加钛超低碳钢中Ti系碳硫化物的析出行为

用透射电子显微镜（ＴＥＭ）详细调查了加钛超低碳钢中Ｔｉ系碳硫化物的析出行为。在加热到１２５℃后于９５０℃保温的试样到Ｔｉｘ、ＭｎＳ的共析出在奥氏体晶界形成链状析出物。这好象是借助于硫的原始晶界而在界面产生的优析出。反之，在９５０℃热加工时，由于再强晶抑制了ＴｉＳ、ＭｎＳ在奥氏体晶界的共析出，促进了奥氏体晶粒内Ｔｉ４Ｃ２Ｓ２的应变感生无效新出。在加热到１２５０℃后于９５０℃曙的情况下。

微波焙烧处理含碳硫化物金精矿的研究

同时含有碳和硫（硫矿物包裹金）的金矿石称为双重难处理矿石。从该类矿石中提取金一般需要采用氧化预处理方法，即使微细粒金从硫化物基质中解离，脱除具有“劫金”效应的碳质物。对采用微波焙烧技术处理双重难处理浮选金精矿，氧化脱除精矿中硫化物和碳质物进行了研究。利用热重和红外光谱分析对精矿进行了表征，通过测定介电常数考察了精矿对微波的吸收性能。

超低碳钢钛的硫化物和碳硫化物的溶度积

定量研究了钛稳定化无间隙原子钢的平衡析出行为。通过溶解试验测定了ＴｉＳ和Ｔｉ４ Ｃ２Ｓ２的溶度积。结果如下：Ｌｏｇ〖Ｔｉ〗〖ｓ〗＝－１３９７５／Ｔ＋５．４３；ｌｏｇ〖Ｔｉ〗〖Ｃ〗＾０．５〖Ｓ〗＾０．５＝－１７０４５／Ｔ＋７．９用溶度积公式计算的结果与不包括溶解试验在内的其它试验结果相吻全。将本研究所得到的沉吟度积试验结果与不同试验所得到的ＴｉＳ、Ｔｉ４Ｃ２Ｓ２溶度积结果相比较说明。

一锅法合成多金属硫化物/碳复合材料及其储锂性能

多金属硫化物/碳(MMS/C)复合材料因其良好的结构稳定性、充足的活性位点和有益的协同效应,在能源、催化、传感、环境科学等领域具有良好的应用潜力。然而,MMS/C复合材料繁琐、低效和对环境有害的制备方法制约了其发展。本文报道了一种简易、通用的制备策略合成了系列MMS/C复合材料。该策略的关键是采用了碳源-非碳前驱体一体化的离子交换树脂-金属离子杂化组装体作为构筑单元,可实现均匀的多相有机/无机界面,在高温条件下原位生成封装于碳骨架中的金属硫化物。通过改变金属离子的种类,实现了14种MMS/C复合材料的合成。基于其组分和结构优势,所制MMS/C复合材料表现出高效、快速和持久的锂离子存储性能。其中,ZnS-Co_(9)S_(8)/C复合材料在0.1 A·g^(-1)电流密度下循环600次后仍具有651 mAh·g^(-1)的可逆储锂容量;当电流密度提高20倍时,容量保持率超过54%,展现出优异的倍率性能。本文提出的均一、多相有机/无机界面合成策略有望扩展用于制备其他金属化合物(如金属磷化物、金属硒化物等)/碳复合材料,为多金属化合物/碳复合材料的合成提供有效的途径。

含碳多金属硫化物型金矿选厂工艺改造实践

某含碳多金属硫化物型金矿选厂采用混合浮选+混合精矿脱药再磨氰化(氰化贵液高温高压解吸电积工艺)+氰渣浮选锌工艺,存在高碳混合精矿氰化回收率过低、锌硫分离困难、载金碳无法顺利解吸循环利用等问题,试运行期间金综合回收率不足70%。改为混合精矿抑硫浮铜铅锌精矿+硫精矿氰化流程,优化混合浮选药剂制度和分离浮选流程后,通过闭路试验和氰化试验验证金综合回收率高达89.50%,实际生产金综合回收率89.35%以上。本次改造实践经验可供同类型金矿选矿厂参考。

高循环性能的FeCo_(2)S_(4)/碳纤维复合电极材料

对电极材料的结构进行优化设计,提高电活性材料的有效利用率。提出一种简单的一步电沉积双金属硫化物的策略,成功设计并制备了FeCo_(2)S_(4)双金属硫化物,沉积在高导电性、高比表面积碳纤维布上的复合材料,并应用于超级电容器作为电极材料。通过电沉积法获得的FeCo_(2)S_(4)/CFC(FeCo_(2)S_(4)/碳纤维布)复合材料不仅改善了机械稳定性,并且进一步提升了复合材料的倍率性能和储能能力。研究结果表明:FeCo_(2)S_(4)/CFC具有出色的电化学性能,在1 A/g时具有505.33 F/g的高比电容,并且具有良好的倍率性能(10 A/g时比电容仍达到324 F/g)。出色的倍率性能归因于碳纤维布的加入,提高了复合材料的导电性。同时,对FeCo_(2)S_(4)/CFC材料进行10000次循环后,仍然可保持95.25%的循环稳定性。

富燃料条件下CH_(4)对H_(2)S氧化及COS和CS_(2)生成的影响

研究了H_(2)S/CH_(4)的富燃料燃烧过程,考察了三种燃气比例(H_(2)S与CH_(4)体积比为4:1,1:1,1:4)下,CH_(4)对H_(2)S氧化及COS和CS_(2)生成过程的影响。实验过程中,采用同轴双通道烧嘴,H_(2)S与CH_(4)经烧嘴中心通道进入射流反应器,空气经烧嘴环隙通道进入反应器,形成扩散火焰,测定了稳定后反应器中心轴向各位置的温度和气体浓度。结果表明:靠近烧嘴区域,H_(2)S在与CH_(4)的竞争氧化中处于优势,产物主要有S_(2)和H_(2)O,CO与CO_(2)的生成受到抑制;生成的S_(2)能与未氧化的CH_(4)进行反应生成CS_(2),可以观察到CS_(2)浓度明显高于CO_(2),由此推断此时CH_(4)与S_(2)的反应速率可能快于其与O_(2)的反应速率。在温度峰值区域大量生成H_(2),CO和C_(2)H_(4),并在反应器中下游被氧化消耗,开始大量生成SO_(2)。此外,由于CO浓度低,难以与S_(2)和SH等含硫物质反应生成COS,因而COS浓度较低。

Sulfur phase and sulfur removal in high sulfur-containing bauxite

The sulfur phase in high sulfur-containing bauxite was studied by an X-ray diffraction analysis and a chemistry quantitative analysis.The methods for the removal of different shaped sulfur were also discussed.The results show that sulfur phases in high sulfur-containing bauxites exist in the main form of sulfide sulfur （pyrite） or sulfate sulfur,and the main sulfur forms of bauxites from different regions are not the same.Through a combination of an X-ray diffraction analysis and a chemistry quantitative analysis,the sulfur phases of high sulfur-containing bauxite could be accurately investigated.Deciding the main sulfur form of high sulfur-containing bauxite could provide theoretical instruction for choosing methods for the removal of sulfur from bauxite,and an oxidizing-roasting process is an effective way to remove sulfide sulfur from high sulfur-containing bauxite,the content of S^2-in crude ore in the digestion liquor is above 1.7 g/L,but in the roasted ore digestion liquor,it is below 0.18 g/L.Using the sodium carbonate solution washing technology to wash bauxite can effectively remove sulfate sulfur,the content of the total sulfur in ore is lowered to below 0.2% and can meet the production requirements for the sulfur content.

Interfacial engineering of graphitic carbon nitride(g-C_3N_4)-based metal sulfide heterojunction photocatalysts for energy conversion: A review

As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-C3N4) has become research hotspots in the community. However, g-C3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-C3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-C3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-C3N4,(2) modification strategies of g-C3N4,(3) design principles of TMS-modified g-C3N4 heterostructured photocatalysts, and (4) applications in energy conversion. What is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-C3N4-based heterostructured photocatalysts in H2 evolution, CO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-C3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.

Sulfur promoted n-π^(*)electron transitions in thiophene-doped g-C_(3)N_(4)for enhanced photocatalytic activity

Expanding the optical absorption range of photocatalysts is still a key endeavor in graphitic carbon nitride(g-C_(3)N_(4))studies.Here,we report on a novel thiophene group extending the optical property,which is assigned to n-π^(*)electronic transitions involving the two lone pairs on sulfur(TLPS).The as-prepared samples,denoted as CN-ThAx(where x indicates the amount of ThA added,mg),showed an additional absorption above 500 nm as compared to pristine g-C_(3)N_(4).Further,the thiophene group enhanced charge carrier separation to suppress e‒/h+pair recombination.The experimental results suggest that the thiophene group can obstruct the polymerization of melem to generate a large plane,thus exposing the lone electron pairs on the sulfur.The photocatalytic activity was evaluated in the decomposition of bisphenol A and H2 evolution.Compared with g-C_(3)N_(4),the optimized CN-ThA_(30) sample led to a 6.6-and 2-fold enhancement of the degradation and H2 generation rates,respectively.The CN-ThA_(30) sample allowed for synchronous H2 production and BPA decomposition.

Strategies to improve electrocatalytic and photocatalytic performance of two-dimensional materials for hydrogen evolution reaction

Two-dimensional materials(2D)with unique physicochemical properties have been widely studied for their use in many applications,including as hydrogen evolution catalysts to improve the efficiency of water splitting.Recently,typical 2D materials MoS2,graphene,MXenes,and black phosphorus have been widely investigated for their application in the hydrogen evolution reaction(HER).In this review,we summarize three efficient strategies—defect engineering,heterostructure formation,and heteroatom doping—for improving the HER performance of 2D catalysts.The d-band theory,density of states,and Fermi energy level are discussed to provide guidance for the design and construction of novel 2D materials.The challenges and prospects of 2D materials in the HER are also considered.

Synergy of adsorption and visible light photocatalysis to decolor methyl orange by activated carbon/nanosized CdS/chitosan composite

Activated carbon/nanosized CdS/chitosan(AC/n-CdS/CS) composites as adsorbent and photoactive catalyst were prepared under low temperature(≤60 ℃) and ambient pressure.Methyl orange(MO) was chosen as a model pollutant to evaluate synergistic effect of adsorption and photocatalytic decolorization by this innovative photocatalyst under visible light irradiation.Effects of various parameters such as catalyst amount,initial MO concentration,solution pH and reuse of catalyst on the decolorization of MO were investigated to optimize operational conditions.The decolorization of MO catalyzed by AC/n-CdS/CS fits the Langmuir-Hinshelwood kinetics model,and a surface reaction,where the dyes are absorbed,is the controlling step of the process.Decolorization efficiency of MO is improved with the increase in catalyst amount within a certain range.The photodecolorization of MO is more efficient in acidic media than alkaline media.The decolorization efficiency of MO is still higher than 84% after five cycles and 60 min under visible light irradiation,which confirms the reusability of AC/n-CdS/CS composite catalyst.

Enhanced Performance of Denitrifying Sulfide Removal Process by 1,2-Naphthoquinone-4-Sulphonate

The denitrifying sulfide removal(DSR) process with bio-granules comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide and acetate species into di-nitrogen gas, elemental sulfur and carbon dioxide, respectively, at high loading rates. This study has determined that the reaction rate of sulfide oxidized into sulfur could be enhanced in the presence of 1,2-naphthoquinone-4-sulphonate(NQS). The presence of NQS mitigated the inhibition effects of sulfide species on denitrification. Furthermore, the reaction rates of nitrate and acetate to nitrogen gas and CO_2, respectively, were also promoted in the presence of NQS, thereby enhancing the performance of DSR granules. The advantages and disadvantages of applying the NQS-DSR process are discussed.

Study on durability of concrete in coal mine

There are sulfate and chloride ions corrosion and carbonation to concrete in coal mine. Based on taking test of accelerated carbonation, corrosion of 3.5% weight of NaCl solution and 5% weight of Na2SO4 solution of coal mine concretes, durability of con- cretes which include spray concrete of C20,high performance concretes of C30 and C50 and effect of fly ash on durability have been studied. Results suggest that the coal mineral high performance concretes show good resistance capacities of carbonation, sulfate and chloride corrosion to meet the coal mine construction. And the higher the strength grade is, the better the resistance capacity of corrosion of carbonation is, chloride and sulfate. Moreover, fly ash improves resistance capacity of high performance concrete(HPC) to chloride and sulfate but decreases the resistance capacity of C30’s to carbonation and average dynamic modulus.

Atomic modulation of Fe‐Co pentlandite coupled with nitrogen‐doped carbon sphere for boosting oxygen catalysis

Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like hollow carbon sphere is well designed on octahedral and tetrahedral sites.The robust FexCo9−xS8‐NHCS‐V with iron replacing at the octahedron possesses prolonged metal sulfur bond and exhibits excellent bifunctional electrocatalytic performance towards oxygen reduction reaction(ORR,E_(1/2)=0.80 V vs.RHE)and excellent oxygen evolution reaction(OER,E_(j=10)=1.53 V vs.RHE)in 0.1 mol/L KOH.Accordingly,a rechargeable Zn‐air battery of Fe_(x)Co_(9−x)S_(8)‐NHCS‐V cathode endows high energy efficiency(102 mW cm^(−2)),and a microbial fuel cell achieves a high‐power density(791±42 mW m^(−2)),outperforming the benchmark Pt/C catalyst.

Catalytic oxidation of CS_2 over atmospheric particles and oxide catalysts

The catalytic oxidization of CS2 over atmospheric particles and some oxide catalysts was explored through FT-IR, MS and a fixed-bed stainless steel reactor. The results show that atmospheric particles and some oxide catalysts exhibited considerable oxidizing activities for CS2 at ambient temperature. The reaction products are mainly COS and elemental sulfur, even CO2 on some catalysts. Among the catalysts, CaO has the strongest catalytic activity for oxidizing CS2. Fe2O3 is weaker than CaO. The catalytic activity for Al2O3 reduces considerably compared with the former two catalysts, and SiO2 the weakest. Atmospheric particle samples’ catalytic activity is between Fe2O3’s and Al2O3’s. The atmospheric particle sample collected mainly consists of Ca(Al2Si2O8) · 4H2O, which is also the main component of cement. COS, the main product, is formed by the catalytic oxidization of CS2 with adsorbed “molecular” oxygen over the catalysts’ surfaces. The concentration of adsorbed oxygen over catalysts’ surfaces may be the key factor contributed to the oxidizing activity. It is indicated that CS2 could be catalytically oxidized over atmospheric particles, which induced that this reaction may be another important source of atmospheric COS from CS2.

S, N co-doped carbon nanotube-encapsulated core-shelled CoS2@Co nanoparticles： efficient and stable bifunctional catalysts for overall water splitting

Hydrogen, serving as a clean, sustainable energy source, may be mainly produced from electrolysis water. Herein, we report cobalt disulphide encapsulated in self-catalyzed carbon nanotubes （S, N-CNTs/ CoS2@Co） serving as a bifunctional catalyst, which exhibits excellent hydrogen evolution reaction perfor-mance （10.0 mAcm^-2 at 0.112 V, and low Tafel slope for 104.9 mV dec^-1 ） and oxygen evolution reaction performance （10.0 mAcm^-2 at 1.57 V, and low Tafel slope for 76.1 mV dec^-1）, meanwbile with a strong stability at various current densities. In-depth study reveals that the excellent catalytic properties can be mainly attributed to the increased catalytic sites induced by S, N co-doping, the improved electronic con-ductivity derived from the carbon nanotubes, and Mott-Schottky effect between the metal cobalt and semiconductive cobalt disulfide. Notably, when the bifunctional catalysts are applied to overall water splitting, a low potential of 1.633 V at the current density of 10.0 mAcm^-2 is achieved, which can com-pete with the precious metal catalyst benchmarks in alkaline media, demonstrating its promising prac-ticability in the realistic water splitting application. This work elucidates a practicable way to the design of transition metal and nano-carbon composite catalysts for a broad application in the fields of energy chemistry.

Engineering two-dimensional metal oxides and chalcogenides for enhanced electro-and photocatalysis

Two-dimensional(2D)metal oxides and chalcogenides(MOs&MCs)have been regarded as a new class of promising electro-and photocatalysts for many important chemical reactions such as hydrogen evolution reaction,CO_(2) reduction reaction and N2 reduction reaction in virtue of their outstanding physicochemical properties.However,pristine 2D MOs&MCs generally show the relatively poor catalytic performances due to the low electrical conductivity,few active sites and fast charge recombination.Therefore,considerable efforts have been devoted to engineering 2D MOs&MCs by rational structural design and chemical modification to further improve the catalytic activities.Herein,we comprehensively review the recent advances for engineering technologies of 2D MOs&MCs,which are mainly focused on the intercalation,doping,defects creation,facet design and compositing with functional materials.Meanwhile,the relationship between morphological,physicochemical,electronic,and optical properties of 2D MOs&MCs and their electro-and photocatalytic performances is also systematically discussed.Finally,we further give the prospect and challenge of the field and possible future research directions,aiming to inspire more research for achieving high-performance 2D MOs&MCs catalysts in energy storage and conversion fields.

Recyclable cobalt-molybdenum bimetallic carbide modified separator boosts the polysulfide adsorption-catalysis of lithium sulfur battery

The polysulfide shuttling and sluggish redox kinetics,due to the notorious adsorption-catalysis underperformance,are the ultimate obstacles of the practical application of lithium-sulfur(Li-S)batteries.Conventional carbon-based and transition metal compound-based material solutions generally suffer from poor catalysis and adsorption,respectively,despite the performance gain in terms of the other.Herein,we have enhanced polysulfide adsorptioncatalytic capability and protected the Li anode using a complementary bimetallic carbide electrocatalyst,Co3 Mo3 C,modified commercial separator.With this demonstration,the potentials of bimetal compounds,which have been well recognized in other environmental catalysis,are also extended to Li-S batteries.Coupled with this modified separator,a simple cathode(S/Super P composite)can deliver high sulfur utilization,high rate performance,and excellent cycle stability with a low capacity decay rate of^0.034%per cycle at 1 C up to1000 cycles.Even at a high S-loading of 8.0 mg cm^-2 with electrolyte/sulfur ratio=6 m L g^-1,the cathode still exhibits high areal capacity of^6.8 m A h cm^-2.The experimental analysis and the first-principles calculations proved that the bimetallic carbide Co3 Mo3 C provides more binding sites for adsorbing polysulfides and catalyzing the multiphase conversion of sulfur/polysulfide/sulfide than monometallic carbide Mo2 C.Moreover,the modified separator can be reutilized with comparable electrochemical performance.We also showed other bimetallic carbides with similar catalytic effects on Li-S batteries and this material family has great promise indifferent energy electrocatalytic systems.