Nature Communications
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2023
·Vol. 14
·期 1
·1-12
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IF 16.6
Jung Sinyeong,Cheung Wai-Lung,Li Si-jie,Wang Min,Li Wansi,Wang Cangyu,Song Xiaoge,Wei Guodan,Song Qinghua,Chen Season Si,Cai Wanqing,Ng Maggie,Tang Wai Kit,Tang Man-Chung
The realization of operationally stable blue organic light-emitting diodes is a challenging issue across the field. While device optimization has been a focus to effectively prolong device lifetime, strategies based on molecular engineering of chemical structures, particularly at the subatomic level, remains little. Herein, we explore the effect of targeted deuteration on donor and/or acceptor units of thermally activated delayed fluorescence emitters and investigate the structure-property relationship between intrinsic molecular stability, based on isotopic effect, and device operational stability. We show that the deuteration of the acceptor unit is critical to enhance the photostability of thermally activated delayed fluorescence compounds and hence device lifetime in addition to that of the donor units, which is commonly neglected due to the limited availability and synthetic complexity of deuterated acceptors. Based on these isotopic analogues, we observe a gradual increase in the device operational stability and achieve the long-lifetime time to 90% of the initial luminance of 23.4 h at the luminance of 1000 cd m −2 for thermally activated delayed fluorescence-sensitized organic light-emitting diodes. We anticipate our strategic deuteration approach provides insights and demonstrates the importance on structural modification materials at a subatomic level towards prolonging the device operational stability.
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ACS Sustainable Chemistry & Engineering
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2023
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IF 8.4
Tianbo Zhou,Bing Wang,Xueshuai Wang,Haoran Sun,Yi Liu,Liuchun Zheng
The serious environmental pollution caused by nonbiodegradable plastics has led to an increased demand for biodegradable plastics. Poly(butylene succinate) (PBS) is a very essential biodegradable polymer because of its good combined properties. But its drawbacks of low impact strength and lack of functionality restrain its application. In this work, polydimethylsiloxane (PDMS) is used to synthesize the diatom-like structure poly(butylene succinate)-b-polydimethylsiloxane (PBSP), and the effect of molecular weight on the structure and properties is investigated systematically for the first time. The unique layered structure limited by the covalently connected blocks endowed PBSP with an excellent combined performance. The resulting PBSP possesses good thermal and mechanical properties. The mechanical properties improved substantially; especially, the impact strength increased evidently from 34.6 J/m of PBS to 162.5 J/m of PBSP. Furthermore, PDMS blocks endow the copolymers with good hydrophobicity and antismudge and self-healing properties, which greatly broadens the application range of the PBS materials. The surface analysis and Flory–Huggins solution theory testified that the PDMS blocks with higher molecular weight preferentially enriched the surface and sublayer of the material, due to the huge difference in solubility parameters between PBS and PDMS. PBSP with regulatable mechanical properties and functions could be obtained by changing the molecular weight of the PDMS blocks.
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Molecular Catalysis
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2023
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IF 4.6
Donglin Huang,Wulin Song,Hongmei Zhao,Meng Li,Liang Wei,Hongxi Zhang
There are limited renewable sources of aromatic chemicals, with lignin being one of the most prominent, accounting for approximately 30% of the planet's organic carbon. Due to its intricate and irregular structure, lignin is recalcitrant to chemical conversion, often resulting in low yields of mixtures of products when it is depolymerized. This study synthesized a CeO 2 /AC catalyst via an impregnation technique and then explored its ability to depolymerize lignin via an oxidation-reduction strategy. The CeO 2 /AC catalyst efficiently depolymerized lignin by an oxidation-reduction strategy. At 200 °C, an argon pressure of 1 MPa, and a reaction time of 4 h, the conversion of the lignin model compound reached 98.5%. When using lignin derived from poplar, birch, pine, and cotton stalk, the total yields of phenolic monomers were 36.2 wt.%, 31.2 wt.%, 17.4 wt.%, and 12.1 wt.%, respectively. The CeO 2 /AC catalyst exhibited a higher surface oxygen vacancy concentration than CeO 2 , which was crucial for facilitating the hydrogenolysis of lignin.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2023
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IF 11.4
Binbin Shao,Jing Deng,Hongyu Dong,Shuchang Wang,Enchao Li,Xiaohong Guan
Recent research has primarily focused on the utilization of reductants as activators for Fe(VI) to generate high-valent iron species (Fe(IV)/Fe(V)) for the degradation of emerging organic contaminants (EOCs). However, a significant drawback of this approach arises from the reaction between reductants and ferrates, leading to a decrease in oxidation capacity. This study introduces a novel discovery that highlights the potential of the iron(III)-(1,10-phenanthroline) (Fe(III)-Phen) complex as an activator, effectively enhancing the degradation of EOCs by Fe(VI) and augmenting the overall oxidation capacity of Fe(VI). The degradation of EOCs in the Fe(VI)/Fe(III)-Phen system is facilitated through two mechanisms: a direct electron transfer (DET) process and electron shuttle action. The DET process involves the formation of a Phen-Fe(III)–Fe(VI)* complex, which exhibits a stronger oxidation ability than Fe(VI) alone and can accept electrons directly from EOCs. On the other hand, the electron shuttle process utilizes Fe(III)-Phen as a redox mediator to transfer electrons from EOCs to Fe(VI) through the Fe(IV)/Fe(III) or Fe(IV)/Fe(II)/Fe(III) cycle. Moreover, the Fe(III)-Phen complex can improve the utilization efficiency of Fe(V) by preventing its self-decay. This study’s findings may present a viable option for utilizing an effective catalyst to enhance the oxidation of EOCs by Fe(VI) and Fe(V).
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CHEMICAL ENGINEERING SCIENCE
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2023
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IF 4.7
Yuxin Zhou,Minghua Liu,Yuancai Lv,Hong Guo,Yifan Liu,Xiaoxia Ye,Yongqian Shi
In this work, a lignin phenolic carbon foam (LCF) with preferable smoke suppression performance was fabricated by substitute 10 wt.% and 30 wt.% phenol with modified lignin in the traditional process. The result showed that the LCF 600 s (LCFs carbonized at 600℃) with different lignin percentages showed better smoke suppression performance than the traditional phenolic carbon foam (CF 600 ). The peak smoke production rate (pSPR) and total smoke release (TSR) of LCF 600 s decreased by 6.90%∼48.28% and 80.91%∼96.28%, and the peak CO production rate and CO yield decreased by 41.17%∼70.59% and 53.80%∼77.79%, respectively. Besides, LCF 1-10-600 and LCF 2-30-600 displayed the best smoke suppression performance (0020, 0.0015 m 2 /s of pSPR and 0.61, 2.76 m 2 /m 2 of TSR, respectively). Since the introduced modified lignin significantly increased the amount of benzene rings in the forms, the degree of graphitization of the resulted carbon foams greatly improved, leading to better smoke suppression performance. Furthermore, the added lignin facilitated the preservation of the carbon layer, resulting in reducing smoke production consequently.
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CHEMOSPHERE
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2023
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IF 8.8
Huiwang Dai,Jingyi Zhu,Fanxu Meng,Daohui Lin,Wenjun Zhou,Dingjiang Chen,Ming Zhang,Qingqing Wang
In this study, Cu hybridization coupling oxygen defect engineering was adopted to synthesis of CuNiFe layered double oxides (CuNiFe-LDOs) in peroxymonosulfate (PMS) activation for degradation of methyl 4-hydroxybenzoate. The morphology and crystal structure of CuNiFe-LDOs was characterized in detail, which exhibited regular layered-structure at a Cu:Ni doping ratio of 1:1 and annealing temperature of 400 °C, and presented the crystal of Cu x O@Fe 3 O 4 –NiO. Besides, the X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) results demonstrated that abundant oxygen vacancies (OVs) and low oxidation state Cu species were composed in CuNiFe-LDOs400. The Cu 1·5 Ni 1·5 Fe 1 -LDOs400/PMS system showed excellent catalytic performance toward the degradation of butyl 4-hydroxybenzoate (BuP), and resistant to the effect of pH value and background inorganic anions. Based on quenching experiments and EPR measurements, singlet oxygen ( 1 O 2 ) was identified as the dominant active species during the heterogeneous catalytic process, which was generated by the synergistic interaction between OVs-Cu(I) site and PMS . In this process, the electron-drawing property of OVs promoted the adsorption of PMS molecule on Cu(I) site, followed by the accumulation of electron and cleavage of O–O bond to generate intermediate oxygen radical species, which donated one electron to eventually generate singlet oxygen.
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FUEL
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2023
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IF 7.4
Lixia Li,Zhechao Huang,Fenghao Shu,Ying Gao,Jinxing Long
Novel techniques for upgrading heavy lignin bio-oil, the phenolic oligomer from lignin depolymerization, are of great significance for achieving better utilization efficiency of carbon element in lignin. In this study, we proposed an efficient approach for producing high-quality oxygen-containing fuel from the renewable lignin bio-oil via the C-O bond cleavage and the subsequent hydrogenation over the Cu and Ni supported on alkaline MgO . Noticeably, the optimized Cu 6 Ni 20 /MgO resulted in inspiring yields of ethylbenzene (88.6%) and cyclohexanol (98.3%) from lignin dimers, and a colorless fuel with a high-heating value of 31.4 MJ kg −1 from the realistic lignin bio-oil. The results of catalyst characterization also unveiled that introducing Cu species reduced the formation of NiMgO x solid solution, which increased the content of Ni 0 and consequently promoted the performance of upgrading lignin bio-oil. Furthermore, the recondensation of phenolic oligomers could be effectively restrained by the alkaline MgO. In addition, a plausible mechanism was proposed. Therefore, this work opens a promising avenue to designing efficient strategies for utilizing the heavy components from lignin depolymerization.
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RENEWABLE ENERGY
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2023
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IF 8.7
Zhipeng Tian,Xiaoxin Chen,Tao Liu,Junyao Wang,Chao Wang,Riyang Shu,Jianping Liu,Ying Chen
Selective hydrodeoxygenation (HDO) of phenolic compounds derived from the pyrolysis lignin-oil to desired products is a promising route in the high-value utilization of biomass-derived products. As high as 99.99% guaiacol conversion and 96.70% cyclohexanol selectivity are obtained over optimized Co/1 K–Al 2 O 3 catalyst, which are better than those Co-based catalyst reported in previous studies. Highly dispersed Co particles provide more metal active sites and better chemisorption of guaiacol molecules, which promotes HDO activity. Importantly, with the increase amount of K species doped in Al 2 O 3 support, the total amount of acid sites on catalyst decreases and the strong acid site disappear, which inhibits unwanted conversion of cyclohexanol to the byproduct cyclohexane. It can be found that with proper amount of acid sites and strength, the selectivity of cyclohexanol can be maximized during selective HDO reaction of guaiacol. The kinetic study also shows that the activation energy from cyclohexanol to cyclohexane increases from 62.08 kJ/mol over Co/Al 2 O 3 catalyst to 86.11 kJ/mol over Co/1 K–Al 2 O 3 catalyst, implying that the reaction barrier improves, which hinders further removal of hydroxyl group on cyclohexanol. Besides, selective HDO reactions using other typical phenols as substrates over Co/1 K–Al 2 O 3 catalyst were performed and good alkyl cyclohexanols selectivities are observed.
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ChemSusChem
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2023
·
IF 8.4
Xiangchen Kong,Chao Liu,Hongyun Zeng,Yuyang Fan,Huiyan Zhang,Rui Xiao
Graphical Depolymerization of Kraft lignin to value-added monomers can significantly enhance the profitability of lignocellulosic biorefinery. In this work, the efficient transformation of highly condensed Kraft lignin to valuable aromatic monomers through stepwise alcoholysis and zeolite-catalyzed methylene linkage cleavage is disclosed. Lignin is an aromatic polymer that constitutes over 30 wt% of lignocellulosic biomass and is the most important source of renewable aromatics in nature. The global paper industry generates more than 70 million tons of Kraft lignin annually. Depolymerization of Kraft lignin to value-added monomers can significantly enhance the profitability of biorefinery. However, the method is impeded by the severe condensation of Kraft lignin during the pulping process, which forms robust C−C bonds and results in low monomer yields. In this study, we present a stepwise approach for producing valuable aromatic monomers from Kraft lignin through the cleavage of both C−O and C−C bonds. The approach initiated with complete cleavage of C−O bonds between lignin units within Kraft lignin through alcoholysis in isopropanol, resulting in a monomer yield of 8.9 %. Subsequently, the selective cleavage of methylene linkages present in the residual dimers and oligomers was achieved with commercial MCM-41 zeolite in the same pot, proceeding with an additional monomer yield of 4.0 %, thereby increasing the total monomer yield by 45 %. This work provides an avenue for increasing the depolymerization efficiency of Kraft lignin.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
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IF 4.2
Zheng Huang,Jianna Bao,Xianming Zhang,Wenxing Chen
The incorporation of ionic groups (sodium sulfonate group) in cationic dyeable polyesters (CDPs) leads to alterations in melt flow behaviors and corresponding effects on the conventional production process compared with poly(ethylene terephthalate) (PET). In this study, a range of CDPs were synthesized with a wide range of sodium-5-sulfo-bis(hydroxyethyl)-isophthalate (SIPE) contents, and their structures, properties, and rheological behaviors were comprehensively investigated. The thermal stability of CDPs decreased, while the glass transition temperature initially decreased and then increased with an increase in SIPE content. Several rheological tests were performed, and the time–temperature superposition principle was utilized to give an in-depth analysis of ionic aggregations and internal structures of CDPs. A more complex rheological behavior of CDPs was observed due to the ionic aggregation effects aroused from the strong polarity of sodium sulfonate groups. Based on temperature scans, small amounts of SIPE would act as a plasticizer, reducing the complex viscosity (η*) of CDPs. As the SIPE content increased, the η* of CDPs increased, and the linear viscoelastic interval became narrower, indicative of the formation of ionic aggregates, and this structure was also verified by the results obtained from extensional rheology. Time–temperature superposition began to fail when the SIPE concentration rose further, confirming that ionic aggregation clusters emerged. This work may shed light on the understanding of design and structure–property relationships of PET ionomers.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2023
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IF 4.2
Haihong Wang,Huiyan Ma,Yan Li,Lin Cheng,Jucai Yang,Juming Liu
Efficient, low-cost, and easily scalable wide-spectral-responsive TiO2 photocatalysts are still extremely desired in driving photocatalytic degradation toward practical applications. In this work, a modified TiO2 with a narrow band gap and low valence band (VB) (CC-OV-TiO2) was successfully synthesized based on a facile sol–gel and low-temperature carbonization process, which can be used for the photocatalytic degradation and mineralization of a wide range of phenols. The results show that the interstitial doping of carbonates and the modification of surface oxygen vacancy (OV) defects together contribute to the formation of the VB tail states, which substantially narrow the band gap of TiO2 and widen the photoresponse range. Meanwhile, the carboxylated carbon species induce a substantial downward shift of the VB edge through coordination of the electron-withdrawing carboxyl groups, which further enhances the oxidation ability of the photogenerated holes. Accordingly, CC-OV-TiO2 with a narrow band gap and low VB exhibits superior and stable photocatalytic performance.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
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IF 22.1
Caizhi Lv,Pengchong Jiao,Hui Xin,Lan Wu,Gangfeng Ouyang,Xiandeng Hou
Insulator hydroxyapatite (HAp) was chosen as a candidate to construct full-spectrum photocatalyst. Glucose as a functional precursor was incorporated into HAp by coprecipitated method, and the glucose-modified HAp was then calcined under nitrogen atmosphere. With the loss of OH - group in HAp and the decomposition of glucose during the calcination, oxygen vacancies (OVs) for regulating the band gap, graphitic carbon (GC) as a good electron acceptor, and a channel for rapid carrier separation via the C-O-Ca forming between OV-HAp and GC can be simultaneously achieved. The as-prepared OV-HAp/GC displayed full-spectrum response and rapid separation of carriers. Moreover, it showed high degradation performance for 2, 4-dichlorophenol (2, 4-DCP), phenol, and tetracycline under visible, NIR, and full-spectrum. This strategy is not only facile, but also exhibits a certain universality. This work opens a new window for full-spectrum photocatalysts construction based on insulators, and large-scale production for practical use can be expected.
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