Catalysis Science & Technology
·
2023
·Vol. 13
·期 13
·3974-3986
·
IF 5
Meng Xia,Zheng Shen,Shaoze Xiao,Minyan Gu,Yalei Zhang
During the catalytic transformation of biomass into valuable chemicals, enhancing the yield of target products and inhibiting undesirable reactions are vital but challenging. In this study, a facile and efficient method for synthesizing a hierarchical bimetallic Mg–Sn-Beta-H zeolite was developed. Using this method, the simultaneous fabrication of catalytically active sites and hierarchical structures was achieved. Selective experiments and kinetic analysis confirmed that the catalytically active sites and hierarchical structures in the catalyst exhibited a clear synergistic effect on the transformation of glucose into lactic acid with a high yield of 62.7%, and the lactic acid yield remained above 58% after reusing the catalyst four times. An in-depth analysis of the synergistic catalysis mechanism demonstrated that strong and weak Lewis acidity in the catalytically active sites promoted the main reaction steps, including isomerisation and retro-aldol condensation, whereas the hierarchical structure induced by the introduction of magnesium into the parent Sn-Beta zeolite regulated the main reaction steps and suppressed the side reactions. The coupling of multifunctional active sites and hierarchical structures provides a new strategy for addressing the challenges of commercial lactic acid production.
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Qifeng Yang,Yiming Mo
Selective oxidation of high-energy C–H bonds to produce carbonyl compounds is a fundamental transformation in fine chemical synthesis. Despite tremendous efforts, the development of green and safe strategies often suffers from harsh reaction conditions and uses homogeneous transition-metal catalysts. Herein, we present an electrochemical oxidation strategy that is green and safe for the direct oxidation of benzylic C–H bonds using La2O3 nanoparticles supported on a carbon paper (La2O3/CP) anode. La2O3/CP can selectively oxidize indane to indanone in 83% yield with 73% Faraday efficiency at room temperature. It also can oxidize different kinds of compounds with benzyl C–H bonds to produce the corresponding ketones with moderate-to-excellent yields. The oxygen source was confirmed to be water by an oxygen isotope (18O) tracer experiment. Additionally, the La2O3@C/CP composite electrode was reconfigured through carbonizing oleic acid to stabilize La2O3 on CP, resulting in an improved stability due to the reinforced catalyst embedding on CP, and retaining 81% initial activity after five cycles.
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Lei Zhuang,Mingyuan Jian,Ruifang Xue,Nan Li,Jie Chen,Yanghe Fu,De–Li Chen,Weidong Zhu,Fumin Zhang
Developing efficient heterogeneous catalysts for the aerobic oxidation of C–H bonds using oxygen molecule as an oxidant to produce value–added aryl ketones is a challenging task. In this study, a series of cementite–iron–carbon composites (referred to as Fe–C–T, where T represents the pyrolysis temperature) were synthesized using a metal–organic–framework–mediated sacrificial template strategy. The Fe–C–T composites consist of highly dispersed Fe/(Fe 3 C or Fe 2 O 3 ) nanoparticles surrounded by graphitic carbon on porous carbon supports. Under mild reaction conditions (1 atm of O 2 pressure, 353 K, 12 h), with tert–butyl hydroperoxide (0.25 equiv.) as the initiator in a green solvent water, the prepared Fe–C–973 achieved a high conversion of 98.4 % for ethylbenzene and a selectivity of 98.7 % for acetophenone . This performance was markedly superior to the comparable Fe–C–873 and Fe–C–1073, as well as the commercially available Fe–based catalysts. Kinetic studies revealed that the catalytic system followed first–order kinetics for the substrate ethylbenzene, and the activation energy over Fe–C–973 was remarkably low of 40.4 kJ/mol. The highly distributed Fe 3 C nanoparticles embedded in the porous carbon framework were identified as the most active sites for the reaction.
✓ 已验证
产品关联
DOI
高影响因子
BIOMATERIALS
·
2021
·
IF 12.479
Yang Tian,Wen-Li Jiang,Wen-Xin Wang,Guo-Jiang Mao,Yongfei Li,Chun-Yan Li
The reduced coenzymes (NADH and NADPH) are an important product in energy metabolism and closely related to the occurrence and development of cancer. So it is necessary to use a powerful detection tool to visualize NAD(P)H in energy metabolism of tumor cells and find a new strategy to improve cancer treatment based on NAD(P)H. Herein, a novel multifunctional probe (Cy-N) is synthesized with good near-infrared fluorescence (NIRF) response to NAD(P)H and the photoacoustic (PA) and photothermal properties are successfully activated by NAD(P)H. The probe is successfully applied in visualizing NAD(P)H in energy metabolism of tumor cells and imaging NAD(P)H in bacteria. Moreover, the probe can be used to image NAD(P)H in energy metabolism of tumor-bearing mice by dual-modal imaging (NIRF and PA). More importantly, in terms of the role of NAD(P)H in energy metabolism, the photothermal therapy (PTT) is activated by NAD(P)H and a novel strategy of enhanced PTT is proposed by injecting glucose. As far as we know, this is the first probe to detect NAD(P)H in energy metabolism through dual-modal imaging, and also the first probe to activate PTT based on NAD(P)H, which will provide important information of the diagnosis and treatment of cancer.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2020
·
IF 5.778
Jiuhu Zhao,Gaige Zhang,Jiansheng He,Zhengzhong Wen,Zhi Li,Tingkun Gu,Ran Ding,Yongji Zhu,Rongshu Zhu
In/H-Beta catalyst was prepared by optimizing the support, concentration of ion exchange liquid and calcination temperature to investigate the effects of synthesis conditions on catalytic activity of selective catalytic reduction of NO x with CH 4 . The results showed that the In/H-Beta catalyst exhibited the superior activity when concentration of exchange liquid was 0.033 M and calcination temperature was 500 °C, the NO x removal ratio could reach 97.6%. In addition, reaction conditions could affect the catalytic performance. When O 2 concentration was 10%, CH 4 :NO ratio was no less than one, space velocity was lower than 23600 h −1 and NO initial concentration was no more than 700 ppm, In/H-Beta could exhibit superior catalytic activity. Moreover, the catalytic performances of In/H-Beta catalysts were discussed after enduring H 2 O or/and SO 2 . This novel strategy could open the door for selective catalytic reduction of NO x with CH 4 .
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS LETTERS
·
2021
·Vol. 152
·期 4
·1145-1159
·
IF 3.186
Yu Guiyun,Zhao Yefan,Zhang Yulong,Wu Jiaxin,Liu Chao
There are increasing concerns of environmental-pollution and energy issues. Herein, an exfoliation-restacking process was firstly employed to synthesize H + -restacked H + Ti 2 NbO 7 − nanosheets (HTNS), and then heated with melamine at 510 °C to obtain direct Z-scheme layered N-doped H + Ti 2 NbO 7 − /g-C 3 N 4 (TCN) heterojunctions with an increased specific surface area. Two-dimensional (2D) g-C 3 N 4 material was in-situ formed on the surface of HTNS to achieve a layered heterostructure between two components, which could maximize interfacial contact area and minimize interfacial distance for the efficient charge carrier separation. Simultaneously, the surface of HTNS was doped by nitrogen atoms to form visible-light-responsive N-doped HTNS. All TCN x ( x = 1, 2 and 3) composites exhibited the enhanced photocatalytic activity for both hydrogen (H 2 ) production and rhodamine B (RhB) degradation. As an optimal sample, the resulted TCN2 composite exhibited the best photocatalytic efficiency for H 2 production and RhB degradation. The enhanced photocatalytic activity was assigned to the combined effects of layered heterojunction, N-doping and large specific surface area. According to trapping experiments and electron spin resonance (ESR) spectra, the holes (h + ), superoxide (·O 2 − ) and hydroxyl (·OH) radicals were responsible for photocatalytic RhB degradation and especially the ·O 2 − was the key active specie. A possible charge transfer pathway was analyzed in detail. This work will hopefully provide some guidance on designing Z-scheme layered heterojunction photocatalyst systems with highly photocatalytic efficiency. Graphical Abstract Direct Z-scheme layered N-doped H + Ti 2 NbO 7 − /g-C 3 N 4 heterojunction photocatalysts were constructed by a three-step exfoliation-restacking-calcination process, showing the highly photocatalytic efficiency for H 2 production and RhB degradation under visible light due to the synergistic effects of layered heterojunction, N-doping and large specific surface area.
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2018
·Vol. 8
·期 8
·326
·
IF 3.465
Peng Sun,Jun Zhang,Wenxiu Liu,Qi Wang,Wenbin Cao
In this paper, the Langmuir-Hinshelwood (L-H) model has been used to investigate the kinetics of photodegradation of gaseous benzene by nitrogen-doped TiO2(N-TiO2) at 25 °C under visible light irradiation. Experimental results show that the photoreaction coefficientkpmincreased from 3.992 × 10−6mol·kg−1·s−1to 11.55 × 10−6mol·kg−1·s−1along with increasing illumination intensity. However, the adsorption equilibrium constantKLdecreased from 1139 to 597 m3·mol−1when the illumination intensity increased from 36.7 × 104lx to 75.1 × 104lx, whereas it was 2761 m3·mol−1in the absence of light. This is contrary to the fact thatKLshould be a constant if the temperature was fixed. This phenomenon can be attributed to the breaking of the adsorption-desorption equilibrium by photocatalytically decomposition. To compensate for the disequilibrium of the adsorption-desorption process, photoreaction coefficientkpmwas introduced to the expression ofKLand the compensation form was denoted asKm.KLis an indicator of the adsorption capacity of TiO2whileKmis only an indicator of the coverage ratio of TiO2surface. The modified L-H model has been experimentally verified so it is expected to be used to predict the kinetics of the photocatalytic degradation of gaseous benzene.Keywords:modified L-H model;N-TiO2;photocatalytic degradation;benzene
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Lei Wang,Xin Zhang,Yonggang Sun,Yulong Ma,Min Xu,Juan Zhang,Yingbo Zhu,Li Zhu,Song Qiao,Jing Ma,Jinpeng Wei,Feng Lin
Environmental H 2 O has a significant effect on the reaction mechanism and process of VOC oxidation, of which the intrinsic mechanism is hardly reported. Herein, a series of PtCu δ -MnO x catalysts with different strong metal-supported interactions were constructed by replacing some Pt species with Cu species. Among them, the PtCu 3 -MnO x catalyst exhibited superior catalytic performance (T 90 = 170 ℃), high water resistance, and long-term stability. Furthermore, in-situ diffuse reflectance infrared Fourier transform spectroscopy ( in-situ DRIFTs) showed that the acetone oxidation followed synergistic cooperation of the Langmuir-Hinshelwood (L-H) and Mars van Krevelen (MvK) mechanism. Acetone oxidation over PtCu 3 -MnO x occurred via the L-H mechanism producing surface acetate and formate species intermediate. Above 100 °C, adsorbed acetone (i.e., acetate and formate species) reacts with MnO x lattice oxygen according to the MvK mechanism to form CO 2 and H 2 O. When water vapor was present, the L-H mechanism was impaired, inhibiting the deep oxidation of acetone. This research provides an in-depth exploration of how water vapor impacts the reaction mechanism of acetone oxidation. It offers valuable insights for creating dependable catalysts suitable for use in various industrial settings.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Fangxian Wang,Junwei Yang,Shihao Li,Junwen Liang,Yuwei Wang,Rong Du,Bo Zhou,Qiong Liu,Changping Li
Bromate is a commonly identified carcinogenic and genotoxic disinfection byproduct in water. Electrochemical debromination is an environmentally friendly and effective approach but it often suffers the limited reducing atomic H (H*) ability and high metal catalyst dosage. In this study, a unique composite catalyst comprised of ultra-low loading Cu single atoms (0.016 wt%) and Fe 2 O 3 nanoparticles supported on a Nb 2 C MXene (denoted as Cu 0.2 /Fe 0.1 /Nb 2 C) was synthesized by one-step high-temperature molten salt method. The Cu 0.2 /Fe 0.1 /Nb 2 C significantly outperformed the Nb 2 C, Cu 0.2 /Nb 2 C and Fe 0.1 /Nb 2 C counterparts in the electrochemical debromination with a 94.2 % removal efficiency of bromate. It is revealed that the introducing of Cu single atoms, efficiently promotes the adsorption of H* and inhibition of competitive H 2 evolution. The incorporation of Fe 2 O 3 nanoparticles significantly increased the electronic metal-support interaction effect between the metal components and Nb 2 C, thereby forming a noticeable electronic cloud bridge to facilitate efficient charge transfer. Ultimately, the synergistic interplay between Cu single atoms and Fe 2 O 3 nanoparticles plays a crucial role in achieving the remarkable removal performance of bromate. This work not only presents a significant instance of a synergistic catalyst involving metal single atoms and metal nanoparticles for effective electrochemical debromination but also advances the understanding of the electronic metal-support interaction.
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 16
·3747
·
IF 4.2
Guanyu Chen,Weixin Zhang,Rongshu Zhu,Yanpeng Chen,Minghu Zhao,Mei Hong
Zeolite-based catalysts efficiently catalyze the selective catalytic reduction of NOxwith methane (CH4-SCR) for the environmentally friendly removal of nitrogen oxides, but suffer severe deactivation in high-temperature SO2- and H2O-containing flue gas. In this work, SSZ-39 zeolite (AEI topology) with high hydrothermal stability is reported for preparing CH4-SCR catalysts. Mild acid leaching with oxalic acid (OA) not only modulates the Si/Al ratio of commercial SSZ-39 to a suitable value, but also removes some extra-framework Al atoms, introducing a small number of mesopores into the zeolite that alleviate diffusion limitation. Additional Co3O4modification during indium exchange further enhances the catalytic activity of the resulting In-Co3O4/H-SSZ-39(OA). The optimized sample exhibits remarkable performance in CH4-SCR under a gas hourly space velocity (GHSV) of 24,000 h−1and in the presence of 5 vol% H2O. Even under harsh SO2- and H2O-containing high-temperature conditions, it shows satisfactory stability. Catalysts containing Co3O4components demonstrate much higher CH4conversion. The strong mutual interaction between Co3O4and Brønsted acid sites, confirmed by the temperature-programmed desorption of NO (NO-TPD), enables more stable NxOyspecies to be retained in In-Co3O4/H-SSZ-39(OA) to supply further reactions at high temperatures.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2017
·Vol. 23
·期 41
·9831-9837
·
IF 5.317
Qiang Cao,Qing Yin,Qi Chen,Zhi-Bing Dong,Bao-Hang Han
Graphical Removed from the mix : The synthesis of fluorinated iron–porphyrin conjugated porous polymers through direct C−H arylation polymerization is described (see scheme). The application of these polymers as heterogeneous catalysts for Baeyer–Villiger oxidation is also discussed. By considering the high reactivity of fluorinated iron–porphyrin and good stability of porphyrin-based porous polymers, fluorinated iron–porphyrin conjugated porous polymers ( FPOP-3 – 6 ) were synthesized through direct C−H arylation polymerization. The obtained materials are chemically and thermally stable, of which FPOP-3 exhibits the highest Brunauer–Emmett–Teller specific surface area (about 840 m 2 g −1 ). For functional studies of the obtained polymers as heterogeneous catalysts, catalytic transformation of cycloketones into lactones by oxygen through Baeyer–Villiger oxidation was used as a model reaction. Fluorinated phenyl substituents of the iron–porphyrin not only are beneficial to the conversion, but also can stabilize the porphyrin to resist catalyst breakdown. The polymer FPOP-3 , with high porosity, exhibits the best catalytic efficiency and recycling effect. The recovered catalyst also shows good catalytic activities after recycling three times with a small loss in yield.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Guangpeng He,Deyu Kong,Xiaoguang Chen,Shujing Fan,Tao Meng,Jiabin Li
In this paper, low-cost dihydrate gypsum (CaSO 4 ⋅2H 2 O) was used as calcium source together with sodium metasilicate solution to prepare calcium silicate hydrate (C-S-H) gels through a mechanochemical activation strategy by using planetary and vibrational ball-milling. The influences of the prepared C-S-H gels on hydrating and hardening properties of super-retarded cement-based materials with sucrose were investigated. The results showed that CaSO 4 ⋅2H 2 O reacted with sodium metasilicate solution under mechanochemical effect during both planetary and vibrational ball-milling, although CaSO 4 ⋅2H 2 O was just slightly dissolved in water. It was also interestingly found that the C-S-H gels can continuously form while resting for a certain time after ball-milling. Under the mechanochemical activation, the prepared C-S-H gels had complete characteristic diffusion peaks and were composed of layered, flocculent and fibrous structures. While incorporating the prepared C-S-H gels into the super-retarded cement paste with sucrose, the cement hydration was greatly accelerated and the compressive strength of the hardened cement-based materials was also effectively improved at early age as expected. Through X-ray diffraction (XRD) analysis, it was found that C-S-H gels can effectively promote the growth of CH crystals along the (001) and (101) crystal planes. The scanning electron microscopy (SEM) results supported that the C-S-H gels inhibited the refinement of ettringite (AFt) crystals in super-retarded HCP with sucrose, which was more obvious at 28 d.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）