A cascade of in situ conversion of bicarbonate to CO_(2) and CO_(2) electroreduction in a flow cell with a Ni-N-S catalyst

Combination of CO_(2) capture using inorganic alkali with subsequently electrochemical conversion of the resultant HCO_(3)^(-)to high-value chemicals is a promising route of low cost and high efficiency.The electrochemical reduction of HCO_(3)^(-)is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface.Herein,we adopt a comprehensive strategy to tackle this challenge,i.e.,cascade of in situ chemical conversion of HCO_(3)^(-)to CO_(2) and CO_(2) electrochemical reduction in a flow cell.With a tailored Ni-N-S single atom catalyst(SACs),where sulfur(S)atoms located in the second shell of Ni center,the CO_(2)electroreduction(CO_(2)ER)to CO is boosted.The experimental results and density functional theory(DFT)calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom,thereby stabilizing^(*)H over N and boosting the first proton coupled electron transfer process of CO_(2)ER,i.e.,^(*)+e^(-)+^(*)H+^(*)CO_(2)→^(*)COOH.As a result,the obtained catalyst exhibits a high faradaic efficiency(FE_(CO)~98%)and a low overpotential of 425 mV for CO production as well as a superior turnover frequency(TOF)of 47397 h^(-1),outcompeting most of the reported Ni SACs.More importantly,an extremely high FECOof 90%is achieved at 50 mA cm^(-2)in the designed membrane electrode assembly(MEA)cascade electrolyzer fed with liquid bicarbonate.This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO_(2)ER,but also provides an alternative and feasible strategy to realize the electrochemical conversion of HCO_(3)^(-)to high-value chemicals.

改性Zn-MOF-74对硫化氢的吸附研究

MOF-74具有独特的金属五配位四方锥构型,在气体吸附领域具有广泛的应用前景。采用理论计算和实验相结合的方法研究了改性前后Zn-MOF-74对硫化氢(H_(2)S)的吸附。利用巨正则蒙特卡罗(GCMC)模拟和密度泛函理论(DFT)计算分析了Co和Ni金属中心改性的Zn-MOF-74对H_(2)S吸附位点的变化、与H_(2)S的相互作用以及吸附性能。结果表明:Zn-Co-MOF-74和Zn-Ni-MOF-74对H_(2)S的优先吸附位点仍在Zn原子处,并且孔腔内吸附的H_(2)S分子明显增多,O吸附位点吸附能力也有所提高。Zn-Co-MOF-74和Zn-Ni-MOF-74对H_(2)S的吸附容量明显提升,这与MOF对H_(2)S的稳定性增强有关,Zn-MOF-74与H_(2)S之间过强的相互作用会导致MOF结构坍塌,阻碍H_(2)S扩散,进而影响其吸附性能。

Measurement and Correlation for Solubility of （S）-（＋）-2,2-Dimethylcyclopropane Carbox Amide in Different Solvents

（S）-（＋）-2,2-dimethylcyclopropane carbox amide is a key intermediate of Cilastatin, an inhibitor of dehydropeptidase-I. Its corresponding solid-liquid equilibrium data will provide essential support for industrial design and further theoretical studies. The solubilities of （S）-（＋）-2,2-dimethylcyclopropane carbox amide in toluene, dichloromethane, trichloromethane, ethyl acetate, ethanol and pure water at different temperature were measured using the synthetic method by a laser monitoring observation technique. The solubility data were correlated with the modified Apelblat equation.The calculated values were good in agreement with the experimental values.

Measurement and Correlation for Solubility of (S)-(+)-2,2-Dimethyl-cyclopropane Carbox Amide in Different Solvents

(S)-(+)-2,2-dimethylcyclopropane carbox amide is a key intermediate of Cilastatin, an inhibitor of de- hydropeptidase-I. Its corresponding solid-liquid equilibrium data will provide essential support for industrial design and further theoretical studies. The solubilities of (S)-(+)-2,2-dimethylcyclopropane carbox amide in toluene, di- chloromethane, trichloromethane, ethyl acetate, ethanol and pure water at different temperature were measured us- ing the synthetic method by a laser monitoring observation technique. The solubility data were correlated with the modified Apelblat equation. The calculated values were good in agreement with the experimental values.

Effect of carbon dioxide on oxy-fuel combustion of hydrogen sulfide:An experimental and kinetic modeling

CO_(2) is an important component in the acid gas and it is necessary to study the effect of CO_(2) presence on the oxy-fuel combustion of H_(2)S with particular focus on the formation of carbonyl sulfide(COS).The oxyfuel combustion of acid gas was conducted in a coaxial jet double channel burner.The distribution of flame temperature and products under stoichiometric condition along axial(R=0.0)and radial at about 3.0 mm(R=0.75)were analyzed,respectively.The Chemkin-Pro software was used to analyze the rate of production(ROP)for gas products and the reaction pathway of acid gas combustion.Both experimental and simulation results showed that acid gas combustion experienced the H2S chemical decomposition,H_(2)S oxidation and accompanied by H_(2) oxidation.The CO_(2) presence reduced the peak flame temperature and triggered the formation of COS in the flame area.COS formation at R=0.0 was mainly through the reaction of CO_(2) and CO with sulfur species,whereas at R=0.75 it was through the reaction of CO with sulfur species.The ROP results indicated that H_(2) was mainly from H_(2)O decomposition in the H_(2)S oxidation stage,and COS was formed by the reaction of CO_(2) with H_(2)S.ROP and other detailed analysis further revealed the role of H,OH and SH radicals in each stage of H_(2)S conversion.This study revealed the COS formation mechanisms with CO_(2) presence in the oxy-fuel combustion of H_(2)S and could offer important insights for pollutant control.

Insight into the effect of gel drying temperature on the structure and desulfurization performance of ZnO/SiO_(2)adsorbents

A series of ZnO/SiO_(2) adsorbents were prepared by a sol-gel method using tetraethyl orthosilicate,ethylene glycol(EG)and nitrates as precursors.The effect of gel drying temperature on the structure and desulfurization performance of the adsorbents were investigated in detail.It is found that the low drying temperature led to a weak interaction among EG,Si AOH/H_(2)O and the nitrates in the gel system,which caused the oxidation of EG by NO3-and formed zinc glyoxylate complex during the gel calcination process,whereas this oxidation process also occurred at a high drying temperature during the gel drying process.The formed zinc glyoxylate complex promoted the generation of monodentate carbonate on the surface of Zn O,which resulted in the inferior desulfurization performance of adsorbents despite they have smaller Zn O nanoparticles.The gel dried at 120°C formed the hydrogen bonds between EG and Si AOH/H_(2)O and a strong interaction between zinc oxo-clusters and NO3-was also found in the gel system,which avoided the oxidation of EG by NO3-during the preparation process and the Zn O nanoparticles with sizes of 6 nm were formed by a combustion method.The adsorbent affords a highest sulfur capacity of 104.9 mg·g^(-1) in this case.In addition,the gel drying temperature has a significant influence on the textural properties of the adsorbents except their surface area.

Regulation of excitation energy transfer in Sb-alloyed Cs_(4)MnBi_(2)Cl_(12) perovskites for efficient CO_(2) photoreduction to CO and water oxidation toward H_(2)O_(2)

Lead(Pb)-free halide perovskites have recently attracted increasing attention as potential catalysts for CO_(2) photoreduction to CO due to their potential to capture solar energy and drive catalytic reaction.However,issues of the poor charge transfer still remain one of the main obstacles limiting their performance due to the overwhelming radiative and nonradiative charge-carrier recombination losses.Herein,Pb-free Sb-alloyed all-inorganic quadruple perovskite Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12)(0≤x≤1)is synthesized as efficient photocatalyst.By Sb alloying,the undesired relaxation of photogenerated electrons from conduction band to emission centers of[MnCl6]^(4-)is greatly suppressed,resulting in a weakened PL emission and enhanced charge transfer for photocatalyst.The ensuing Cs_(4)Mn(Bi_(1-x)Sb_(x))_(2)Cl_(12) photocatalyst accomplishes efficient conversion of CO_(2)into CO,accompanied by a surprising production of H_(2)O_(2),a high valueadded product associated with water oxidation.By optimizing Sb^(3+) concentration,a high CO evolution rate of 35.1μmol g^(-1)h^(-1)is achieved,superior to most other Pb and Pb-free halide perovskites.Our findings provide new insights into the mixed-cation alloying strategies for improved photocatalytic performance of Pb-free perovskites and shed light on the rational design of robust band structure toward efficient energy transfer.

Solubility of CO_(2) in nonaqueous system of 2-(butylamino)ethanol with 2-butoxyethanol:Experimental data and model representation

Nonaqueous amine-based system is an attractive solution to overcome high-energy-intensive CO_(2) capture process using the conventional aqueous amines.Advanced nonaqueous absorbent of 2-(butylamino)ethanol(BAE)with 2-butoxyethanol(2-BE)has been recently proposed for low-energyconsumption CO_(2) capture.In this work,Henry’s law constants of CO_(2) in the BAE/2-BE blend were obtained by N_(2)O/CO_(2) analogy,and correlated in the temperature range of(283–333)K.Vapor-liquid equilibrium(VLE)data for the BAE+CO_(2)+2-BE system at 65.4%(mass)BAE were also determined in a stirred equilibrium cell at temperatures of(313–393)K and CO_(2) partial pressures up to 275 kPa.A single apparent equilibrium constant KCO_(2);app was proposed for this system and correlated as a function of temperature,carbonated degree of amine and CO_(2) loading.Solubility data were well represented by the modified Kent-Eisenberg model with an average absolute relative deviation(AARD)of 13%.

Synergetic enhancement of selectivity for electroreduction of CO_(2)to C_(2)H_(4)by crystal facet engineering and tandem catalysis over silver-incorporated-cuprous oxides

Electrochemical CO_(2)reduction to C_(2)H_(4)can provide a sustainable route to reduce globally accelerating CO_(2)emissions and produce energy-rich chemical feedstocks.However,the poor selectivity in C_(2)H_(4)electrosynthesis limits its implementation in industrially interesting processes.Herein,we report a composite structured catalyst composed of Ag and Cu_(2)O with different crystal faces to achieve highly efficient reduction of CO_(2)to C_(2)H_(4).The catalyst composed of Ag and octahedral Cu_(2)O enclosed with(111)facet exhibits the best CO_(2)electroreduction performance,with the Faradaic efficiency(FE)and partial current density reaching 66.8%and 17.8 mA cm2 for C_(2)H_(4)product at-1.2 VRHE in 0.5 M KHCO_(3),respectively.Physical characterization and electrochemical test analysis indicate that the high selectivity for C_(2)H_(4)product stems from the synergistic effect of crystal faces control engineering and tandem catalysis.Specifically,Ag can provide optimal availability of CO intermediate by suppressing hydrogen evolution;subsequently,C-C coupling is promoted on the intimate surface of Cu_(2)O with facetdependent selectivity.The insights gained from this work may be beneficial for designing efficient multicomponent catalysts for improving the selectivity of electrochemical CO_(2)reduction reaction to generate C2þproducts.

Simultaneous Removal of COS and H_2S at Low Temperatures over Nanoparticle a-FeOOH Based Catalysts

Catalysts using α-FeOOH nanoparticles as the active ingredient were testedby a microreactor-chromatography assessing apparatus at atmospheric pressure between 25 and 60 ℃with a gas hourly space velocity of 10,000 h^(-1), while the removal performance of H_2S withcatalysts was investigated using the thermal gravimetric method. The results show that the catalystsare highly active for COS hydrolysis at low temperatures (≤60 ℃) and high gas hourly spacevelocity, and the highest activity can reach 100%. The catalyst is particularly stable for 12 h, andno deactivation is observed. Nanoparticle α-FeOOH prepared using hydrated iron sulfate showshigher COS hydrolysis activity, and the optimum calcination temperature for the catalyst is 260 ℃.In addition, the catalysts can remove COS and H_2S simultaneously, and 60 ℃ is favorable for theremoval of H_2S. The compensation effect exists in nanoparticle-based catalysts.

Eliminating H_(2)O/HF and regulating interphase with bifunctional tolylene-2,4-diisocyanate(TDI)additive for long life Li-ion battery

Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development.

Self-assembled S-scheme In_(2.77)S_(4)/K^(+)-doped g-C_(3)N_(4)photocatalyst with selective O_(2)reduction pathway for efficient H_(2)O_(2)production using water and air

The development of an efficient artificial H_(2)O_(2)photosynthesis system is a challenging work using H_(2)O and O_(2)as starting materials.Herein,3D In2.77S_(4)nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In2.77S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2)production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In2.77S_(4),respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In2.77S_(4)according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2)production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2)around the active centers,the energy barriers of O_(2)protonation and H_(2)O_(2)desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2)photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.

A critical review towards the causes of the iron-based catalysts deactivation mechanisms in the selective oxidation of hydrogen sulfide to elemental sulfur from biogas

Hydrogen sulfide(H_(2)S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment,even at low concentrations.Among various technologies,the selective oxidation of hydrogen sulfide(SOH_(2)S) to elemental sulfur(S) has emerged as a sustainable and environmentally friendly solution.Due to its unique properties,iron oxide has been extensively investigated as a catalyst for SOH_(2)S;however,rapid deactivation has remained a significant drawback.The causes of iron oxide-based catalysts deactivation mechanisms in SOH_(2)S,including sulfur or sulfate deposition,the transformation of iron species,sintering and excessive oxygen vacancy formation,and active site loss,are thoroughly examined in this review.By focusing on the deactivation mechanisms,this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH_(2)S.

Molten salt construction of core-shell structured S-scheme CuInS_(2)@CoS_(2)heterojunction to boost charge transfer for efficient photocatalytic CO_(2)reduction

Weak redox ability and severe charge recombination pose significant obstacles to the advancement of CO_(2)photoreduction.To tackle this challenge and enhance the CO_(2)photoconversion efficiency,fabricating well-matched S-scheme heterostructure and establishing a robust built-in electric field emerge as pivotal strategies.In pursuit of this goal,a core-shell structured CuInS_(2)@CoS_(2)S-scheme heterojunction was meticulously engineered through a two-step molten salt method.This approach over the CuInS_(2)-based composites produced an internal electric field owing to the disparity be-tween the Fermi levels of CoS_(2)and CuInS_(2)at their interface.Consequently,the electric field facili-tated the directed migration of charges and the proficient separation of photoinduced carriers.The resulting CuInS_(2)@CoS_(2)heterostructure exhibited remarkable CO_(2)photoreduction performance,which was 21.7 and 26.5 times that of pure CuInS_(2)and CoS_(2),respectively.The S-scheme heterojunc-tion photogenerated charge transfer mechanism was validated through a series of rigorous anal-yses,including in situ irradiation X-ray photoelectron spectroscopy,work function calculations,and differential charge density examinations.Furthermore,in situ infrared spectroscopy and density functional theory calculations corroborated the fact that the CuInS_(2)@CoS_(2)heterojunction substan-tially lowered the formation energy of*COOH and*CO.This study demonstrates the application potential of S-scheme heterojunctions fabricated via the molten salt method in the realm of ad-dressing carbon-related environmental issues.

A thorough analysis of the effect of surfactant/s on the solubility and pharmacokinetics of (S)-zaltoprofen

Until now, there are no publications about the preformulation studies on(S)-zaltoprofen((S)-ZPF). Hence, we first investigated the solubility of(S)-ZPF, screened solubilizers and performed the pharmacokinetic study of(S)-ZPF in the presence of the solubilizers. The measurement of the solubility of(S)-ZPF in 26 different solvents was carried out, including d-alpha tocopheryl polyethylene glycol 1000 succinate(TPGS), 2-hydroxypropyl-β-cyclodextrin(HPCD), and mixtures of individual solvent. The plasma concentration of(S)-ZPF and the amount of(S)-ZPF retained in stomach were determined after oral(35.0 mg/kg) and intravenous(5.0 mg/kg) administration. The solubility of(S)-ZPF showed an increase of 484-fold in TPGS compared to its aqueous solubility. There was a significant increase of AUC 0-24 h for pure(S)-ZPF in the TPGS group(813.59 ± 64.17 μg h/ml) in comparison with AUC 0-24 h in the HPCD group(595.57 ± 71.76 μg h/ml) and water group(465.57 ± 90.89 μg h/ml). In addition, the T max of(S)-ZPF in the TPGS group was 2 h, much faster than that in the HPCD or water groups(5.50 or 5.67 h, respectively). This suggested that TPGS played a significant role in the increase of solubility and bioavailability of(S)-ZPF.

Integration of a fused silica capillary and in-situ Raman spectroscopy for investigating CO_(2) solubility in n-dodecane at near-critical and supercritical conditions of CO_(2)

To determine the solubility of CO_(2)in n-dodecane at T=303.15-353.15 K,P≤11.00 MPa,an integrated fused silica capillary and in-situ Raman spectroscopy system was built.The Raman peak intensity ratio(I_(CO_(2))/IC-H)between the upper band of CO_(2)Fermi diad(I_(CO_(2)))and the C-H stretching band of n-dodecane(IC-H)was employed to determine the solubility of CO_(2)in n-dodecane based on the calibrated correlation equation between the known CO_(2)molality in n-dodecane and the I_(CO_(2))/IC-Hratio with R^(2)=0.9998.The results indicated that the solubility of CO_(2)decreased with increasing temperature and increased with increasing pressure.The maximum CO_(2)molality(30.7314 mol/kg)was obtained at 303.15 K and7.00 MPa.Finally,a solubility prediction model(lnS=(P-A)/B)based on the relationship with temperature(T in K)and pressure(P in MPa)was developed,where S is CO_(2)molality,A=-8×10^(-6)T^(2)+0.0354T-8.1605,and B=0.0405T-10.756.The results indicated that the solubilities of CO_(2)derived from this model were in good agreement with the experimental data.

Investigating the charge transfer mechanism of ZnSe QD/COF S-scheme photocatalyst for H_(2)O_(2)production by using femtosecond transient absorption spectroscopy

Hydrogen peroxide(H_(2)O_(2))has gained widespread attention as a versatile oxidant and a mild disin-fectant.Here,an electrostatic self-assembly method is applied to couple ZnSe quantum dots(QDs)with a flower-like covalent organic framework(COF)to form a step-scheme(S-scheme)photocata-lyst for H_(2)O_(2)production.The as-prepared S-scheme photocatalyst exhibits a broad light absorption range with an edge at 810 nm owing to the synergistic effect between the ZnSe QDs and COF.The S-scheme charge-carrier transfer mechanism is validated by performing Fermi level calculations and in-situ X-ray photoelectron and femtosecond transient absorption spectroscopies.Photolumi-nescence,time-resolved photoluminescence,photocurrent response,electrochemical impedance spectroscopy,and electron paramagnetic resonance results show that the S-scheme heterojunction not only promotes charge carrier separation but also boosts the redox ability,resulting in enhanced photocatalytic performance.Remarkably,a 10%-ZnSe QD/COF has excellent photocatalytic H_(2)O_(2)-production activity,and the optimal S-scheme composite with ethanol as the hole scavenger yields a H_(2)O_(2)-production rate of 1895 mol g^(-1)h-1.This study presents an example of a high-performance organic/inorganic S-scheme photocatalyst for H_(2)O_(2)production.

水泥石防CO_2、H_2S腐蚀性能的室内研究

通过分析CO_2、H_2S对水泥石的腐蚀机理,采用一种新型的通过聚合反应生成的线性水溶性高分子乳状液防腐蚀剂,考察了在腐蚀条件下,净水泥浆、加入新型防腐蚀剂的水泥浆、加入填充材料的水泥浆以及加入防腐蚀剂和填充材料以后的水泥浆形成的水泥试块的抗压强度、渗透率和外貌形态变化,同时通过XL-30型扫描电子显微镜对水泥试块的内部结构进行了观察。实验表明,在水泥浆中同时加入新型防腐蚀剂和填充材料以后,水泥石的防腐蚀能力得到极大的提高,相对净浆来说,水泥石渗透率降低率达80.7%;由于防腐蚀剂具有一定的缓凝作用,所以水泥石抗压强度会受到一定的影响,若有需要,建议通过加大促凝剂量来调节其抗压强度值。

在含CO_2/H_2S介质中油气田用钢的腐蚀研究进展

研究了CO_2和H_2S对油气田开发用钢材的腐蚀机理、分析了影响因素以及防护措施,并对研究进展情况进行综述。指出目前国内各油气田关于CO_2/H_2S的腐蚀问题,一方面对腐蚀机理的认识还不够全面与深入,另一方面其防护技术研究尚未达到系统化和实用化的程度。

含CO_2-H_2S酸性气田冲刷腐蚀概述

天然气管线的安全服役对国民生产和生活意义重大。近年来,随着对含高浓度CO_2、H_2S等强腐蚀性介质酸性气田的大量开发,输送压力和流速不断提高,通过采用传统脱硫、脱CO_2、缓蚀剂等技术在实际应用中效果有限,导致天然气管线的腐蚀失效情况仍比较严重,尤其是三通、法兰、焊缝等特殊位置。本文通过阐述CO_2-H_2S酸性气田冲刷腐蚀的特征和影响因素,总结了含CO_2-H_2S酸性气田中冲刷腐蚀的研究进展,指出研究天然气高速冲刷与薄液电化学相互作用和腐蚀发生机理对预防天然气管线钢的冲刷腐蚀有较重要的意义。