CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xiaomeng Yang,Zhen Zhang,Puhua Shao,Armin Rezayan,Dan Wu,Chunbao Charles Xu,Jianshe Wang,Yongsheng Zhang
Selective hydrogenolysis of 4-O-5 bond in lignin under relatively mild conditions is an important strategy for the production of valuable aromatic products, e.g. phenols, from renewable carbon resources. However, the easy saturation of benzene rings under reductive conditions over metal catalyst reduces the selectivity to aromatics. In this work, we investigated the effect of bromination of supported Ni nanoparticles on the phenol selectivity during the hydrogenolysis of diphenyl ether (DPE), a commonly used lignin model compound. Compared with the unmodified catalysts, Br-Ni/Al 2 O 3 catalyst derived from Ni-Al layered double oxides exhibits enhanced phenol selectivity (37% vs. 15%) under similar DPE conversions (60%). Various characterizations including transmission electron microscopy (TEM), in-situ X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), and CO-Fourier transform infrared spectroscopy (FTIR) indicate that Br preferentially located at the terrace site of Ni nanoparticles, deactivating the continuous Ni sites for benzene ring hydrogenation. In addition, the electron-withdrawing effect of Br creates positively charged Ni sites at the corners, facilitating the hydrogenolysis of C–O aryl ether bonds. During the hydrogenation of real lignin, the selective poisoning and electronic effects introduced by Br synergistically increased the yield of phenols from 12.20% on the initial Ni/Al 2 O 3 to 30.47% over the Br-Ni/Al 2 O 3 catalyst. This work provides an advanced strategy for the catalytic valorization of lignin by halogen modified metal-based catalysts.
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Journal of Materials Research and Technology-JMR&T
·
2021
·
IF 5.039
Weiwei Zhang,Tianyong Mei,Baosong Li,Lu Yang,Shengsong Du,Yicheng Miao,Hongqiang Chu
In this work, Ni/diamond composite coatings have been synthesized by electrodeposition in direct current mode. The effects of mechanical and ultrasonic agitations on the microstructural, surface characteristics and electrochemical properties have been comparatively investigated by various methods. Results show that diamond nanoparticles have been evenly dispersed in Ni metallic matrix, which could reinforce their performances. The coatings prepared under ultrasonic and mechanical agitation both exhibit compact, dense and hill-valley like morphology with pyramid-like nickel crystallite grains. The relative texture coefficient (RTC) values show that the preferred orientation of the Ni/diamond coating was (200) texture. From 3 to 5 A dm −2 , the crystallite sizes of ultrasonic conditions were 59.2–81.7 nm, which were smaller than 76.3–83.2 nm of magnetic agitations. The average roughness ( R a = 78.9–133 nm) of ultrasonic-assisted coatings were lower than 103–139 nm of magnetic conditions. The mechanism of the co-electrodeposition process was proposed. Electrochemical impedance spectroscopy (EIS) results illustrate that the ultrasonic-assisted electrodeposited Ni/diamond coating has better corrosion resistance than that prepared under mechanical stirring conditions. The Ni/diamond composite coatings could be applied as protective materials in harsh mediums.
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JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2021
·Vol. 168
·期 3
·034516
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IF 4.316
Kai Li,Yafeng Jin,Wenming Gao,Shoucai Xue,Ming Zhang
A critical issue for massive production of metal-supported solid oxide fuel cell is cathode processing due to the contradicting of the metal support and the cathode with regard to the sintering atmosphere. Herein, LSM-BSCF (La0.8Sr0.2MnO3-δ coated Ba0.5Sr0.5Co0.8Fe0.2O3-δ) cathodes on Ni-Fe alloys supported SOFCs (NF-SOFCs) are fabricated by an ex situ sintering approach and electrochemical evaluation in humidified H2 fuel. The ex situ sintering of cathodes on NF-SOFCs are performed at 1050 °C in air with metal oxide support consisted of NiO and 10 at% Fe2O3, and then the oxide support is reduced in situ into Ni-Fe alloys during testing. Cross-section microstructure analysis shows clear evidence that each layer is well adhered to each other after reduction and the suitable microstructure of ex situ sintered cathode is observed after sintering at 1050 °C. In the single-cell test, a higher peak power density is achieved for NF-SOFC with ex situ sintered LSM-BSCF in comparison with in situ sintered cells, revealing a beneficial effect of ex situ sintered cathode on cell performance. The durability measurement and post-test analysis confirm the sufficient adherence and mechanical stability between ex situ sintered LSM-BSCF cathode and GDC (Ce0.9Gd0.1O1.95) electrolyte. The successful electrochemical characterizations of NF-SOFCs with ex situ sintered LSM-BSCF cathode confirm the applicability of the novel sintering procedure.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jingwen Zhang,Chuchu Cheng,FangShu Xing,Cheng Chen,Caijin Huang
Engineering semiconductor materials with vacancies and co-catalysts is a valid method to improve their photocatalytic performance. Herein, we prepared S vacancies-rich Mn 0.3 Cd 0.7 S nanorods modified with β-Ni(OH) 2 nanoparticles through solvothermal and co-precipitation strategies. The as-obtained 0D/1D β-Ni(OH) 2 /Mn 0.3 Cd 0.7 S nanorods exhibit excellent visible-light H 2 -production activity up to 71.09 mmol g −1 h −1 , 5.23 times higher than pure Mn 0.3 Cd 0.7 S and better than 1 wt% Pt/Mn 0.3 Cd 0.7 S and most reported Mn x Cd 1−x S-based catalysts. The apparent quantum yield reaches 46.68% at λ = 420 nm. We found that the presence of S vacancies and β-Ni(OH) 2 enhances the transfer/separation of photogenerated carriers and increases reaction sites, which is beneficial to photocatalytic H 2 -production reaction. This work proposes a new idea for the application of metal hydroxide co-catalysts and S vacancies in sulfide materials for photocatalytic H 2 production.
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Nanoscale
·
2021
·Vol. 13
·期 42
·17953-17960
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IF 7.79
Yuanyuan Wu,Junqiang Yin,Wei Jiang,Hongji Li,Chunbo Liu,Guangbo Che
Developing efficient and promising non-noble catalysts that can promote both the HER and OER in the same electrolyte is vital. Currently, these reported bifunctional catalysts show only moderate electrocatalytic water-splitting performance, which is much lower than expected. In addition, most of these promising nonprecious electrocatalysts work well only at small current densities (e.g. 10 mA cm−1), but at large current densities their stability and activity are far from satisfactory for practical applications. Herein, we have successfully constructed an urchin-like Ni3S2@Ni3B heterostructure electrocatalyst on Ni plates. The resulting material exhibits great catalytic activities for both the HER and OER, even at large current densities, reaching a current density of 1000 mA cm−l at relatively low applied overpotentials of 517 and 632 mV, respectively. The excellent catalytic performance of Ni3S2@Ni3B/NP is found to benefit from the effective integration of the unique surface structure and the interface electronic structure.
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PubMed
高影响因子
Processes
·
2021
·Vol. 9
·期 10
·1718
·
IF 2.847
Pan Luo,Song Lyu,Bowen Zhang,Hui Wang,Yanping Zhou,Bing Zhang,Kama Huang
As the problems of electromagnetic pollution and interference are becoming increasingly serious, the development of electromagnetic absorption materials with a high absorption capacity and broad absorption bandwidth are stringently needed. In this work, an N-doped 2D carbon/Ni complex is synthesized through direct microwave irradiation on a mixed solution of nickel nitrate, urea, and agarose under N2. The electromagnetic absorption performance can be tuned by controlling the Ni content. Specifically, minimum reflection loss values (RLmin) of −65.5 dB at 15.8 GHz with an effective absorption bandwidth (EAB) of 4.2 GHz at a sample thickness of 1.47 mm, and −55.4 dB at 11.8 GHz with an EAB of 3 GHz at a sample thickness of 1.92 mm can be obtained. The outstanding performance of electromagnetic absorption is attributed to the multiple polarization relaxation processes and the synergistic effect between 2D carbon sheets and Ni particles.Keywords:microwave assisted synthesis;electromagnetic absorption;2D carbon;nitrogen doping
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ACS Catalysis
·
2021
·
IF 13.084
Ting Wang,Yuebing Xu,Yufeng Li,Lei Xin,Bing Liu,Feng Jiang,Xiaohao Liu
Conversion of syngas into aromatics via the Fischer–Tropsch (FT) route provides a promising way to supply the value-added chemicals. However, it is still a great challenge to achieve controllable aromatics selectivity with good stability. Herein, we report the Na-mediated bimetallic Fe–Ni catalyst simply particle mixed with HZSM-5, which can boost the stable and selective production of aromatics from the syngas. In detail, FeNiOx(5:1)-0.41Na exhibits quite stable catalytic activity with notably higher selectivity to light α-olefins (C2=–C4=) compared to α-Fe2O3-0.75Na. Various characterizations suggest that an appropriate addition of Ni with Na substantially regulates iron carbide formation and suppresses carbon deposition owing to the electron donation of Fe to Ni reducing CO adsorption and dissociation. Interestingly, extra Na results in remarkably increased selectivity to C1o–C4o, despite the fact that Na shows the ability to suppress hydrogenation. Both characterizations and density functional theory (DFT) calculations demonstrate that the addition of Na weakens the Fe–Ni interaction and reduces electron transfer from Fe to Ni, which promotes C1o–C4o formation as Ni tends to reflect its intrinsic catalysis. DFT calculations confirm that the adsorbed CH2 species at the Ni–Fe interface prefers to undergo coupling to form C2H4, and the formed C2H4 spontaneously desorbs from the surface, indicating that the formation of lower olefins is favorable and further chain growth is inhibited. This could be attributed to the fact that the accumulated electron at the Ni–Fe interface weakens the binding strength of CH2 and C2H4 species because of electronic repulsion. Furthermore, the effects of FT product distribution on aromatics formation were also investigated. FeMnOx(5:1)-0.40Na produces longer olefin-rich hydrocarbons in C5+ owing to oxygen vacancy-assisted CO dissociation, leading to highly branched monocyclic aromatics and faster HZSM-5 deactivation because of increased coking from the isomerization–hydrocracking of long hydrocarbons. In contrast, FeNiOx(5:1)-0.41Na-HZSM-5 produces major light aromatics about 65.7% including toluene, ethyl-benzene, and xylene in total aromatics with about 98.6% aromatics in the liquid phase, which benefits from the fact that FeNiOx(5:1)-0.41Na makes shorter hydrocarbons in C5+ and/or Ni metal has a strong ability of H2 dissociation to provide atomic H spillover onto HZSM-5. Thus, HZSM-5 also shows improved stability. Note that the mixed catalysts with a high Na content indicate a substantial Na+ migration to increase light α-olefins in the gas phase owing to suppress H-transfer reaction. This study provides deep insights into how to develop stable and selective iron-based catalysts for the production of FT products and its further conversion into value-added light aromatics.
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JOURNAL OF THE ENERGY INSTITUTE
·
2021
·
IF 6.186
Yunwu Zheng,Jida Wang,Donghua Li,Can Liu,Yi Lu,Xu Lin,Zhifeng Zheng
To improve the quality of bio-oil and minimize coke formation, ex-situ catalytic biomass pyrolysis vapor upgrading to high-grade bio-aromatic and phenol compounds with Py-GC × GC/MS at different nickel-to-copper ratios was investigated. At the same time, the deoxygenation efficiency, structure-activity relationship, deactivation mechanism and possible pathways between combined mono- and bimetallic catalysts were also demonstrated. Ni and Cu species could be well dispersed, and the HZSM-5 support maintained the MFI crystal structure after bimetallic Ni–Cu modification, but the surface area, pore volume, and total acidity decreased. Bimetallic Ni–Cu catalysts showed better deoxygenation efficiency than monometallic catalysts, which had more advantages in the preparation of aliphatic hydrocarbons (29.86%) than mono- and bimetallic catalysts, which favored the production of aromatics (28.89%). Higher-Ni-loading catalysts promoted the formation of aliphatic hydrocarbons, aromatics and alkanes due to decarboxylation, decarbonylation and aromatization reactions, and higher-Cu-loading catalysts enhanced the olefin and phenol yields due to dehydration and demethylation reactions. Overall, the highest yields of bio-aromatic compounds and phenols were46.78% and 36.34%, respectively, at Ni-to-Cu ratios of 1:1 and 1:2, due to the high total acid amount and suitable average pore size for bio-aromatics and the low acidity and large pore size for phenols. The bimetallic Ni–Cu catalyst significantly increased the quality of bio-oil and reduced coke deposition.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Zhenlin Ma,Rong Zheng,Yu Liu,Yulong Ying,Weidong Shi
Recently, carbon nanotubes (CNT)-based interconnected architectures exhibit promising prospects in supercapacitors due to their flexibility and high electrical conductivity. Herein, a three-dimensional (3D) interconnected network structure combined with conductive carbon nanotubes interpenetrating MOFs-derived Co-Ni-S composite spheres (Co-Ni-S/CNTs) was synthesized. Such 3D interconnected architecture significantly leads to a favorable electronic structure, fast charge-transfer capacity, and more pseudocapacitive. The Co-Ni-S/CNTs-based hybrid electrode exhibits an extraordinary specific capacitance of 540.6C g −1 at 1 A g −1 and competitive rate performance (capacity retention rate of 69.9% when the current density increases to 10 times). Subsequently, a hybrid supercapacitor is assembled using Co-Ni-S/CNTs as the positive electrode and commercial activated carbon as negative electrode. The device delivers a high energy density of 63.5 W h kg −1 at 800 W kg −1 and keeps 83.0% initial capacitance retention after 10,000 cycles. The encouraging performances demonstrate the significant contribution of the 3D interconnected architecture for the future energy storage.
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PubMed
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Xiaorui Zhang,Yu Mei,Hao Cheng,Jianfeng Ma,Fang Zhu,Sridhar Komarneni
NiO and CeO 2 composite metal oxides (NiO–CeO 2 ) were synthesized by sol-gel method to investigate a degradation system by persulfate (PS) activation with the assistance of visible light (Vis). The phase composition of NiO–CeO 2 was detected by X-ray diffraction (XRD), the morphology of NiO–CeO 2 was characterized by scanning electron microscope (SEM), and the result of X-ray photoelectron spectroscopy (XPS) proved the element composition and valence state of the NiO–CeO 2 . In the Vis/PS/NiO–CeO 2 system, the degradation rate of Orange II using a concentration of 50 mg/L was as high as 90% in 15 min but it increased to as high as 99% in 60 min. Mechanism studies have shown that the combination of NiO and CeO 2 generated more oxygen vacancies , and activated persulfate to generate active oxygen species. Moreover, the effects of visible light , persulfate concentration and pH were evaluated, and the results showed that the participation of visible light and persulfate could significantly increase the degradation efficiency of Orange II, but pH had little effect on the degradation. Quenching experiments and detection by ESR showed that O 2 ‾, •SO 4 ‾, •OH, and 1 O 2 all contribute to the removal of Orange II. In addition, the recovery and reuse properties of NiO–CeO 2 may lead to sustainable treatment of wastewater.
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FUEL
·
2020
·
IF 5.578
Muhammad Irfan,Aimin Li,Lei Zhang,Guozhao Ji,Yuan Gao
Catalytic gasification, coupled with in-situ CO 2 capture over Ni-CaO catalyst, is considered to be an effective approach for H 2 -rich and tar-free syngas production. However, the poor stability of Ni-CaO based catalyst raises a question regarding its large scale application. In this study, HfO 2 was used as a stabilizer and promoter for the Ni-CaO catalyst system. The stability of catalyst was evaluated through cyclic carbonation-calcination test with a thermogravimetric analyzer. The results showed that HfO 2 incorporated catalysts performed better stability towards cyclic CO 2 capture. The effect of different HfO 2 additions in catalyst, catalyst to municipal solid waste (C/MSW) ratio, gasification temperature, and moisture content (MC) of MSW was investigated on syngas composition, H 2 yield, dry gas yield (DGY) and product distribution (syngas, tar and char). The results indicated that H 2 yield was improved from 212 mL/g (without catalyst) to 442 mL/g with Ni-CaO (NC) catalyst and further improved with the application of HfO 2 promoted catalysts (Ni-CaO-HfO 2 ). The catalyst with 20% HfO 2 (NCH-20) exhibited maximum H 2 yield of 597 mL/g. Moreover, a significant reduction in tar content from 8.79 wt% (without catalyst), 3.19 wt% (with Ni-CaO) to 2.81 wt% (with NCH-20) was also recorded with HfO 2 promoted catalysts.
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CATALYSIS LETTERS
·
2020
·Vol. 151
·期 2
·538-547
·
IF 2.482
Chen Han,Xu Qiong,Li Hui,Liu Jian,Liu Xianxiang,Huang Geng,Yin Dulin
Nickel supported on equilibrium fluid-catalytic-cracking catalysts (Ni/E-cats) were prepared by a simple grinding-pyrolysis method and employed for the transfer hydrogenation of ethyl levulinate (EL) to γ-valerolactone (GVL). 96.2% selectivity of GVL and 90.3% conversion of EL were obtained at 180 °C for 6 h over 30-Ni/E-cat. Through XRD, N 2 adsorption–desorption, NH 3 -TPD and SEM analysis, the high activity of the 30-Ni/E-cat catalyst was attributed to its dispersed Ni metal active centers and available acidic sites. Catalytic probe test revealed that metal and acid sites of Ni/E-cat played a synergistic catalytic role in the synthesis of GVL in 2-propanol, where Ni metal sites contribute to the hydrogenation of ketone group in EL, and acid sites of E-cat promoted the lactonization of intermediate ethyl- or isopropyl 4-hydroxyvalerate. Two reaction pathways and synergistic mechanism were proposed in this catalytic system. Moreover, Ni/E-cat catalyst exhibited good stability up to four cycles without obvious loss of catalytic activity. Graphic Abstract
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危险品化学品经营许可证（带存储）