a potential catalyst for oxidative desulfurization of fuel. Thus, an appropriate method is needed to improve its catalytic performance. Manufacturing defect is an effective means. In this contribution, an oxygen vacancies (OVs) regulation strategy for enhancing the catalytic activity of bimetallic oxide is proposed. Density functional theory (DFT) calculations show that the crystal phase has a huge influence on the generation energy of oxygen vacancies, so a series of V-Nb mixed oxide with different crystal phases are synthesized. Detailed characterizations show that the as-prepared tetragonal V-Nb mixed oxide (T-VNbOx) has lower OVs formation energy and larger OVs concentration (compared to orthorhombic V-Nb mixed oxides, O-VNbOx). Owing to the activation of OVs, the catalytic activity of T-VNbOx was significantly enhanced to form ultra-deep oxidative desulfurization. In addition, T-VNbOx can be cycled eight times without significantly degrading the desulfurization performance.

Combined removal of SO3 and HCl by modified Ca(OH)2 from coal-fired flue gas.

As treatments for mainstream pollutants in coal-fired power plants have been established, the control of non-conventional pollutants, such as SO3 and HCl, is gradually gaining attention. In this study, combined SO3 and HCl removal is proposed based on SO3 removal by absorber injection. However, it is challenging to selectively absorb SO3 and HCl from SO2-rich atmospheres. Therefore, Ca(OH)2 was modified via ball milling and doping with CuO for the combined removal of SO3 and HCl. The results showed that ball milling reduced the particle and grain sizes of Ca(OH)2, which increased the active sites of Ca(OH)2 and prolonged reaction time. After modification by ball milling, SO3 absorption per mg of Ca(OH)2 increased by 40 %. However, HCl removal efficiency was difficult to improve by modifying Ca(OH)2 using only ball milling under SO3 and SO2 atmospheres. Therefore, the dechlorination capacity of Ca(OH)2 was improved by adding ions during the ball milling process. Doping of Ca(OH)2 with Cu2+ changed its crystal structure, weakened the diffusion resistance of HCl, and improved Ca(OH)2 utilization. Additionally, it increased the energy of Ca(OH)2 to adsorb HCl.

C-O band structure modified broad spectral response carbon nitride with enhanced electron density in photocatalytic peroxymonosulfate activation for bisphenol pollutants removal.

Here, a simple one-step calcination method uses glycolic acid (GA) and urea to synthesize C-O band structure modified carbon nitride with broad spectral response, which is used to construct a peroxymonosulfate/visible light (PMS/vis) system. The solid-state 13C NMR proved that C-O band structure was successfully introduced into the carbon nitride. Density functional theory (DFT) calculation show that the introduction of C-O band structure shortens the band gap of 0.05 g GA modified CN (0.05 GA-CN). Besides, Ultraviolet photoelectron spectroscopy (UPS) further illustrate that the 0.05 GA-CN has a higher charge density and promotes the degradation of pollutants. In PMS/vis system, 0.05 GA-CN can completely degrade bisphenol A (BPA) within 36 min. In addition, 0.05 GA-CN can also degrade bisphenol E (BPE) and bisphenol F (BPF). The cyclic voltammetry (CV) curve show that the introduction of C-O band structure enhances the activation ability of PMS. At the same time, 0.05 GA-CN/PMS has enhanced the activity of degrading BPA under blue light (450-462 nm), green light (510-520 nm) and red light (610-625 nm). This research provides a new method to synthesize carbon nitride with enhanced electron density for degradation of bisphenol pollutants in PMS/vis system.

Ultrathin structure of oxygen doped carbon nitride for efficient CO2photocatalytic reduction.

Photocatalytic conversion of carbon dioxide into fuels and valuable chemicals is a promising method for carbon neutralization and solving environmental problems. Through a simple thermal-oxidative exfoliation method, the O element was doped while exfoliated bulk g-C3N4into ultrathin structure g-C3N4. Benefitting from the ultrathin structure of g-C3N4, the larger surface area and shorter electrons migration distance effectively improve the CO2reduction efficiency. In addition, density functional thory computation proves that O element doping introduces new impurity energy levels, which making electrons easier to be excited. The prepared photocatalyst reduction of CO2to CO (116µmol g-1h-1) and CH4(47µmol g-1h-1).

Realizing the synergistic effect of electronic modulation over graphitic carbon nitride for highly efficient photodegradation of bisphenol A and 2-mercaptobenzothiazole: Mechanism, degradation pathway and density functional theory calculation.

Here, we successfully synthesized a brown carbon nitride (CY-C3N4) co-modified with oxygen bridge and porous defects via a universal acylation method. Excitingly, density functional theory (DFT) calculation shows that the introduction of oxygen bridges in the calcination polymerization process can adjust the electronic structure and energy band position of the new material. Further, the results of elemental analysis and X-ray photoemission spectroscopy test indicate that the oxygen bridge structure was successfully introduced into the skeleton of carbon nitride. The results show that 0.1CY-C3N4 can remove bisphenol A (BPA) and 2-mercaptobenzothiazole (MBT) with a removal rate of approximately 99% in 90 min and 20 min, respectively. Its degradation rate is 17.94 times and 3.85 times faster than that the original carbon nitride, respectively. Further, through HPLC-MS analysis, the intermediate products of the reaction process were analyzed in depth to propose a possible photocatalytic degradation route. Free radical capturing test and ESR spectroscopy indicate that the formative hydroxyl radical (OH), superoxide radical (O2-), singlet oxygen (1O2) and hole (h+) all play a key role in the photodegradation. This study provides a new way to synthesize brown carbon nitrides with oxygen bridges and porous defects for environmental applications.

An efficient broad spectrum-driven carbon and oxygen co-doped g-C3N4 for the photodegradation of endocrine disrupting: Mechanism, degradation pathway, DFT calculation and toluene selective oxidation.

In this study, a new type of carbon and oxygen co-doped g-C3N4 (PACN) was successfully synthesized by a one-step thermal polymerization method for the photodegradation of Bisphenol A (BPA) and selective oxidation of toluene to benzaldehyde. The degradation rate of BPA was 23.58 times higher than that of pristine g-C3N4 and the efficiency benzaldehyde formation rate without the need of any solvent increased to 5.43 times that of g-C3N4. At the same time, the band structure calculation of its simulated structure is performed by DFT, which shows that the introduction of oxygen linking band can adjust its band structure and obtain a smaller band gap. In addition, the PACN displays an enhanced photocatalytic degradation of BPA under the long wavelength (λ ≥ 550 nm) and NIR light irradiation (λ ≥ 760 nm), which indicates that the synthesized materials have a broad spectrum of photocatalytic activity. According to the results of secondary ion mass spectrometry (SIMS) and nuclear magnetic resonance spectroscopy (NMR), C atoms and O atoms were introduced into the original g-C3N4 skeleton. In addition, the intermediate products were detected by mass spectrometry (HPLC-MS), and the BPA degradation pathway was proposed. A feasible photocatalytic reaction mechanism was also proposed.

Porous defective carbon nitride obtained by a universal method for photocatalytic hydrogen production from water splitting.

For the first time, herein this work, we have developed an effective and adaptable method to introduce defects onto the polymeric carbon nitride by simply grinding urea with urea nitrate which resulting new carbon nitride composite (UNU-C3N4) and melamine with urea nitrate which resulting new carbon nitride composite (UNM-C3N4). The UNU-C3N4 reveals high performance towards photocatalytic hydrogen production and as well as photocatalytic removal of contaminants. The results confirm that the defects enhanced the specific surface area, and improved performance of adsorbed oxygen which beneficial to generate more active radicals and more conducive sties to improve d the overall photocatalytic performance. The high N, H, and O content-enhanced electron polarization effects, by introducing the additional N, H, and O atoms into the g-C3N4 matrix, which will increase the charge transfer rate and charge separation efficiency. At the same time, the results of ESR also expression that the new type of as-prepared carbon nitride samples exhibit abundant of hydrogen radical (H) formation, which is also assist to improve the photocatalytic hydrogen production performance. As expected, the H2 evolution rate of UNU-C3N4(or UNM-C3N4) underneath simulated solar light irradiation is 9.93 times (13.76 times) than that of U-C3N4 (urea as raw material) (or M-C3N4 (melamine as raw material)). The high hydrogen evolution rates of UNU-C3N4 and UNM-C3N4 are 830.94 and 556.79 µmol g-1  h-1 under the visible-light irradiation, respectively. Meanwhile, the synthesized UNU-C3N4 and UNM-C3N4 material are demonstrated an efficient ability to degrade pollutants. In general, this work provides a viable way to introduce defects and hydrogen bands into the structure of carbon nitride.

Mechanical exfoliation of boron carbide: A metal-free catalyst for aerobic oxidative desulfurization in fuel.

Metal-free catalysts have been proved to be a low-cost and environmentally friendly species in aerobic oxidative desulfurization (ODS). In this work, exfoliated metal-free boron carbide with few-layered structure, small size, and abundant defects, was first employed in an aerobic ODS system for ultra-deep desulfurization. The exfoliation process was realized by employing a planetary ball mill strategy. Detailed characterizations showed that the ball milling process not only induces thinner layers and small sizes but also introduces numerous defects into the boron carbide catalysts, which is vital in metal-free catalysis. Furthermore, the exfoliated boron carbide catalyst was applied in aerobic ODS system, and 99.5 % of sulfur removal was obtained. Moreover, the catalyst can be recycled 17 times without a significant decrease in catalytic activity. In particular, it was found that ∼90 % of the sulfur compounds in real diesel oil could be removed by the current aerobic ODS system.

Lattice-Refined Transition-Metal Oxides via Ball Milling for Boosted Catalytic Oxidation Performance.

Surface oxygen vacancy can greatly affect the properties of transition-metal oxides. However, engineering oxygen vacancy-abundant transition-metal oxides with high specific surface area (SSA) remains challenging. At present, the generation of oxygen vacancies in metal oxides is time-consuming and less environmentally friendly by chemical leaching methods that usually require additional waste treatment. Herein, a series of oxygen vacancy-abundant transition-metal oxides with high SSA are constructed via a lattice refining strategy. This strategy is realized by urea-assisted ball milling pyrolysis and is green, efficient, and universal. The oxygen vacancies promote the mobility of oxygen, leading to a boosted catalytic oxidation performance of aromatic sulfides. Such a strategy provides an efficient approach to manufacturing oxygen vacancies on transition-metal oxides, which may be beneficial for various related applications as an effective catalytic material.

Magnetic mesoporous nanospheres supported phosphomolybdate-based ionic liquid for aerobic oxidative desulfurization of fuel.

Phosphomolybdate-based ionic liquid [(C8H17)3NCH3]3PMo12O40 was prepared and supported on a magnetic mesoporous silica (γ-Fe2O3@SiO2@mSiO2) to obtain a magnetic mesoporous catalyst. The morphology and components of the catalyst were characterized by FT-IR, XRD, XPS, SEM, TEM, nitrogen adsorption-desorption isotherms, and VSM. With air as oxidant, the catalyst showed perfect desulfurization performance in oxidation of dibenzothiophene (DBT). The removal of DBT from model oil could reach 100% within 5 h at 120 °C. After reaction, the catalyst could be separated by a magnet and recycled at least four times without obvious decrease in the catalytic performance.

Synthesis of zinc ferrite/silver iodide composite with enhanced photocatalytic antibacterial and pollutant degradation ability.

ZnFe2O4/AgI composites were first prepared successfully with a hydrothermal method, and ZnFe2O4 nanoparticles were uniformly decorated on the surface of AgI particles. The photocatalytic activities of the obtained ZnFe2O4/AgI composites were investigated by the degradation of organic pollutants and the inactivation of bacteria under visible light irradiation. The results showed that the introduction of ZnFe2O4 greatly enhanced the light harvesting ability and improved the separation efficiency of the photogenerated charge carriers, which contributed to the enhanced generation of reactive species and thus promoted the photocatalytic performance. The 5% ZnFe2O4/AgI composite exhibited the optimal photocatalytic disinfection of E. coli (100% removal efficiency in 80 min) as well as the photocatalytic degradation of rhodamine B (RhB) (98.5% removal rate in 40 min). Furthermore, four consecutive cycles also demonstrated the stable photocatalytic activity of the as-prepared ZnFe2O4/AgI composites. In addition, H2O2 was identified as the predominant active species in the photocatalytic inactivation of bacteria. This study indicated that ZnFe2O4/AgI composites are a promising candidate for the treatment of wastewater.

Tuning electronic properties of boron nitride nanoplate via doping carbon for enhanced adsorptive performance.

In this paper, the carbon-doped boron nitride nanoplate (C-BNNP) was prepared by pyrolyzing the precursor under N2 and served as an excellent adsorbent for removal of Rhodamine B (RhB). The structure and composition of C-BNNP were characterized and its adsorption behavior for RhB was investigated. Compared with boron nitride nanoplate (BNNP) which was synthesized under NH3, C-BNNP displayed an enhancement of the adsorption capacity for RhB (833mg/g). The adsorption activity was comprehensibly studied by kinetics, isotherm and thermodynamics. The adsorption kinetics followed pseudo-second-order model. The equilibrium adsorption data agreed well with the Langmuir isotherm. And the thermodynamics indicated that the adsorption process was a spontaneous, exothermic and physisorption process. In addition, the density functional theory was proposed that doping carbon in the BNNP decreased the chemical hardness of the adsorbent and enhanced the adsorption capacity of C-BNNP for RhB.

Novel AgI-decorated ß-Bi2O3 nanosheet heterostructured Z-scheme photocatalysts for efficient degradation of organic pollutants with enhanced performance.

The low photocatalytic activity of single semiconductor photocatalysts mainly originates from their fast recombination of photogenerated electron-hole pairs. Constructing nanosheet-based composite photocatalysts is an effective way to enhance the charge separation efficiency of photogenerated electron-hole pairs. In this work, AgI-decorated ß-Bi2O3 nanosheet heterostructured photocatalysts were prepared by a facile method. The as-obtained AgI/ß-Bi2O3 heterostructures exhibited enhanced visible-light-driven photocatalytic activity towards the degradation of methyl orange (MO) and tetracycline hydrochloride (TC) in aqueous solution. The optimum photocatalytic activity of 20%-AgI/ß-Bi2O3 for the degradation of MO was about 4.1 and 6.2 times higher than that of AgI and ß-Bi2O3. The photocatalytic activity enhancement of AgI/ß-Bi2O3 heterostructures could be ascribed to the formation of a Z-scheme system, which results in the efficient space separation of photo-induced charge carriers.

Facile fabrication and enhanced visible light photocatalytic activity of few-layer MoS2 coupled BiOBr microspheres.

Novel sphere-like MoS2/BiOBr composites were prepared by a facile ethylene glycol (EG)-assisted solvothermal process in the presence of the ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C16mim]Br). A nanostructured heterojunction, with few-layer MoS2 deposited on the surface of BiOBr microspheres, was constructed. During the synthetic process, the ionic liquid acted as a reactant, a template and a dispersing agent at the same time, leading to the formation of few-layer MoS2 dispersed on the surface of BiOBr microspheres. The MoS2/BiOBr composites exhibited much higher visible light photocatalytic activity towards rhodamine B (RhB) photodegradation than pure BiOBr. 3 wt% MoS2/BiOBr possessed the optimal photocatalytic activity, which was approximately 2.5 times as high as that of pure BiOBr. Through multiple characterization techniques, the relationship between the specific structure and the admirable photocatalytic activity of the MoS2/BiOBr microspheres was investigated. The critical role of the few-layer MoS2 in the MoS2/BiOBr microspheres was explored. A photocatalytic mechanism for the MoS2/BiOBr composites was also proposed.

α-Fe2O3 cubes with high visible-light-activated photoelectrochemical activity towards glucose: hydrothermal synthesis assisted by a hydrophobic ionic liquid.

A liquid/liquid interfacial reaction system was designed to fabricate α-Fe2O3 cubes. The reaction system uses a hydrophobic ionic liquid containing iron ions ([(C8H17)2(CH3)2N]FeCl4) for manufacturing α-Fe2O3 cubes by a novel and environmentally friendly hydrothermal method under low-temperature conditions (140 °C). The iron-containing ionic liquid is hydrophobic and can form a liquid/liquid interface with water, which is vital for fabrication of the α-Fe2O3 cubes. Nanomaterials synthesized from hydrophobic iron-containing ionic liquids show good crystallinity, well-developed morphology, and uniform size. The effect of different ionic liquids on the morphology of α-Fe2 O3 was investigated in detail. [(C8H17)2(CH3)2N]FeCl4 is assumed to perform the triple role of forming a liquid/liquid interface with water and acting as reactant and template at the same time. The effect of the reaction temperature on the formation of the α-Fe2O3 cubes was also studied. Temperatures lower or higher than 140 °C are not conducive to formation of the α-Fe2O3 cubes. Their photoelectrochemical properties were tested by means of the transient photocurrent response of electrodes modified with as-prepared α-Fe2O3 cubes. The photocurrent response of an α-Fe2O3 cubes/indium tin oxide electrode is high and stable, and it shows great promise as a photoelectrochemical glucose sensor with high sensitivity and fast response, which are beneficial to practical applications of nanosensors.

Ionic liquid assisted synthesis and photocatalytic properties of α-Fe2O3 hollow microspheres.

α-Fe2O3 hollow microspheres have been successfully prepared in the presence of metal ion-containing reactable ionic liquid 1-octyl-3-methylimidazolium tetrachlorideferrate(III) ([Omim]FeCl4) under the solvothermal condition. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), FT-IR spectrum, and diffuse reflectance spectroscopy (DRS). The effect of concentration of ionic liquids on the morphology of α-Fe2O3 had been investigated in detail. It was found that [Omim]FeCl4 acted not only as Fe source but also as solvent and template for the fabrication of α-Fe2O3 hollow microspheres. In addition, the electrochemical and photocatalytic properties of α-Fe2O3 were investigated. The α-Fe2O3 hollow microspheres exhibited high conductivity, high photocurrent, and high photocatalytic activity. The designed hollow microsphere showed potential applications in photocatalysis.

[Study on adductive reaction of Ni[(C4H9O)2PS2]2 with nitrogen base by spectrophotometric method(II)].

Reaction of Ni[(C4H9O)2PS2]2 with ethylamine, n-propylamine, n-butylamine, and n-amylamine have been studied by spectrophotometry in ethanol at 30 degrees C. For nitrogen base(B), the adduct formation of NiL2.B and NiL2.B2 is established, and their additive equilibrium constants (lg beta n) and molecular number (n) have been discussed. All the NiL2.B and NiL2.B2 complexes exhibit virtually the same electronic spectra arising from the five-coordinate NiNS4 and six-coordinate NiN2S4 chromophore respectively. The constants (lg beta n) increase with basicity (pKa) of nitrogen base and can be described by experimental formulas: lg beta 1 = -9.69 +1.15 pKa; lg beta 2 = -18.73 +2.28 pKa.