查找使用阿拉丁产品的科研文献

Ultrafast synthesis of near-zero-cost S-doped Ni(OH)2 on C3N5 under ambient conditions with enhanced photocatalytic activity

Lixiao Han,Cong Peng,Jinming Huang,Shengyao Wang,Xiaohu Zhang,Hao Chen,Yi Yang

Planting highly efficient and low-cost Ni-based noble-metal-free active sites on semiconductors is of great significance in the field of photocatalysis. Herein, taking wide visible-light-responsive 2D C3N5 as a model semiconductor, an impressive near-zero-cost 2D S-doped nickel hydroxide (S–Ni(OH)2) is grown on C3N5 ultrafast within 30 min under ambient conditions by facile reaction between extremely low-cost Ni(NO3)2 and Na2S in aqueous solution. The fabricated 2D S–Ni(OH)2–C3N5 hybrid exhibits enhanced photocatalytic performance for both H2 production from water and NO removal for air purification. The H2 production rate on S–Ni(OH)2–C3N5 is ∼7 times higher than that of Ni(OH)2–C3N5 and even slightly higher than that of Pt–C3N5, demonstrating its potential as a candidate for noble metal catalysts like Pt. In particular, an apparent quantum yield (AQY) value of 30.9% at 420 nm for H2 production is reached on 1.0 wt% S–Ni(OH)2–C3N5 due to quick internal charge transfer efficiency. In addition, ∼42% of NO can be purified in a continuous flow reaction system. This work affords a cost-efficient strategy to steer the photocatalytic property of Ni-based catalysts.

Preparation of a novel supramolecular intumescent flame retardants containing P/N/S/Fe/Zn and its application in polylactic acid

Qinyong Liu,Xingyu Chen,Guiyang Zhu,Xiaoyu Gu,Hongfei Li,Sheng Zhang,Jun Sun,Xiaodong Jin

A novel integrative supramolecular intumescent flame retardant was fabricated by self-assembly of melamine, p -aminobenzene sulfonic acid and phytic acid and was abbreviated as MAP. After chelation with Fe 3+ or Zn 2+ , the resulted products (MAP-Fe and MAP-Zn) were melt-blended with polylactic acid (PLA) to enhance the flame retardancy of PLA. The fire performance was characterized by limiting oxygen index (LOI), UL-94 vertical burning and cone calorimeter tests. The results showed that control PLA was flammable with a low LOI of 20.4%, and it cannot satisfy any UL-94 grade for its severe ignited dripping, whilst the incorporation of 3% MAP-Zn increased the LOI to 29.2％, upgraded the UL-94 rating to V-0, and reduced the peak heat release rate by 18.7%. It was proposed that MAP-Zn mainly promoted the formation of more graphitic carbon in the char residues . In addition, the presence of 3% MAP-Zn slightly reduced the tensile strength of PLA from 64.9 MPa of the control PLA to 60.1 MPa, which met the requirements of most practical applications.

Assessing the in vitro digestion of Sesbania gum, a galactomannan from S. cannabina, and subsequent impact on the fecal microbiota

Mengyi Zhou,Yuheng Tao,Ting Wang,Rong Wang,Qiang Yong

Despite the application as additives to control functional properties of food, little is known about the behavior of Sesbania gum (SG) from Sesbania cannabina seeds, in the gastrointestinal tract. SG is a kind of natural and water-soluble galactomannan consisting of a β-1,4-D-mannan backbone with single α-1,6-galactopyranosyl side branching units every 2.4 residues, mass of which is over 10 6 Da. Using in vitro human digestion models, we elucidated the molecular weight changes of SG during the digestion and fermentation and the interactions between SG and gut microbiota. The results showed that the molecular weight of SG was not obviously changed during the simulated saliva, gastric and small intestinal digestion, but was rapidly decomposed and consumed by gut microbiota. As revealed by RNA‐seq transcriptome analyses, the CAZyme genes encoded by gut bacteria were significantly up-regulated, especially the families GH5 and 4, which target β-mannopyranoside and α-galactopyranoside, respectively. SG degradation led in turn, to changes in the short-chain fatty acid production and microbiota composition as determined by HPLC and 16S-seq, respectively. Our work is helpful to understand some features of SG subjected to the potential digestion and fermentation, and the results suggest SG has potential to be developed as a functional food ingredient for gut health.

A new aminobenzoate-substituted s-triazin-based Zr metal organic frameworks as efficient catalyst for biodiesel production from microalgal lipids

Jun Cheng,Lei Qian,Hao Guo,Yuxiang Mao,Yang Shao,Weijuan Yang

In order to solve problems that large molecules of microalgal lipids were difficult to access active sites in micropore structures of traditional metal organic frameworks (MOF), a novel two-dimensional nanosheet catalyst (aminobenzoate-substituted s-triazin-based Zr metal organic frameworks, Zr-TATAB) that exposed more active sites with stronger acidity was synthesized through replacement of trimesate linker in water/acid-resistant Zr-based MOF-808 with 4,4 ́,4 ́ ́- s -triazine-1,3,5-triyltri- p -aminobenzoate (H 3 TATAB) to promote catalytic conversion efficiency of microalgal lipids to biodiesel . The binding energy of Zr increased by 0.2 eV due to electronic shift caused by triazine ring and imine groups in H 3 TATAB ligand, which led to more exposed Zr 4+ active sites in Zr-TATAB catalyst. Due to increase of charge on crystal edges, dissociation of terminal hydroxyl groups was inhibited and Coulomb repulsion was increased. Therefore, Zr-TATAB catalyst possessed higher dispersion to avoid from pore blocking and catalytic deactivation, which enhanced recycling performance of catalyst. Compared with MOF-808, the total number of acid and base sites in Zr-TATAB catalyst increased from 6.0 mmol g −1 to 8.0 mmol g −1 , while strength of acid sites increased with an increased ammonia desorption temperature by 150 °C, which led to an increased catalytic conversion efficiency of microalgal lipids to biodiesel to 98.2%.

Enhanced sulfur redox kinetics and polysulfide regulations with petal-like nickel hydroxide nanosheets/rGO modified separators in Li-S batteries

Changfeng Zhao,Xiaoxia Yang,Guang Xia,Jinglei Liu,Wenqian Zhang,Jie Xue,Shifeng Hou,Cheng Hu

Li-S batteries have been regarded as one of the most prospective energy-storage systems because of its high-energy-density. To suppress the shuttling effect of dissolved lithium polysulfides, different mass ratios petal-like nickel hydroxide nanosheets (NHN) decorated reduced graphene oxide (rGO) materials are synthesized in this study using a one-step hydrothermal method and applied modified separators in Li-S batteries. With up to 73.5 wt% of sulfur content in the cathode, the optimized sample (the mass ratio of graphene oxide to nickel nitrate is 1:9) enables discharge capacities up to 1579 mAh g −1 at 0.2 C (the areal sulfur loading is 5 mg cm −2 ). The cell also exhibits a retention of 840 mAh g −1 in specific capacity after 200 cycles, exhibiting higher utilizations and better cycling stabilities for Li-S batteries. Electrochemical measurements and density functional theory (DFT) calculations prove that NHN plays a critical role in promoting the redox reaction kinetics of Li-S batteries, and the high conductivity of rGO enhances the electrochemical function of NHN. This study provides a low cost approach for the developments of modified separators in future practical Li-S batteries.

A solvent-governed surface state strategy for rational synthesis of N and S co-doped carbon dots with multicolour fluorescence

Ming Wen,Zhenxing Qin,Wenhai Wang,Junchao Cui,Rui Zhang,Qingmei Zhang,Kun Li,Jinhong Li,Wen Yang,Yi Zhou

General synthesis of yolk-shelled FexQy@Carbon (Q = S, Se, P) film for high performance anode of sodium-ion batteries

Xiaojun Wang,Haichang Li,Changmeng Xu,Hongran Sun,Cheng Fan,Wenming Song,Huifang Li,Jiangshan Gao,Zhiming Liu,Yan He

Sodium-ion batteries (SIBs) have attracted widespread attention because of the economic benefit of low-cost and abundance of sodium resources. Iron-based electrodes (sulfide, selenide and phosphide) that operate through conversion mechanism have shown huge potential for excellent sodium-ion storage. However, the problems related with serious volume expansion and lack of general synthesis methods of iron-based materials shorten the cycle life and hindered their application in SIBs. Herein, a general synthetic strategy of electrospinning process was developed to achieve the yolk-shelled Fe x Q y @C (Q = S, Se and P) film for binder-free anode of high-performance SIBs. Such method has more precursor materials to choose from and is highly scalable. More importantly, the designed electrodes have a unique yolk-shell structure and a three-dimensional conductive network. When applied as a binder-free anode of SIBs, all three samples exhibit outstanding sodium storage performance (FeS 2 @C-40: remaining 280 mAh g −1 after 400 cycles at 1 A g −1 , Fe 7 Se 8 @C-40: remaining 186.5 mAh g −1 after 200 cycles at 0.1 A g −1 and FeP 4 @C-40: remaining 205 mAh g −1 after 1000 cycles at 0.5 A g −1 ). Therefore, the scalability and universality of this general synthetic strategy can open up a new direction for the exploration of high-energy density and flexible electrode materials.

A self-supported S-doped Fe-based organic framework platform enhances electrocatalysis toward highly efficient oxygen evolution in alkaline media

Cong Ling,Xinyan Leng,Xiao-Jie Lu,Jing-Han Li,Zhengkun Yang,An-Wu Xu

The oxygen evolution reaction (OER) is a great crucial half-reaction in many energy conversion and storage techniques to alleviate the problems of the energy crisis and environmental pollution. However, the development of a low-cost and easy-to-prepare OER electrocatalyst with glorious performance and superior stability remains a huge challenge. Recently, metal–organic frameworks (MOFs) have attracted tremendous interest owing to their charming features including ultrafine porosity, rich active metal sites and tunable structures. However, most MOFs directly acting as electrocatalysts for the OER have intrinsic low electrical conductivity, poor electrochemical activities and short-term durability, hindering their practical application. Herein, we develop a facile and effective one-pot solvothermal method to rationally design a new S-doped Fe-based organic framework grown on nickel foam (NF), which prominently boosts the OER performance. Specifically, S0.05–Fe-BTB/NF exhibits remarkable OER activity with an ultralow overpotential of only 231 mV to afford 20 mA cm−2 current density without iR drop compensation in alkaline media, as well as a small Tafel slope of 41 mV dec−1, superior to that of the commercial RuO2 electrocatalyst. Particularly, it also demonstrates outstanding catalytic durability under an overpotential of 235 mV for 50 h. More significantly, the probable active species during the OER process are determined to be the electrochemically transformed metal oxyhydroxide.

Synergistic constraint and conversion of lithium polysulfide using a 3D hollow carbon interlayer in ultrahigh sulfur content Li-S batteries

Dongyuan Lei,Jinkui Li,Mingwu Xiang,Zirui Zhao,Shixun Yang,Zhe Hu,Mingwei Yuan,Junming Guo,Yi Xia,Wei Bai

Low sulfur content and inevitable polysulfide shuttle effect have always been the critical obstacle of the practical application of high-energy–density lithium sulfur batteries. Herein, a waste passiflora edulis peel derived in-situ N -doping porous carbon (PINPC) combined with three-dimensional hollow carbon cloth interlayer (3DHCI) was designed and constructed by facile simultaneous activation/carbonization. The abundant porous structure and nitrogen heteroatom doping of the PINPC not only significantly confine the soluble polysulfides through the physical and chemical adsorption, but also the high conductivity of the 3DHCI effectively accelerate the conversion reaction of polysulfides encapsulated in the unique hollow carbon skeletons. Owing to the synergetic enhancement of the PINPC and 3DHCI, the sulfur contents of the corresponding sulfur cathode composites are easily regulated from 70 wt% to 95 wt%, whilst exhibiting excellent electrochemical performances. The PINPC/S with a sulfur content of 70 wt% and 3DHCI interlayer obtains a high initial discharge capacity of 1032 mAh·g −1 and then retains 954 mAh·g −1 at 0.2 C after 200 cycles. At 2 C, a durable cycle life with capacity retention of 86% can be achieved up to 500 cycles. Even with an ultrahigh sulfur content of 95 wt%, the relatively high initial discharge capacity of 692 mAh·g −1 and capacity retention of 96 % are also achieved at 0.2 C after 200 cycles. This work offers a potential design for high-performance lithium sulfur batteries simultaneously with a high sulfur content.

N,S Co-Doped Carbon Nanofibers Derived from Bacterial Cellulose/Poly(Methylene blue) Hybrids: Efficient Electrocatalyst for Oxygen Reduction Reaction

Jing Liu,Yi-Gang Ji,Bin Qiao,Fengqi Zhao,Hongxu Gao,Pei Chen,Zhongwei An,Xinbing Chen,Yu Chen

Exploring inexpensive and highly efficient electrocatalyst to decrease the overpotential of oxygen reduction reaction (ORR) is one of the key issues for the commercialization of energy conversion and storage devices. Heteroatom-doped carbon materials have attracted increasing attention as promising electrocatalysts. Herein, we prepared a highly active electrocatalyst, nitrogen, sulfur co-doped carbon nanofibers (N/S-CNF), via in situ chemical oxidative polymerization of methylene blue on the bacterial cellulose nanofibers, followed by carbonization process. It was found that the type of nitrogen/sulfur source, methylene blue and poly(methylene blue), has significantly influence on the catalytic activity of the resultant carbon nanofibers. Benefiting from the porous structure and high surface area (729 m2/g) which favors mass transfer and exposing of active N and S atoms, the N/S-CNF displays high catalytic activity for the ORR in alkaline media with a half-wave potential of about 0.80 V, and better stability and stronger methanol tolerance than that of 20 wt % Pt/C, indicating great potential application in the field of alkaline fuel cell.Keywords:nitrogen sulfur co-doped carbon nanofibers;bacterial cellulose/poly(methylene blue) hybrids;oxygen reduction reaction;electrocatalyst

Catalytic hydrogenolysis of lignin to phenolic monomers over Ru supported N,S-co-doped biochar: The importance of doping atmosphere

Gao Wenran,Wang Ke,Wu Yishuang,Zhu Xun,Wu Yinlong,Zhang Shoujun,Li Bin,Huang Yong,Zhang Shu,Zhang Hong

Doping of heteroatoms into carbon materials is a popular method to modify their physicochemical structures and has been widely used in the fields of energy conversion and storage. This study aims to investigate the effect of doping atmosphere on the catalytic performance of nitrogen and sulfur co-doped biochar supported Ru in the production of phenolic monomers from lignin hydrogenolysis. The results showed that the catalyst prepared under CO2 atmosphere (Ru@CNS-CO2) was able to produce phenolic monomers from corncob lignin with a yield up to 36.41 wt%, which was significantly higher than that from the run over N2-prepared catalyst (Ru@CNS-N2). The characterization of the catalysts demonstrated that the CNS-CO2 support had a larger specific surface area, richer C=S and C-S groups, and higher oxygen content than CNS-N2, resulting in finer Ru particles and more Ru0 content on the CNS-CO2 support. The Ru@CNS-CO2 catalyst exhibited high activity in hydrogenation and fragmentation of β-O-4 linkages.

Molten Salt Thermal Treatment Synthesis of S-Doped V2CTx and Its Performance as a Cathode in Aqueous Zn-Ion Batteries

Weiyan Jiang,Huizhong Shi,Miao Shen,Rui Tang,Zhongfeng Tang,Jian-Qiang Wang

The lack of suitable cathode materials with a high capacity and good stability is a crucial problem affecting the development of aqueous Zn-ion batteries. Herein, a novel strategy for the modification of V2CTx through molten salt thermal treatment is proposed. In the novel route, S heteroatoms were introduced into V2CTx through a substitution reaction during the dissolution of Li2S in LiCl–KCl molten salts. Then, surface V2O5 was obtained through the in situ electrochemical charging/discharging of the S-doped V2CTx (MS-S-V2CTx) cathode. The assembled Zn/MS-S-V2CTx battery showed a high reversible discharge capacity of 411.3 mAh g–1 at a current density of 0.5 A g–1, an 80% capacitance retention after long cycle stability tests at 10 A g–1 for 3000 cycles, and a high energy density of 375.5 Wh kg–1 in 2M ZnSO4. Density functional theory calculations demonstrate that the improved electrochemical performance of the cathode can be attributed to the introduced S heteroatoms, which considerably reduced the ion diffusion energy barrier for Zn2+ ions and improved the stability of V2O5. This work provides a novel method to produce highly active and stable vanadium-based cathodes for aqueous Zn-ion batteries.