ChemistrySelect
·
2023
·Vol. 8
·期 16
·e202300902
·
IF 2.1
Panli Liu,Shengbin Shi,Ruiping Wei,Lijing Gao,Jin Zhang,Guomin Xiao
Graphical P-Zr-SBA-15 catalyst with bifunctional acidity was synthesized by introducing Zr 4+ into the mesoporous material SBA-15 structure for intra skeleton modification, and then impregnated with phosphoric acid solution to modify the outer skeleton. The catalyst exhibits excellent catalytic activity, good thermal stability, and recoverability in the preparation of furfural. A series of bifunctional P-Zr-SBA-15 catalysts with Lewis acid and Brønsted acid sites were prepared by modifying mesoporous material SBA-15 with Zr 4+ and phosphate group, which were used in the conversion of xylose and xylan into furfural. The structure and acidic characteristics of the catalyst were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, N 2 adsorption desorption, scanning/transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, NH 3 temperature programmed desorption, and pyridine adsorption infrared spectroscopy. The effects of different process parameters on the catalytic performance of the catalyst were studied. when using the xylose and xylan as substrates, the furfural yield were 80.3 % and 68.8 % under the optimal conditions in the H 2 O (NaCl) /toluene (3/3 mL) biphasic solvent system, respectively, and 52.5 % furfural yield was obtained using xylose as substrate in aqueous system. In addition, the catalyst has good thermal stability and easy recovery in the recycling experiment.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Yuan-li Wang,Tong-hui Yang,Song Yue,Hang-bo Zheng,Xiao-pan Liu,Peng-zhao Gao,Hang Qin,Han-ning Xiao
Composition optimization, structural design, and introduction of external magnetic fields into the catalytic process can remarkably improve the oxygen evolution reaction (OER) performance of a catalyst. NiFe2O4@(Ni, Fe)S/P materials with a heterogeneous core–shell structure were prepared by the sulfide/phosphorus method based on spinel-structured NiFe2O4 nanomicrospheres. After the sulfide/phosphorus treatment, not only the intrinsic activity of the material and the active surface area were increased but also the charge transfer resistance was reduced due to the internal electric field. The overpotential of NiFe2O4@(Ni, Fe)P at 10 mA cm–2 (iR correction), Tafel slope, and charge transfer resistance were 261 mV, 42 mV dec–1, and 3.163 Ω, respectively. With an alternating magnetic field, the overpotential of NiFe2O4@(Ni, Fe)P at 10 mA cm–2 (without iR correction) declined by 45.5% from 323 mV (0 mT) to 176 mV (4.320 mT). Such enhancement of performance is primarily accounted for the enrichment of the reactive ion OH– on the electrode surface induced by the inductive electric potential derived from the Faraday induction effect of the AMF. This condition increased the electrode potential and thus the charge transfer rate on the one hand and weakened the diffusion of the active substance from the electrolyte to the electrode surface on the other hand. The OER process was dominantly controlled by the charge transfer process under low current conditions. A fast charge transfer rate boosted the OER performance of the catalyst. At high currents, diffusion exerted a significant effect on the OER process and low OH– diffusion rates would lead to a decrease in the OER performance of the catalyst.
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Energy Storage Materials
·
2023
·
IF 20.4
Chengyao Zhao,Yiming Lin,Qiaoyan Lin,Qi Liu,Yujing Liu,Zhongqiu Liu,Anguo Ying
Aqueous zinc-ion hybrid capacitors (ZIHCs) are a promising new type of energy storage device, but there is a plight that the unsatisfactory Zn 2+ storage capability of carbonaceous cathodes limits further application. To address this issue, desolvation strategy is employed to tailor the solvation sheath of Zn 2+ in the ultra-micropores (0.59 nm) nanospheres , where H 3 PO 4 acts as phosphorus source for forming C-P bonds and enhancing C=O bonds to further reduce the desolvation energy barrier. In practical application, a quasi-solid-state flexible ZIHC is constructed, which provides a battery-level energy density (293.4 Wh kg −1 ) at a power density (180 W kg − 1 ) and a remarkable capacity retention of 93.4 % after 10 000 cycles. Electrochemical analyses, DFT calculations and structural characterization reveal that ultra-microporous is proved to be a prerequisite for C-P/C=O that are expected to further deplete solvent molecules within a Zn 2+ solvation sheath. Also, the coupling effect between the strong adsorption of Zn 2+ by C-P/C=O and the hydrophobic effect of C-P play an important role in facilitating desolvation process. This work creates a precedent for the application of ultra-microporous carbon materials in ZHICs and provides a brand-new approach for breaking the bottleneck of the low energy density and poor lifespan of ZHICs.
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Solar RRL
·
2023
·Vol. 7
·期 10
·2300023
·
IF 7.9
Yaju Wei,Guoqiang Yu,Guohui Luo,Wang Fu,Wuqi Liu,Tao Wang,Haonan Xu,Xiaoping Wu,Lingbo Xu,Ping Lin,Xiaodong Zhu,Xuegong Yu,Peng Wang,Can Cui
Molybdenum oxide (MoO 3− x , x < 3) has been successfully used as an efficient hole-selective contact material for crystalline silicon heterojunction solar cells. The carrier transport capability strongly depends on its work function, that is, oxygen vacancies; however, there are lack of effective methods to modulate the multiple oxidation states. Herein, the oxidation states of solution-processed MoO 3− x by doping Nb 5+ to improve its hole-selective contact performance with silicon are tuned. With the optimum doping concentration of 5%, both the reduced Mo 5+ and oxygen vacancies increase, resulting in a decrease in the contact resistivity between the MoO 3− x film and p -type silicon from 161.1 to 62.9 mΩ·cm 2 and an increase of the effective carrier lifetime from 165.4 to 391.0 μs simultaneously. Similarly, the doping of Ta 5+ or V 5+ in MoO 3− x improves the passivated contact performance with silicon, while the former increases the concentration of oxygen vacancies and the latter reduces it. The solar cell with the structure of Ag/MoO 3− x :Nb/ p -Si exhibits a conversion efficiency of 18.37%, which is the highest so far reported for the solution-processed MoO 3− x /silicon heterojunction. This work demonstrates a feasible strategy of tuning hole selectivity in MoO 3− x by doping for high-efficiency solar cells and other optoelectronic device applications.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Guiyang Yu,Ke Gong,Chuanwang Xing,Lan Hu,Haibin Huang,Lejie Gao,Debao Wang,Xiyou Li
Organic semiconductor under photoexcitation could generate abundant strong-binding Frenkel excitons and inevitably suffer from low dissociation efficiency (<1%) and poor mobility ability, which severely suppresses the efficient utilization of photogenerated charges and corresponding activity. Herein, a dual P-doping strategy is proposed in bay and corner sites implanted polymeric carbon nitride (PCN-D) for visible-driven H 2 O 2 production. The dual P doping breaks localized electron state around original symmetric heptazine units and weakens the binding energy between electrons and holes, increasing dissociation efficiency to reach 11.9% with 20-fold improvement. In addition, the conductivity ability of PCN-D, including formed carrier charge concentration and mobility, achieves 13-fold and 7-fold improvement, which facilitates the charge transfer and separation. The proposed dual doped-P-site strategy, with the blessing of porous structure, provides plentiful active center for effective adsorption and activation of O 2 molecule, further accelerating reaction progress and achieving six-times increase of photocatalytic H 2 O 2 production rate. This work provides in-depth insight into the importance of dual P-doping to optimize kinetic behavior of photogenerated charges and opens an avenue to the multiscale doping-modulation of semiconductor with high efficiency solar energy conversion.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ruihan Du,Kunkun Xiao,Shuiyuan He,Yang Wang,Chunli Kang
In this study, Bi 4 Ti 3 O 12 nanosheets and flower-like MoS 2 were synthesized by hydrothermal method and compounded into p-n heterojunctions with 2 D– 2 D structure. The stable p-n heterojunctions exhibit excellent visible-light-driven catalytic activity through effective electron/hole (e - /h + ) separation, which generates a built-in electric field between the two components, accelerates the separation efficiency of photogenerated charges between the materials, and reduces the photogenerated electron-hole complexation efficiency. The methylene blue (MB) was degraded under simulated sunlight conditions, and the removal efficiency of MB at an initial concentration of 10 mg/L could reach 91.1% within 270 min. HRTEM and microstructural study revealed microscopic close interaction between the two phases, which can shorten the transport path of photogenerated electron-hole pairs, and optical measurement studies show a significant improvement in visible light absorption and charge carrier separation due to the formation of heterojunctions. Free radical quenching experiments and electron paramagnetic resonance (EPR) showed that the main active substances are·OH and·O 2 - , and photogenerated h + is also involved in the photocatalytic reaction process. The system also shows good degradation efficiency in different water matrices, five-cycle experiments, and good structural stability elucidate its potential application in degrading emerging pollutants for water purification.
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OPTICAL MATERIALS
·
2023
·
IF 3.9
Jia Li,Jianfeng Zheng,Xingmin Liu,Yatao Yang,Xiaojin Han,Zhanggen Huang
Photoelectrochemical reduction of CO 2 with H 2 O into syngas (H 2 /CO) is considered as an important platform to organic chemicals, which can effectively alleviate the greenhouse effect and energy dependence. We synthesized SnO/g-C 3 N 4 p-n junction catalyst with matched energy band, which shows enhanced light absorption performance and photogenerated charge separation efficiency. The M − S plots verified the successful construction of p-n type heterojunctions , and the investigations of LSV , EIS , PL and transient photocurrents test indicate that the recombination rate of charge is well inhibited by the design of p-n heterojunction. In this work, the syngas derived from PEC reduction of CO 2 and H 2 O is achieved by the SnO/g-C 3 N 4 photocathode with a total FE of 70% at an external bias of −1.5 V. In addition, the H 2 /CO molar ratio can be tuned from 1.5 to 10 by controlling the applied voltage. The study may inspire a new thought for the design of high-performance photoelectric catalyst and a promising strategy for PEC CO 2 reduction to valuable carbon-based compounds.
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Surfaces and Interfaces
·
2023
·
IF 6.2
Jie Jiang,Yuqiang Ding
As a widely used semiconductor photocatalyst , TiO 2 has been explored in organic compounds hydrogenation. In this study, the hydrogenation of C=N bonds on the surface of TiO 2 was accomplished for the first time utilizing Cu 2 O/TiO 2 type-II (p-n) heterojunction . The probe reactions, hydrogenation of N -benzylphenylamine with benzyl alcohol, and N -methylation of amines with methanol exhibited that the hydrogenation of C=N bonds on TiO 2 surface can be achieved through borrowing hydrogen reaction (BH, alcohols as hydrogen source). Additionally, the BH reaction rate could be improved by adding external H + to the reaction system. The catalytic activity of Cu 2 O/TiO 2 was discovered to remain at an efficient level even after six reaction cycles.
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APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Jian Wang,Yunchuan Xie,Jingjing Liu,Zhicheng Zhang,Yanfeng Zhang
Poly(vinylidene fluoride) (PVDF) based polymer/ceramic nanocomposites for high energy density dielectrics have long been plagued by their low discharging efficiency (40–60%), which originates from the matrix with high bulk ferroelectric relaxation and the high-k ceramics with large conduction loss. In this work, a linear-like PVDF-based polymer dielectric is synthesized through grafting poly(methyl methacrylate) (PMMA) onto main chains of poly(vinyl fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) terpolymer via an atom transfer radical polymerization (ATRP) process. PMMA grafted terpolymer (P(VDF-TrFE-CTFE)-g-PMMA) shows linear-like dielectric characteristics accompanied with greatly enhanced discharging efficiency of ∼80% under 250 MV/m, which is over 100% higher than that of pristine terpolymer. To further improve its breakdown strength and discharging efficiency, the grafted terpolymer are then compounded with ultrasonic-exfoliated mica nanosheets ( e Mica) by solution-cast method. Thanks to the low hysteresis loss of linear-like dielectric matrix and the high insulating 2D mica nanosheets, the composite with the highest discharging efficiency of ∼78% under 250 MV/m is achieved. The maximum energy density of the optimized composite reaches 9.6 J/cm 3 , which is nearly 290% that of the pristine terpolymer. Besides, its discharging efficiency is about 74% under 450 MV/m, which is much more advantageous than the other PVDF-based polymer/ceramics composite dielectrics. This work suggests that utilizing polymer matrix with linear dielectric property and fillers with high insulating 2D structure might be a facile strategy to achieve composite dielectrics with simultaneously high energy density and high discharging efficiency.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Lingjiao Li,Jing Xu
The effect of reaction solvent on the hydrogen evolution activity of novel CoS 2 /FeLaO 3 -4(CS/FLO-4) p-n heterojunction photocatalysts, synthesized using the solvothermal method, was assessed. The highest activity under visible light irradiation was recorded for the CS/FLO-4 catalyst prepared in ethanol. In fact, after 5 h of reaction, the H 2 -yield of the ethanol composite (279.7 μmol) was found to be 5.2 and 150.2 times greater than that of CoS 2 microspheres and FeLaO 3 nanoparticles, respectively. Time-resolved fluorescence (TRF) and photoelectrochemical experiments confirmed the effectiveness of space charge separation in the ethanol catalyst, whereas linear sweep voltammetry results showed that this material is characterized by high current response. The direction of electron migration in the p-n type heterojunction (p-FeLaO 3 /n-CoS 2 ) was found to be the same as that of photoexcited electron transfer (from the conduction band of CoS 2 to the valence band of FeLaO 3 ), which enhances the photocatalytic hydrogen evolution activity of the composite material. This work provides a feasible and simple strategy for the design and synthesis of FeLaO 3 -doped composite catalysts with high photocatalytic activity.
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ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Pengcheng Du,Yuman Dong,Hongxing Kang,Qi Wang,Jingye Niu
p-Phenylene diamine (PPD) was selected as functional monomer to modify the holey graphene networks (rHGO-PPD) by a facile one-step hydrothermal method . rHGO-PPD was employed as promising active electrode materials to apply in supercapacitors (SCs), which exhibited excellent electrochemical performance, including high specific capacitance (375.5 F/g at current density of 0.5 A/g), excellent rate capability and good cycling stability due to the contribute of pseudocapacitive behavior of PPD. For further pursuit of great value in the practical application, the rHGO-PPD was used to fabricate symmetric SCs and flexible solid-state SCs (FSSCs). The FSSCs possessed high specific capacitance of 332.4 F/g, maintained good cycling stability of 74% of its initial capacitance up to 5000 charge-discharge cycles. In addition, FSSCs also exhibited extraordinary mechanical flexibility, and also maintained excellent stability even in a harsh environment. Remarkably, the FSSCs showed excellent long-term storage stability, and the capacitance kept about 88% after ten weeks of storage. Therefore, the FSSCs based on rHGO-PPD electrode material display promising application in flexible energy-storage devices.
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Polymers
·
2019
·Vol. 11
·期 8
·1231
·
IF 3.164
Xuan Yang,Qunzhang Tu,Xinmin Shen,Qin Yin,Ming Pan,Chengming Jiang,Caibing Hu
To enhance the interfacial adhesion between poly(p-phenylene terephthalamide) (PPTA) fibers and a rubber matrix without damaging the fiber structures, aminated carbon nanotubes (NH2-CNTs) were mildly deposited onto the fiber surface by combining the biomimetic modification of dopamine via the Michael addition reaction. Furthermore, differences between the “one-step” method and the “two-step” method were researched through adjusting the addition sequence of NH2-CNTs. The surface morphologies and chemical structures of PPTA fibers before and after modification were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The mechanical properties of fibers and the adhesive properties with rubber were tested using an electronic tensile tester of single-filament and universal testing machine, respectively. After modification by the “one-step” method for 24 h, the single-filament tensile strength of the modified fibers increased by 16.5%, meanwhile, the pull-out force of the modified fibers to rubber increased by approximately 59.7%. Compared with the “two-step” method, the “one-step” method had superiority due to the short reaction time and the large deposition rate of CNTs.Keywords:poly(p-phenylene terephthalamide) fibers;dopamine biomimetic modification;aminated carbon nanotubes;interfacial adhesion
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