The development of clean and renewable energy technologies is seen as the key to addressing energy and environmental issues.Oxygen evolution reaction (OER) plays key roles in storage intermittent energy,such as solar and wind,from water splitting.Recently, OER under neutral conditions receives considerable interests due to its environmental friendliness.However,the efficiency of OER under neutral environment is far below that under alkaline or acidic condition.In this review,the current researchers' understanding of the mechanism of OER under mild pH conditions is firstly outlined.Thereafter,several important characterisation techniques for in situ tracking of the electrocatalytic process of OER are presented,which is crucial to reveal the OER mechanism under neutral conditions.Moreover,an overview over catalytic materials towards neutral OER,including Co?,Ni?,and Mn?based catalysts,is provided.Finally,a brief outlook on the remaining challenges and possible strategies for promoting neutral OER is given.
With the rise of electric revolution and the establishment of "carbon dioxide emission and carbon neutrality" strategy, petroleum coke has got great development in value?added applications such as lithium cathode materials and high?grade prebaked anode.However,high value?added applications of petroleum coke all have strict requirements for sulfur content of petroleum coke. The high sulfur content in petroleum coke will have a negative impact on the high value application of petroleum coke.The research status of main desulphurization technologies of petroleum coke,including solvent extraction desulfurization technology,high temperature calcination desulfurization technology,oxidation desulfurization technology, alkali metal compound desulfurization technology,hydrodesulfurization technology,microbial desulfurization technology and process intensification auxiliary desulfurization technology are summarized.It was found that the desulphurisation rate of process?enhanced assisted desulphurisation could reach 93.6%,which could reduce the sulphur mass fraction in petroleum coke from 7.57% to 0.48%. The desulfurization technology of petroleum coke should maintain the principle that the structure of petroleum coke after desulfurization is not destroyed to the greatest extent.Therefore,oxidative desulfurization coupled process enhancement assisted desulfurization should have bright prospect in industrial application of petroleum coke desulphurization.
Paraffin is mainly composed of n?alkanes, small amounts of i?alkanes, cycloalkanes, aromatic hydrocarbons and trace amounts of S,N,O compounds. Under the action of ultraviolet light and heat, those compounds containing elements S,N,O,aromatic and unstable elements of alkene aromatic can be oxidated,resulting in a darker color and lower paraffin light stability.In order to explore the reasons for the deterioration of the paraffin light stability,the effects of internal factors such as nitrates,sulfides and oil content on the paraffin light stability were investigated.Orthogonal experiments were carried out to investigate the effects of ultraviolet absorbers,hindered amine light stabilizers,antioxidants and its compounding agent on the improvement of the paraffin light stability.The results showed that the best paraffin light stability was achieved when the additive amounts of UV absorbers, hindered amine light stabilizers and antioxidants in the compound were 300 μg/g, 300 μg/g and 300 μg/g, respectively.
A series of B?MFI zeolites were synthesized using a solvent?free method using tetrapropylammonium hydroxide (TPAOH) as a template. XRD, SEM, N2 adsorption desorption, in situ infrared spectroscopy, and pyridine adsorption infrared spectroscopy were used to characterize the effect of template agent addition on the physicochemical properties of B?MFI zeolites, and the performance of 1?butene double bond isomerization reaction was investigated. The results showed that the addition of template significantly affected the grain size and skeleton boron species content of B?MFI zeolites. When the template agent addition was 4.500 g (n（SiO2）/n（TPAOH)=11.6）, the B?MFI zeolites obtained had the smallest particle size and the largest number of silicon boron hydroxyl pits, providing more highly active reaction sites. The reaction evaluation results confirmed that when using B?MFI molecular sieve catalyst for the double bond isomerization of 1?butene, the conversion rate of 1?butene was as high as 70.00%, and the selectivity of 2?butene was greater than 99%. The catalyst had excellent stability and showed no signs of deactivation during the evaluation period.
Different morphology CeO2 was used as a catalyst to catalyse the synthesis of trimethylene carbonate from CO2 and 1,3?propanediol.The structure and composition of cerium oxides were characterized by SEM, TEM, XPS and XRD. The results showed that the yield of trimethylene carbonate was up to 72.5% at 130 ℃ for 4 h when using the rod?shaped cerium oxide as catalyst and 2?cyanopyridine as dehydrating agent. R?CeO2 has a higher number of defect sites and an suitable specific surface area, The average particle size is small and it has moderate number of Lewis acidic sites. Based on this, the substrate range was expanded, and the experimental results showed that both five?membered cyclic carbonates and six?membered cyclic carbonates could be obtained in good yields.
As a classic non?metallic semiconductor photocatalyst, graphite phase carbon nitride material （g?C3N4） has attracted widespread attention in recent years due to its stable physical and chemical properties, reasonable band structure, low cost, easy availability, safety, and pollution?free advantages. It has good application and development prospects in the fields of environmental protection, purification and energy catalysis. However, the utilization of g?C3N4 in studies is significantly hampered by its tiny specific surface area, limited absorption of visible light, and high rate of recombination of photogenerated electrons and holes. The basic structure, characteristics and main modifications of g?C3N4 are reviewed, covering modification means such as elemental doping, morphological modulation, noble metal deposition and the practical applications of g?C3N4 in recent years at home and abroad.
MoS2 quantum dots (QDs) have attracted a lot of attention lately due to their excellent fluorescence properties, catalytic activity, and good biocompatibility. There are various ways to prepare MoS2 QDs since its first preparation in 2010, including hydrothermal, ultrasonic, and etching methods. Even though other molybdenum?based quantum dots like MoP, Mo2C, Mo2N, and MoSe2 have shown great potential in various fields, their preparation methods have rarely been reported. In this article, The preparation methods and research status of these molybdenum?based quantum dots (MoO2/MoO3, MoP, Mo2C, Mo2N amd MoSe2) and comparing the advantages and limitations of different preparation methods were discussed. The key problems in the synthesis of these quantum dots and their application prospects in different directions were discussed.
The rare earth?transition metal complex [LaCu6（OH）3（ClO4）3（Gly）6（Im）6]（ClO4）2·3（MeOH） （Gly = glycine，Im = imidazole） has been synthesized by evaporation method.The complex crystallizes in the trigonal crystal system with the R3 space group，a=1.591 99（12） nm，b=1.591 99（12） nm，c=2.354 20（2） nm，α=β=90°，γ=120°.The coordination units of the complexes are extended into three?dimensional structures via various forms of hydrogen bonding.The properties of the complex were characterized by infrared analysis，thermogravimetric analysis，fluorescence analysis and magnetic analysis.The results showed that the weight loss process of the complex is roughly divided into three steps，and the complex shows great thermal stability.Three characteristic peaks were found in fluorescence emission spectrum of the complex，which indicates that the complex exhibits weak fluorescence.There is antiferromagnetic interaction between metal ions in the complex.
Perovskite photovoltaic cells are considered as the most promising third generation photovoltaic products due to their high photoelectric conversion efficiency and flexible processing while the high temperature encapsulation process of traditional encapsulation materials can hardly meet the demand of high performance of perovskite photovoltaic modules.In this paper, an adhesive film material by free radical co?polymerization process was successfully synthesized.Light transmission and bonding are characterized by infrared spectroscopy and tensile testing machine,confirming that the polymer is very suitable for chalcogenide photovoltaic cell encapsulation,and that the polymer can be effectively adhered to the chalcogenide solar cell and the outer layer of the glass at 80 ℃.The polymer is suitable for the encapsulation of chalcogenide photovoltaic cells.The photoelectric conversion efficiency of the encapsulated PSCs can reach 20.59%,and the encapsulated PSCs devices show good impact resistance.
The semiconductor, electroplating, metallurgy, and ceramic industries discharge high concentration fluoride containing wastewater, making fluoride pollution in natural water a global problem.Thus， Zn?Mg?Al LDO is a good adsorbent material. Under different reaction temperatures of n（Zn2+）/n（Mg2+）/n（Al3+）, Zn?Mg?Al LDH was synthesized by co?precipitation method, and Zn?Mg?Al?LDH was calcined at different temperatures to obtain Zn?Mg?Al?LDO. X?ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT?IR) and BET specific surface area testing methods were used to study the structure and properties of Zn?Mg?Al LDO. The adsorption experiment was conducted on 50 mL of NaF solution with an mass concentration of 20.0 mg/L to investigate the performance of Zn?Mg?Al LDO in adsorbing and removing fluoride ions. The results showed that the Zn?Mg?Al LDO prepared under the conditions of n（Zn2+）/n（Mg2+）/n（Al3+）=2∶1∶1, reaction temperature of 75 ℃, and calcination temperature of 400 ℃ exhibited the best adsorption and removal performance of fluoride ions, with an adsorption and removal rate of 85.39%. Zn?Mg?Al LDO has characteristic peaks of hydrotalcite, good crystal structure, and a layered structure. Zn?Mg?Al LDO is a mesoporous material with a specific surface area of 103.15 m2/g. In addition, the kinetics and adsorption mechanism of the adsorption process were also studied. The results indicate that the adsorption process follows the Langmuir adsorption isotherm and quasi second?order kinetic equation.
