Soft Matter
·
2023
·Vol. 19
·期 30
·5711-5722
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IF 3.4
Yanrong Cheng,Wenlin Xu,Yaqiong Wang,Xia Guo
The PEG/salt aqueous two-phase system (ATPS) is the most common ATPS, but its application is still limited due to the restricted polarity difference between the two phases and the poor enhancement effect of adjuvants on ATPS performance so far. Unlike the adjuvants used so far, calixarenes can bind ions and molecules via multiple noncovalent interactions. In the present study, a water-soluble calixarene, p-sulfonatocalix[4]arene (SC[4]), was used for the first time as the adjuvant to improve the performance of the PEG 600/(NH4)2SO4 ATPS through multiple interactions. It is found that when the SC[4] and the SC[4]/imidazole ionic liquid ([Cnmim]Br) complex were used as the adjuvants, the formation of PEG 600/(NH4)2SO4 ATPS was enhanced, and the transfer of the extracts (including S-mandelic acid, L-tryptophan, and L-phenylalanine) into the PEG phase was promoted. Moreover, although the single [Cnmim]Br, a commonly used adjuvant, does not promote the migration of the target molecules into the polymer phase, the SC[4]/[Cnmim]Br complex is superior to SC[4] in enhancing the performance of the ATPS because the SC[4]/[Cnmim]Br aggregates enable more binding sites to combine with the extract. Besides, the partition coefficient of SC[4] in the PEG/trisodium citrate ATPS is much smaller than that in the PEG/(NH4)2SO4 ATPS, which is helpful for the recovery of extracts into the citrate phase.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Fengyu Tian,Mingzhao Zhu,Xuebiao Sun,Xuemin Yan
Selective CO2 photoreduction to valuable chemicals is promising for a carbon-neutral future and still remains a challenge. Herein, Zn vacancy-rich ZnO (Zn1–xO) nanoparticles were used as cocatalyst to construct a Zn1–xO/TiO2 nanostructure via the self-assembly process. The existence of Zn vacancies triggered the intimate contact between Zn1–xO and TiO2 through the Ti–O–Zn bonds. Theoretical and experimental results show that the hybridization of Zn1–xO and TiO2 resulted in the formation of a p–n heterojunction, leading to the enhanced separation efficiency of photoinduced electron–hole pairs. As a result, the optimized Zn1–xO/TiO2 nanocomposite exhibited nearly 100% selectivity of CO2-to-CO photoreduction, and the productivity was 4.2 times higher than that of pristine TiO2. In situ Fourier transform infrared spectra along with theoretical calculations were also conducted to investigate the mechanism of the selective photocatalytic CO2-to-CO process. It is concluded that the charge depletion on the TiO2 surface induced by the charge transfer from Zn1–xO to TiO2 can lower the energy barrier of CO* desorption and convert the endothermic CO* desorption process into an exothermic reaction step, thus triggering selective CO production. This work provides a new perspective on the rational fabrication of nanostructures for efficient and selective photocatalytic CO2 conversion through intermediate modulation.
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APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Shuo Li,Nan Yao,Lulu Fan,Zhengjia Li,Linyan Yang,Jie Cen,Xiaonian Li
How to break the activity-selectivity dependence in halonitrobenzene hydrogenation remains a challenge. In this work, Ni@C N/SiO 2 were synthesized and examined in the hydrogenation of p -chloronitrobenzene. It showed that the electron transferred from nitrogen doped carbon shell to Ni 0 core (core–shell synergistic effect) dominated the intrinsic activities of Ni@C N/SiO 2 with dual-reaction surfaces (H 2 dissociated on Ni 0 core, while p -chloronitrobenzene was hydrogenated on carbon shell) in the thiophene-free hydrogenation, leading to their higher turnover frequencies than Raney Ni catalyst. During the thiophene-involved hydrogenation, the adsorption of thiophene on Ni 0 changed its electron density and blocked the active sites. These enhanced the selectivity, but significantly reduced the activity for Raney Ni catalyst. Comparatively, the carbon shell protected Ni 0 core from thiophene adsorption so that the hydrogen dissociated on Ni 0 as usual. However, the adsorption of thiophene on the carbon shell reduced the available sites for p -chloronitrobenzene adsorption. Although Ni@C N/SiO 2 had lower activities in the thiophene-involved reactions than those of thiophene-free reactions, they achieved ∼100 % p-chloroaniline selectivities and 8-fold higher turnover frequencies than Raney Ni, breaking the activity-selectivity dependence. This reveals that the available sites on the carbon shell and the core–shell synergistic effect determine the thiophene-involved hydrogenation activities of Ni@C N/SiO 2 catalysts.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Di Fan,Jian Yang,Xinyi Xie,Meifang Cao,Li Xu,Xueqing Qiu,Qiyu Liu,Xinping Ouyang
Production of noncondensed lignin via lignocellulose fractionation usually shows limited yield. Promoting reaction conditions benefits lignin production but has negative effect on structural condensation and thus inhibits its value-added applications in depolymerization. To address this issue, a unique fractionation method was proposed using p -TsOH ( p -toluenesulfonic acid) in methanol under microwave irradiation to produce high-yield noncondensed lignin. It was found that microwave irradiation efficiently decreased the activation energy of lignin-carbohydrate complex (LCC) bonds cleavage from 102.1 to 63.8 kJ/mol and thereby facilitated lignin exfoliation from carbohydrates. And an effective α-alkoxylation reaction occurred between methanol molecular and C α -OH group in lignin, which protected β -O-4 linkages from condensation. After being fractionated under a relatively mild fractionation condition of 85 ℃ for 30 min, a promising lignin yield of 87.9 % can be obtained from poplar sawdust, with 91.8 % of ether bonds preserved. The obtained lignin can be selectively depolymerized into monophenols with a high yield of 42.0 %, which was 74.9 % to the theoretical yield. Besides, 94.3 % of cellulose was retained in solid part after fractionation, which can be efficiently converted into glucose with a yield of 98.5 % via enzymatic hydrolysis.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Xueping Sun,Peng Wei,Zhimin He,Fangyuan Cheng,Lin Tang,Qing Li,Jiantao Han,Jianhua He
Developing highly efficient and stable bifunctional electrocatalysts plays a crucial role in water splitting reaction. Benefiting from their abundant reserves, superior conductivity and excellent intrinsic catalytic properties, transition metal phosphides (TMPs) draw wide attentions in recent years. However, most of TMPs synthesis processes are still acomplicated and dangerous as the common use of toxic and flammable phosphorus sources. Herein, we propose a universal and scalable synthetic strategy to prepare a series of nanosized transition metal phosphide encapsulated in nitrogen-phosphorus co-doped carbon (TMP@NPC) catalysts by using green and inexpensive adenosine triphosphate (ATP) as a new phosphorus source. Profiting from the in situ and confined synthetic strategy, as-prepared TMP@NPC catalysts not only show nanosized dimension, but also endow extremely intimate interaction with N, P component derived from ATP. All as-prepared TMP@NPC catalysts exhibit excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities with small overpotentials and robust capabilities. Especially, the CoP@NPC displays the lowest overpotentials of 184.35 mV and 303 mV at 10 mA cm −2 toward HER and OER in alkaline electrolyte , respectively, which also exhibits outstanding stability (over 50 h at 10 mA cm −2 ) in both reactions. As a proof of further application, as-prepared CoP@NPC acting as both cathode and anode shows excellent performance in overall water splitting. This work not only highlights the green and general synthesis strategy importance in designing and constructing TMPs, but also reinforces the understanding of intimate interaction in coupled hybrid electrocatalysts.
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BIOCHEMICAL ENGINEERING JOURNAL
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2022
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IF 4.446
Jiaheng Wang,Nuo Zhang,Yawen Huang,Shunyi Li,Guimin Zhang
p -Coumaric acid (para-hydroxycinnamic acid, p -HCA), as a kind of natural active substance from plant cell walls, is widely used in medicine, food, and cosmetics with its antioxidant, anticancer, and other properties. Biological production of p -HCA can be achieved via one-step deamination of the L -tyrosine by tyrosine ammonia-lyase (TAL). Here, a new highly active TAL ( Fc -TAL) from Flavobacterium columnare was identified via gene mining and heterologous expression . The purified Fc -TAL completely converts 22 mM L -tyrosine to p -HCA under alkaline condition (pH 9.5–10.0) at 55 °C. To increase enzymatic recyclability and reduce the bioproduction cost, Fc -TAL was immobilized on a silica nanospheres through silica-binding peptides (SiBP2) at pH 10. In comparison to free enzyme , the immobilized TAL SiBP2 exhibited higher stability, over 50% activity was retained even after 10 consecutive catalytic cycles. Further experiments revealed that an aliquot of immobilized enzyme (about 200 mg TAL) can transform 20 g L -tyrosine into17.8 g p -HCA with 96% yields and 98% purity through 5 consecutive reaction cycles. Our studies not only provided a strategy for enzyme immobilization in alkaline condition, but also developed a green process for p -coumaric acid biosynthesis with the highest conversion rate and yield reported to date.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Xiaofang Yuan,Jianfei Xiao,Murat Yılmaz,Tian C. Zhang,Shaojun Yuan
Modification of biomass-derived porous biochar by heteroatomic doping can significantly improve CO 2 adsorption and capacitance performance of supercapacitors. In this study, a novel N, P co-doped porous biochar was developed by facile two-step pyrolysis using widely available and low-cost cornstalks as the carbon source, melamine as the N source, phytic acid as the P source, and a mild K 2 CO 3 as an activating agent. The pore structures and surface chemical characteristics of the as-prepared N, P co-doped cornstalk-derived porous biochar (abbreviated as NPCPB) were regulated by adjusting the pyrolysis temperature and K 2 CO 3 ratio. The as-prepared NPCPB-600-3 (600 represents an activation temperature of 600 °C, and 3 represents the mass ratio of K 2 CO 3 to the carbon composite precursor is 3) was characterized by various methods, and its CO 2 adsorption and electrochemical properties were studied. Results indicated that narrow micropores and N, P doping together determined the adsorption capacity, which was 3.11 mmol g −1 for CO 2 at 1 bar and 25 °C, with almost no decay after 10 consecutive cycles. NPCPB-600-2 had a superior specific capacity of 203.5 F g −1 at a current density of 1 A g −1 and an outstanding cycling stability with a good capacity retention of 106% after 5000 cycles at a high current density of 10 A g −1 . This work reveals that heteroatomically doped porous biochar from biomass has a promising application in CO 2 capture and supercapacitors.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Zhao Du,Huayi Cai,Zhonglu Guo,Zhiyuan Zhao,Jing Lin,Yang Huang,Chengchun Tang,Guifeng Chen,Yi Fang
Herein, a series of novel Ti 3 C 2 T x /p-BN heterojunctions with excellent photocatalytic activity have been prepared by combining one-dimensional (1D) porous BN fibers (p-BN) with high aspect ratio and two-dimensional (2D) ultrathin Ti 3 C 2 T x MXenes for photocatalytic conversion of CO 2 -to-CO. Our results show that the optimized photocatalyst can photo-reduce CO 2 to generate CO under UV light with CO yield of 22.53 μmol g −1 h −1 , which is 4.3 and 20.1 times of p-BN (5.23 μmol g −1 h −1 ) and Ti 3 C 2 T x (1.23 μmol g −1 h −1 ), respectively. We demonstrate that the Ti 3 C 2 T x /p-BN heterojunction can combine the efficient CO 2 adsorption of porous p-BN and excellent electronic conductivity of Ti 3 C 2 T x . Moreover, the interfacial Ti-O-B bonds lead to strong interaction between p-BN and Ti 3 C 2 T x , resulting in the formation of Schottky heterojunction. The synergistic effect not only enables the adsorption of CO 2 by Ti 3 C 2 T x /p-BN heterojunction higher than p-BN, but also accelerates the transfer and separation of photogenerated carriers in p-BN, which finally exhibits promoted CO 2 photocatalytic activity. The present work pioneer the application of Ti 3 C 2 T x /p-BN heterojunction in photocatalytic CO 2 reduction and further guides the design of noble-metal-free photocatalysts.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Cheng Wang,Siqi Huo,Guofeng Ye,Pingan Song,Hao Wang,Zhitian Liu
Epoxy resin (EP) features superior comprehensive performances, but inherent flammability seriously limits its industrial applications. Current flame-retardant strategies often bring about enhanced flame retardancy but deteriorated mechanical, thermal and optical properties and neglect flame retardant durability. Herein, a phosphorus/silicon-containing polyethylenimine (PES) is designed as a multifunctional curing agent for EP. Replacing polyethylenimine (PEI) with PES maintains high visible light transmittance of EPs and improves the UV-blocking properties. The EP cured by 30 wt% PES (EP/30PES) exhibits enhanced mechanical properties compared with the EP cured by 15 wt% PEI (EP/15PEI). EP/30PES achieves a limiting oxygen index (LOI) of 35.0% and a UL-94 V-0 rating, and its peak smoke release rate (PSPR) reduces by 63.8% relative to that of EP/15PEI. Hence, the great flame retardancy, smoke suppression and mechanical performances of EP/30PES enable it to outperform previous flame-retardant EP/aliphatic amine counterparts. Meanwhile, EP/30PES shows durable flame retardancy, which still achieves a UL-94 V-0 classification after acid/alkali/aging resistance tests. This work provides an advanced design of multifunctional curing agents to create durable fire-safe EPs with great UV-shielding and mechanical performances.
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ACS Applied Materials & Interfaces
·
2022
·
IF 10.383
Xiangbao Yuan,Haiyun Li,Jing Fan,Lin Zhang,Feng Ran,Menglei Feng,Peiyuan Li,Weixiang Kong,Shijian Chen,Zhigang Zang,Shuangpeng Wang
The effect of substitutional metal dopants in NiOx on the structural and electronic structures is of great interest, particularly for increasing the p-type conductivities as a hole transport layer (HTL) applied in perovskite solar cells (PSCs). In this paper, experimental fabrications and density functional theory calculations have been carried out on Cd-doped NiOx films to examine the effect of divalent doping on the electronic and geometric structures of NiOx. The results indicate that divalent Cd dopants reduced the formation energy of the Ni vacancy (VNi) and created more VNi in the films, which enhanced the p-type conductivity of the NiOx films. In addition, Cd doping also deepened the valence band edge, reduced the monomolecular Shockley–Read–Hall (SRH) recombination losses, and promoted hole extraction and transport. Hence, the PSCs with Cd:NiOx HTLs manifest a high efficiency of 20.47%, a high photocurrent density of 23.00 mA cm–2, and a high fill factor of 79.62%, as well as negligible hysteresis and excellent stability. This work illustrates that divalent elements such as Cd, Zn, Co, etc. may be potential dopants to improve the p-type conductivity of the NiOx films for applications in highly efficient and stabilized PSCs.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Dexin Xu,Jing Yao,Xinzhi Ma,Yan Xiao,Chi Zhang,Wei Lin,Hong Gao
Electrochemical water splitting, the most direct and clean method used for the production of hydrogen, requires highly efficient bifunctional electrocatalysts that can accelerate hydrogen evolution reactions (HER) and oxygen evolution reactions (OER) by overcoming their kinetics barriers. Herein, self-supported F, N codoping CoP nanosheets (denoted as FN-CoP NS) are prepared as efficient and stable bifunctional electrocatalysts. Codoping of F and N neutralizes the electronegativity of surface P-O by cleaving the Co-P-O of non-metallic P sites on the surface (O derived from the surface oxidation). This contributes to an increased Co 2+ content with considerable adjustable electronegativity and also optimizes HER and OER processes. As a result, FN-CoP NS requires 66 and 241 mV overpotentials to deliver the current density of 10 mA cm −2 during HER and OER, respectively. A full water electrolyzer equipped FN-CoP NS as both cathode and anode only require 1.57 V to drive the current density of 10 mA cm −2 and to sustain 50 mA cm −2 for 48 h. This work adjusts the electronic structure of metal phosphides by a double anion codoping strategy, which provides a reference value for the rational design of efficient bifunctional electrocatalysts.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Chuankun Yin,Aimal Khan,Qiaohui Gao,Quan Li,Xiaoyun Zhou,Xiuying Liu,Aihua Xu,Xiaoxia Li
Recently, the development of efficient mixed metal oxide catalysts for organic pollutants degradation via peroxymonosulfate (PMS) activation is a hot topic in the area of wastewater treatment . In this work, the silver-copper mixed-oxide, Ag 2 Cu 2 O 3 (ACO) was reported for the first time as a highly active catalyst for removing organic pollutants in the presence of PMS. ACO was successfully synthesized from Ag + and Cu 2+ ions at 60 °C, and its structure was strongly influenced by the temperature. The catalyst could almost completely remove p -nitrophenol and other pollutants with 0.65 mM PMS after 20 min, and also exhibited satisfactory stability and recyclability. The system efficiency was shown to vary with the concentration of PMS and catalyst, as well as solution pH. Scavenger experiment and EPR analysis indicated that radicals produced by the oxidation of Ag(I) and Cu(I) with PMS could promote degradation reaction. The synergistic effect between Cu and Ag in the bimetallic catalyst was demonstrated to contribute to the high performance: Cu(II)-O-Ag(I) bonds promote the conversion of Cu(II) species to Cu(I) through reaction with PMS, and facilitate the oxidation of Cu(I) and Ag(I) by PMS to generate active radicals. The study provides a feasible strategy to design efficient and stable bimetal oxide catalysts for PMS activation.
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