The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts c...The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.展开更多
This paper lays particular emphasis on pun's effectiveness and selectivity in English advertisements.The illustration and examples can help us understand the English advertisements well and foster our ability to a...This paper lays particular emphasis on pun's effectiveness and selectivity in English advertisements.The illustration and examples can help us understand the English advertisements well and foster our ability to appreciate the charm of English.展开更多
The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was exami...The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.展开更多
The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficien...The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficiency is limited by(bi)carbonates formation.Acidic media have emerged as a solution,addressing the(bi)carbonates challenge but introducing the issue of the hydrogen evolu-tion reaction(HER),which reduces CO_(2) conversion efficiency in acidic environments.This review focuses on enhancing the selectivity of acidic CO_(2) electrolysis.It commences with an overview of the latest advancements in acidic CO_(2) electrolysis,focusing on product selectivity and electrocatalytic activity enhancements.It then delves into the critical factors shaping selectivity in acidic CO_(2) electrolysis,with a special emphasis on the influence of cations and catalyst design.Finally,the research challenges and personal perspectives of acidic CO_(2) electrolysis are suggested.展开更多
Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but ful...Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3).展开更多
Understanding the synergistic effect between ligands at the atomic level to control the catalytic selectivity of catalysts remains a significant challenge due to the complexity of ligand interactions and limitations i...Understanding the synergistic effect between ligands at the atomic level to control the catalytic selectivity of catalysts remains a significant challenge due to the complexity of ligand interactions and limitations in current analytical techniques.Herein,using precisely structured metal nanoclusters as models,we discovered that altering the electronegativity of substituents on donor thiolate ligands can modulate the bond dissociation energy of coordinated phosphine ligands on the clusters.This change leads to the selective dissociation of ligands during the catalytic process,thereby enabling control over catalytic selectivity with an abrupt increase in formate production from~0%to 23%.This work provides crucial insights into understanding ligand interactions on metal nanoparticle surfaces at the atomic level and lays the foundation for designing highly selective catalysts in the future.展开更多
The tensile behavior of(Fe_(50)Mn_(30)Co_(10)Cr_(10))_(100-x)Si_(x)(x=0(Si0),2(Si2))metastable HEAs prepared by selective laser melting was studied at cryogenic temperatures.The results demonstrate that the addition o...The tensile behavior of(Fe_(50)Mn_(30)Co_(10)Cr_(10))_(100-x)Si_(x)(x=0(Si0),2(Si2))metastable HEAs prepared by selective laser melting was studied at cryogenic temperatures.The results demonstrate that the addition of Si leads to lattice distortion and a decrease in stacking fault energy,especially at 77 K,which significantly promotes transformation-induced plasticity(TRIP)in Si2 HEAs.The yield strength,tensile strength,and ductility of Si2 HEAs are 505.2 MPa,1364.1 MPa,and 19%,which are 43%,53% and 58% higher than those of Si0 alloy,respectively.TRIP is the main deformation mode,in addition to dislocation slip,and plays a key role in strengthening.The reinforced and continuously sustained TRIP maintains a dynamic strain distribution during deformation.Ultrahigh strain hardening greatly enhances the strength and ductility.展开更多
Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(...Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.展开更多
N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core.Their photocatalytic activities in the degradation of d...N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core.Their photocatalytic activities in the degradation of dyes under visible light irradiation were investigated.The N-K2Ti4O9/UiO-66-NH2 composites exhibited higher photocatalytic activity than the pure components.This synergistic effect was due to the high adsorption capacity of UiO-66-NH2 and that the two components together induced an enhanced separation efficiency of photogenerated electron-hole pairs.The mass ratio of N-K2Ti4O9 to ZrCl4 of 3：7 in the composite exhibited the highest photocatalytic activity.Due to the electrostatic attraction between the negatively charged backbone of UiO-66-NH2with the positively charged groups of cationic dyes,the composites were more photocatalytically active for cationic dyes than for anionic dyes.展开更多
Lithium-oxygen(Li-O2)batteries are perceived as a promising breakthrough in sustainable electrochemical energy storage,utilizing ambient air as an energy source,eliminating the need for costly cathode materials,and of...Lithium-oxygen(Li-O2)batteries are perceived as a promising breakthrough in sustainable electrochemical energy storage,utilizing ambient air as an energy source,eliminating the need for costly cathode materials,and offering the highest theoretical energy density(~3.5 k Wh kg^(-1))among discussed candidates.Contributing to the poor cycle life of currently reported Li-O_(2)cells is singlet oxygen(1O_(2))formation,inducing parasitic reactions,degrading key components,and severely deteriorating cell performance.Here,we harness the chirality-induced spin selectivity effect of chiral cobalt oxide nanosheets(Co_(3)O_(4)NSs)as cathode materials to suppress 1O_(2)in Li-O_(2)batteries for the first time.Operando photoluminescence spectroscopy reveals a 3.7-fold and 3.23-fold reduction in 1O_(2)during discharge and charge,respectively,compared to conventional carbon paperbased cells,consistent with differential electrochemical mass spectrometry results,which indicate a near-theoretical charge-to-O_(2)ratio(2.04 e-/O_(2)).Density functional theory calculations demonstrate that chirality induces a peak shift near the Fermi level,enhancing Co 3d-O 2p hybridization,stabilizing reaction intermediates,and lowering activation barriers for Li_(2)O_(2)formation and decomposition.These findings establish a new strategy for improving the stability and energy efficiency of sustainable Li-O_(2)batteries,abridging the current gap to commercialization.展开更多
It is a challenge to develop complex-shaped Ni Ti shape memory alloy parts by traditional processing methods, due to the poor machinability of Ni Ti alloy. It is reported that selective laser melting(SLM) of additive ...It is a challenge to develop complex-shaped Ni Ti shape memory alloy parts by traditional processing methods, due to the poor machinability of Ni Ti alloy. It is reported that selective laser melting(SLM) of additive manufacturing could overcome this problem. However, the reported SLM-produced Ni Ti exhibits poor tensile ductility due to the inner defects and adverse unidirectional columnar grains from SLM process. In this work, the defect-less SLM-Ni Ti with nondirective columnar grains was fabricated by optimizing the intraformational laser scanning length and interformational laser scanning direction. The obtained lath-shaped SLM-Ni Ti sample exhibits tensile strain of 15.6%, more than twice of the reported maximum result(7%). Besides, the SLM-Ni Ti part with complex geometry displays a shape memory recovery of 99% under compressive deformation of 50%.展开更多
Silica-supported CuCo catalysts were prepared by impregnation method with different impregnation sequence for higher alcohols synthesis. These catalysts were characterized by H2-TPR, XRD, N2 adsorption, XPS techniques...Silica-supported CuCo catalysts were prepared by impregnation method with different impregnation sequence for higher alcohols synthesis. These catalysts were characterized by H2-TPR, XRD, N2 adsorption, XPS techniques and CO selective hydrogenation reaction measurement. The effects of impregnation sequence on the structure and performance of catalysts were investigated, and there were important influences on the selectivity to higher alcohols. There was a strong synergistic effect between copper and cobalt for the co-impregnated sample. The CuCo/SiO2 catalyst prepared by co- impregnation showed a better yield of total alcohols, and a higher selectivity to total alcohols which reached 51.5%.展开更多
Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SC...Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SCR） are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na＋ ion-exchanges with H＋and Cu2＋of Cu/SAPO-34. The exchange of H＋is easier than that of isolated Cu2＋. The exchanged Cu2＋ions aggregate and form ＂CuAl_2O4-like＂ species.The NH_3-SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu2＋and acid sites is responsible for the activity loss.展开更多
The morphology effect of Zr-doped CeOwas studied in terms of their activities in the selective oxidation of styrene to styrene oxide using tert-butyl hydroperoxide as the oxidant. In the present work, Zrdoped CeOnanor...The morphology effect of Zr-doped CeOwas studied in terms of their activities in the selective oxidation of styrene to styrene oxide using tert-butyl hydroperoxide as the oxidant. In the present work, Zrdoped CeOnanorods exhibited the highest catalytic performance（yield of styrene oxide and TOF value）followed by nanoparticles and nanocubes. For the Zr-doped CeOnanorods, the apparent activation energy is 56.3 k J/mol, which is much lower than the values of catalysts supported on nanoparticles and nanocubes（73.3 and 93.4 k J/mol）. The high resolution transmission electron microscopy results indicated that（100） and（110） crystal planes are predominantly exposed for Zr-doped CeOnanorods while（100）and（111） for nanocubes,（111） for nanoparticles. The remarkably increased catalytic activity of the Zrdoped CeOnanorods is mainly attributed to the higher percentage of Cespecies and more oxygen vacancies, which are associated with their exposed（100） and（110） crystal planes. Furthermore, recycling studies proved that the heterogeneous Zr-doped CeOnanorods did not lose its initial high catalytic activity after five successive recycles.展开更多
Carbon nanotube （CNT）-supported Ru nanoparticles with mean sizes ranging from 2.3 to 9.2 nm were prepared by different post-treatments and studied for Fischer-Tropsch （FT） synthesis. The effects of Ru particle siz...Carbon nanotube （CNT）-supported Ru nanoparticles with mean sizes ranging from 2.3 to 9.2 nm were prepared by different post-treatments and studied for Fischer-Tropsch （FT） synthesis. The effects of Ru particle size on catalytic behaviors were investigated at both shorter and longer contact times. At shorter contact time, where the secondary reactions were insignificant, the turnover frequency （TOF） for CO conversion was dependent on the mean size of Ru particles; TOF increased with the mean size of Ru particles from 2.3 to 6.3 nm and then decreased slightly. At the same time, the selectivities to C5＋ hydrocarbons increased gradually with the mean size of Ru particles up to 6.3 nm and then kept almost unchanged with a further increase in Ru particle size. At longer contact time, C10-C20 selectivity increased significantly at the expense of C21＋ selectivity, suggesting the occurrence of the selective hydrocracking of C21＋ to C10-C20 hydrocarbons.展开更多
Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation ch...Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation characteristics of methane recovered from mine gas based on hydrate method.The partition coefficient,separation factor and recovery rate were used to evaluate the effects of MMT,and the selection factor was primarily proposed to define the selectivity of mine gas hydrate in the relative target gases.The experimental results indicate that MMT could improve the following factors including hydration separation factor,the selection factor,the partition coefficient,and the recovery rate.Furthermore,the effect of SDS on the function of MMT is analyzed in the process of hydration separation.Finally,due to the results of the experiment,it is concluded that MMT hydration mechanism explores the effect of MMT enrichment methane from mine gas.展开更多
To evaluate the effect of distal point selection, local point selection, and distal-local point selection on acupuncture efficacy. Methods： According to the requirements of evidence-based medicine（EBM）, the literat...To evaluate the effect of distal point selection, local point selection, and distal-local point selection on acupuncture efficacy. Methods： According to the requirements of evidence-based medicine（EBM）, the literature on acupuncture with distal and local point selection in recent 20 years included in domestic and overseas medical databases was retrieved, and meta-analysis of the included articles was carried out. Results： Thirty-two articles were included finally, totaling 2829 patients. The results of meta-analysis indicated that the curative effect of distal-local point combination was superior to that of simple distal point selection or local point selection during acupuncture–moxibustion treatment for diseases, and there was no obvious difference in the curative effect between simple distal point selection and local point selection. According to the comprehensive analysis of 18 included articles, the difference in total effective rate between distal point selection and local point selection was not statistically significant, i.e. the curative effect of distal point selection and local point selection was equivalent [OR=0.83,95%CI（0.83,1.18）, Z=1.04, P0.01]. According to the comprehensive analysis of 20 included articles, the difference in total effective rate between local point selection and distal-local point selection was statistically significant, and the results indicated that the curative effect of distal-local point selection was superior to that of local point selection [OR=0.32, 95%CI（0.23,0.44）, Z=6.90, P0.01]. According to the comprehensive analysis of 8 included articles, the difference in total effective rate between distal point selection and distal-local point selection was statistically significant, and the results indicated that the curative effect of distal-local point selection was superior to that of distal point selection [OR=0.20,95%CI（0.10,0.40）, Z=4.50, P0.01]. In addition, the analysis of publication bias of this study indicated that publication bias might exist. Since the quality of included articles was generally lower, the above conclusion still needed to be supported by more evidence-based medicine proofs with high quality. Conclusion： The curative effect of distal-local point combination was superior to that of simple distal point selection or local point selection during acupuncture treatment for diseases, and there was no obvious difference in the curative effect between simple distal point selection and local point selection.展开更多
文摘The highly selective catalytic hydrogenation of halogenated nitroaromatics was achieved by employing Pd‑based catalysts that were co‑modified with organic and inorganic ligands.It was demonstrated that the catalysts contained Pd species in mixed valence states,with high valence Pd at the metal‑support interface and zero valence Pd at the metal surface.While the strong coordination of triphenylphosphine(PPh3)to Pd0 on the Pd surface prevents the adsorption of halogenated nitroaromatics and thus dehalogenation,the coordination of sodium metavanadate(NaVO3)to high‑valence Pd sites at the interface helps to activate H2 in a heterolytic pathway for the selective hydrogenation of nitro‑groups.The excellent catalytic performance of the interfacial active sites enables the selective hydrogenation of a wide range of halogenated nitroaromatics.
文摘This paper lays particular emphasis on pun's effectiveness and selectivity in English advertisements.The illustration and examples can help us understand the English advertisements well and foster our ability to appreciate the charm of English.
基金financially supported by the Jiangsu Agricultural Scientific Self-innovation Fund,China (CX(15)1057)the Fund of Science and Technology of Jiangsu Province,China (BE2015342)the National Key Research and Development Program of China (2017YFD0200400 and 2016YFD0300706)
文摘The green miridbug,Cyrtorhinus lividipennis,is an important predator of the rice brown planthopper,Nilaparvata lugens.In this study,the selective toxicity of seven commercial biopesticides for C.lividipennis was examined under laboratory conditions; abamectin was the most selective to C.lividipennis,followed by matrine and azadirachtin.Veratridine,rotenone,Bacillus thuringiensis and Beauveria bassiana showed less selectivity for C.lividipennis.Subsequently,matrine,abamectin and azadirachtin were selected for sublethal assessments with respect to C.lividipennis due to their high toxicities to N.lugens.C.lividipennis treated with sublethal concentrations(LC10 and LC20) of the three biopesticides could distinguish volatiles released from healthy and N.lugens-infested plants indicating that the biopesticides tested did not affect the foraging ability of surviving miridbugs.Azadirachtin decreased the consumption capability of C.lividipennis when the densities of N.lugens were 20,30,40 and 50 insects per vial.Sublethal concentration treatment did not impact the pre-oviposition period or egg hatchability of C.lividipennis.However,the fecundity of C.lividipennis exposed to azadirachtin and abamectin increased by 27–41% compared to the untreated individuals.In summary,abamectin or matrine together with C.lividipennis could be considered an effective,sustainable pest management strategy for rice.
文摘The electrochemical reduction of CO_(2)(eCO_(2)R)under ambient conditions is crucial for reducing carbon emissions and achieving carbon neutrality.Despite progress with alkaline and neutral electrolytes,their efficiency is limited by(bi)carbonates formation.Acidic media have emerged as a solution,addressing the(bi)carbonates challenge but introducing the issue of the hydrogen evolu-tion reaction(HER),which reduces CO_(2) conversion efficiency in acidic environments.This review focuses on enhancing the selectivity of acidic CO_(2) electrolysis.It commences with an overview of the latest advancements in acidic CO_(2) electrolysis,focusing on product selectivity and electrocatalytic activity enhancements.It then delves into the critical factors shaping selectivity in acidic CO_(2) electrolysis,with a special emphasis on the influence of cations and catalyst design.Finally,the research challenges and personal perspectives of acidic CO_(2) electrolysis are suggested.
基金supported by National Nature Science Foundation of China(Nos.92161202 and 22121005)China Postdoctoral Science Foundation(Nos.2023M741814 and 2023M741815)+2 种基金Postdoctoral Fellowship Program of CPSF(No.GZC20231170)Natural Science Foundation of Science&Technology Department of Sichuan Province(No.2023NSFSC110)Research and Innovation Team of China West Normal University(No.KCXTD2023-1)。
文摘Selective catalytic transfer hydrogenation(CTH)of carbonyl compounds to obtain specific alcohols holds significant importance across various fields.Achieving multiple selectivity in CTH is particularly crucial,but full of great challenge.Herein,a cationic In-captured Zr-porphyrin framework(1)with nanosized pores/cages was successfully constructed and showed high structure stability.Catalytic investigations revealed that 1 displayed highly multi-selective CTH of aldehydes and ketones containing both chemo-and size selectivity for the first time.The CTH of aldehydes and ketones exhibited remarkable reductive selectivity of 99%towards C=O bonds into CH–OH in the presence of-NO_(2),-CN and C=C groups.Through tuning the reaction conditions,1 also exhibited highly selective reduction of 97%for-CHO groups in the simultaneous presence of-CHO and-COCH3groups in intra-and intermolecular settings.Remarkably,reductive selectivity towards-CHO group remained prominent among five concurrent unsaturated groups mentioned above.Additionally,the definite pore size of 1 facilitated volume control of substrates,enabling size selectivity.1 as a heterogeneous catalyst was further confirmed by leaching tests,and maintained high activity even after being used for at least six cycles.Mechanistic studies have revealed that Zr6O8clusters served as the catalytic centers and the observed chemoselectivity mainly results from the synergistic effect of distinct metal sites within 1.The heightened selectivity towards-CHO over-COCH_(3)can be attributed to the easier realization of transfer hydrogenation processes for-CHO compared to-COCH_(3).
基金financially supported by the National Natural Science Foundation of China(Nos.22301155,22171156,21803001)Taishan Scholar Foundation of Shandong Province(China)+2 种基金the Natural Science Foundation of Shandong Province(No.ZR2023QB122)Shandong Province Excellent Youth Innovation TeamStartup Funds from Qingdao University of Science and Technology
文摘Understanding the synergistic effect between ligands at the atomic level to control the catalytic selectivity of catalysts remains a significant challenge due to the complexity of ligand interactions and limitations in current analytical techniques.Herein,using precisely structured metal nanoclusters as models,we discovered that altering the electronegativity of substituents on donor thiolate ligands can modulate the bond dissociation energy of coordinated phosphine ligands on the clusters.This change leads to the selective dissociation of ligands during the catalytic process,thereby enabling control over catalytic selectivity with an abrupt increase in formate production from~0%to 23%.This work provides crucial insights into understanding ligand interactions on metal nanoparticle surfaces at the atomic level and lays the foundation for designing highly selective catalysts in the future.
基金supported by Program for Innovative Research Team in Science and Technology in Fujian Province University,Chinathe Natural Science Foundation of Fujian Province,China(Nos.2023J011013,2020J01898)。
文摘The tensile behavior of(Fe_(50)Mn_(30)Co_(10)Cr_(10))_(100-x)Si_(x)(x=0(Si0),2(Si2))metastable HEAs prepared by selective laser melting was studied at cryogenic temperatures.The results demonstrate that the addition of Si leads to lattice distortion and a decrease in stacking fault energy,especially at 77 K,which significantly promotes transformation-induced plasticity(TRIP)in Si2 HEAs.The yield strength,tensile strength,and ductility of Si2 HEAs are 505.2 MPa,1364.1 MPa,and 19%,which are 43%,53% and 58% higher than those of Si0 alloy,respectively.TRIP is the main deformation mode,in addition to dislocation slip,and plays a key role in strengthening.The reinforced and continuously sustained TRIP maintains a dynamic strain distribution during deformation.Ultrahigh strain hardening greatly enhances the strength and ductility.
基金financially supported by National Natural Science Foundation of China(22466010)Guizhou Provincial Basic Research Program(Natural Science)ZK[2023]47 and key program ZD[2025]075+6 种基金Innovation and Entrepreneurship Project for overseas Talents in Guizhou Province[2022]02Specific Natural Science Foundation of Guizhou University(X202207)the national undergraduate innovation and entrepreneurship training program(gzugc2023006gzusc2024012)SRT project of Guizhou university(2023SRT0292023SRT024)supported by Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University。
文摘Electrocatalytic nitrate reduction reaction(NO3RR)represents a sustainable and environmentally benign route for ammonia(NH3)synthesis.However,NO3RR is still limited by the competition from hydrogen evolution reaction(HER)and the high energy barrier in the hydrogenation step of nitrogen-containing intermediates.Here,we report a selective etching strategy to construct Ru M nanoalloys(M=Fe,Co,Ni,Cu)uniformly dispersed on porous nitrogen-doped carbon substrates for efficient neutral NH3electrosynthesis.Density functional theory calculations confirm that the synergic effect between Ru and transition metal M modulates the electronic structure of the alloy,significantly lowering the energy barrier for the conversion of*NO_(2)to*HNO_(2).Experimentally,the optimized Ru Fe-NC catalyst achieves 100%Faraday efficiency with a high yield rate of 0.83 mg h^(-1)mg^(-1)catat a low potential of-0.1 V vs.RHE,outperforming most reported catalysts.In situ spectroscopic analyses further demonstrate that the Ru M-NC effectively promotes the hydrogenation of nitrogen intermediates while inhibiting the formation of hydrogen radicals,thereby reducing HER competition.The Ru FeNC assembled Zn-NO_(3)^(-)battery achieved a high open-circuit voltage and an outstanding power density and capacity,which drive selective NO_(3)^(-)conversion to NH3.This work provides a powerful synergistic design strategy for efficient NH3electrosynthesis and a general framework for the development of advanced multi-component catalysts for sustainable nitrogen conversion.
基金supported by the National Natural Science Foundation of China (51372062)the Anhui Provincial Natural Science Foundation(1508085MB28,1308085MB21)~~
文摘N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core.Their photocatalytic activities in the degradation of dyes under visible light irradiation were investigated.The N-K2Ti4O9/UiO-66-NH2 composites exhibited higher photocatalytic activity than the pure components.This synergistic effect was due to the high adsorption capacity of UiO-66-NH2 and that the two components together induced an enhanced separation efficiency of photogenerated electron-hole pairs.The mass ratio of N-K2Ti4O9 to ZrCl4 of 3：7 in the composite exhibited the highest photocatalytic activity.Due to the electrostatic attraction between the negatively charged backbone of UiO-66-NH2with the positively charged groups of cationic dyes,the composites were more photocatalytically active for cationic dyes than for anionic dyes.
基金supported by Basic Science Research Program(Priority Research Institute)through the NRF of Korea funded by the Ministry of Education(2021R1A6A1A10039823)by the Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Education(2020R1A6C101B194)。
文摘Lithium-oxygen(Li-O2)batteries are perceived as a promising breakthrough in sustainable electrochemical energy storage,utilizing ambient air as an energy source,eliminating the need for costly cathode materials,and offering the highest theoretical energy density(~3.5 k Wh kg^(-1))among discussed candidates.Contributing to the poor cycle life of currently reported Li-O_(2)cells is singlet oxygen(1O_(2))formation,inducing parasitic reactions,degrading key components,and severely deteriorating cell performance.Here,we harness the chirality-induced spin selectivity effect of chiral cobalt oxide nanosheets(Co_(3)O_(4)NSs)as cathode materials to suppress 1O_(2)in Li-O_(2)batteries for the first time.Operando photoluminescence spectroscopy reveals a 3.7-fold and 3.23-fold reduction in 1O_(2)during discharge and charge,respectively,compared to conventional carbon paperbased cells,consistent with differential electrochemical mass spectrometry results,which indicate a near-theoretical charge-to-O_(2)ratio(2.04 e-/O_(2)).Density functional theory calculations demonstrate that chirality induces a peak shift near the Fermi level,enhancing Co 3d-O 2p hybridization,stabilizing reaction intermediates,and lowering activation barriers for Li_(2)O_(2)formation and decomposition.These findings establish a new strategy for improving the stability and energy efficiency of sustainable Li-O_(2)batteries,abridging the current gap to commercialization.
基金supported by the National Key R&D Program of China (No. 2018YFB1105100)the Science Foundation of China University of Petroleum, Beijing (No. 2462018BJC005)+1 种基金the Joint Fund of Ministry of Education for Pre-research of Equipment (No. 6141A020222)the fourth batch of pre-research projects for manned spaceflight (No. 040202)
文摘It is a challenge to develop complex-shaped Ni Ti shape memory alloy parts by traditional processing methods, due to the poor machinability of Ni Ti alloy. It is reported that selective laser melting(SLM) of additive manufacturing could overcome this problem. However, the reported SLM-produced Ni Ti exhibits poor tensile ductility due to the inner defects and adverse unidirectional columnar grains from SLM process. In this work, the defect-less SLM-Ni Ti with nondirective columnar grains was fabricated by optimizing the intraformational laser scanning length and interformational laser scanning direction. The obtained lath-shaped SLM-Ni Ti sample exhibits tensile strain of 15.6%, more than twice of the reported maximum result(7%). Besides, the SLM-Ni Ti part with complex geometry displays a shape memory recovery of 99% under compressive deformation of 50%.
基金National Natural Science Foundation of China(20590360)New Century Excellent Talent Project of China(NCET-05-0783)
文摘Silica-supported CuCo catalysts were prepared by impregnation method with different impregnation sequence for higher alcohols synthesis. These catalysts were characterized by H2-TPR, XRD, N2 adsorption, XPS techniques and CO selective hydrogenation reaction measurement. The effects of impregnation sequence on the structure and performance of catalysts were investigated, and there were important influences on the selectivity to higher alcohols. There was a strong synergistic effect between copper and cobalt for the co-impregnated sample. The CuCo/SiO2 catalyst prepared by co- impregnation showed a better yield of total alcohols, and a higher selectivity to total alcohols which reached 51.5%.
基金financially supported by the National Key Research and Development program(No.2017YFC0211302)the National Natural Science Foundation of China(No.21676195)+1 种基金the Science Fund of State Key Laboratory of Engine Reliability(No.skler-201714)finical support from GM Global Research&Development(No.GAC1539)
文摘Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SCR） are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na＋ ion-exchanges with H＋and Cu2＋of Cu/SAPO-34. The exchange of H＋is easier than that of isolated Cu2＋. The exchanged Cu2＋ions aggregate and form ＂CuAl_2O4-like＂ species.The NH_3-SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu2＋and acid sites is responsible for the activity loss.
基金the financial support from NNSFC(Project 21373054,21303023,21173052)the Natural Science Foundation of Shanghai Science and Technology Committee(08DZ2270500)
文摘The morphology effect of Zr-doped CeOwas studied in terms of their activities in the selective oxidation of styrene to styrene oxide using tert-butyl hydroperoxide as the oxidant. In the present work, Zrdoped CeOnanorods exhibited the highest catalytic performance（yield of styrene oxide and TOF value）followed by nanoparticles and nanocubes. For the Zr-doped CeOnanorods, the apparent activation energy is 56.3 k J/mol, which is much lower than the values of catalysts supported on nanoparticles and nanocubes（73.3 and 93.4 k J/mol）. The high resolution transmission electron microscopy results indicated that（100） and（110） crystal planes are predominantly exposed for Zr-doped CeOnanorods while（100）and（111） for nanocubes,（111） for nanoparticles. The remarkably increased catalytic activity of the Zrdoped CeOnanorods is mainly attributed to the higher percentage of Cespecies and more oxygen vacancies, which are associated with their exposed（100） and（110） crystal planes. Furthermore, recycling studies proved that the heterogeneous Zr-doped CeOnanorods did not lose its initial high catalytic activity after five successive recycles.
基金supported by the National Basic Research Program of China (No. 2013CB933100)the National Natural Science Foundation of China (21173174, 21161130522, 21033006 and 20923004)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1036)the Research Fund for the Doctoral Program of Higher Education (No. 20090121110007)
文摘Carbon nanotube （CNT）-supported Ru nanoparticles with mean sizes ranging from 2.3 to 9.2 nm were prepared by different post-treatments and studied for Fischer-Tropsch （FT） synthesis. The effects of Ru particle size on catalytic behaviors were investigated at both shorter and longer contact times. At shorter contact time, where the secondary reactions were insignificant, the turnover frequency （TOF） for CO conversion was dependent on the mean size of Ru particles; TOF increased with the mean size of Ru particles from 2.3 to 6.3 nm and then decreased slightly. At the same time, the selectivities to C5＋ hydrocarbons increased gradually with the mean size of Ru particles up to 6.3 nm and then kept almost unchanged with a further increase in Ru particle size. At longer contact time, C10-C20 selectivity increased significantly at the expense of C21＋ selectivity, suggesting the occurrence of the selective hydrocracking of C21＋ to C10-C20 hydrocarbons.
基金Projects(51404102,51334005,51274267)supported by the National Natural Science Foundation of ChinaProject(UNPYSCT-2017140)supported by the Youth Innovation Personnel Training in University and College of Heilongjiang Province,China
文摘Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation characteristics of methane recovered from mine gas based on hydrate method.The partition coefficient,separation factor and recovery rate were used to evaluate the effects of MMT,and the selection factor was primarily proposed to define the selectivity of mine gas hydrate in the relative target gases.The experimental results indicate that MMT could improve the following factors including hydration separation factor,the selection factor,the partition coefficient,and the recovery rate.Furthermore,the effect of SDS on the function of MMT is analyzed in the process of hydration separation.Finally,due to the results of the experiment,it is concluded that MMT hydration mechanism explores the effect of MMT enrichment methane from mine gas.
文摘To evaluate the effect of distal point selection, local point selection, and distal-local point selection on acupuncture efficacy. Methods： According to the requirements of evidence-based medicine（EBM）, the literature on acupuncture with distal and local point selection in recent 20 years included in domestic and overseas medical databases was retrieved, and meta-analysis of the included articles was carried out. Results： Thirty-two articles were included finally, totaling 2829 patients. The results of meta-analysis indicated that the curative effect of distal-local point combination was superior to that of simple distal point selection or local point selection during acupuncture–moxibustion treatment for diseases, and there was no obvious difference in the curative effect between simple distal point selection and local point selection. According to the comprehensive analysis of 18 included articles, the difference in total effective rate between distal point selection and local point selection was not statistically significant, i.e. the curative effect of distal point selection and local point selection was equivalent [OR=0.83,95%CI（0.83,1.18）, Z=1.04, P0.01]. According to the comprehensive analysis of 20 included articles, the difference in total effective rate between local point selection and distal-local point selection was statistically significant, and the results indicated that the curative effect of distal-local point selection was superior to that of local point selection [OR=0.32, 95%CI（0.23,0.44）, Z=6.90, P0.01]. According to the comprehensive analysis of 8 included articles, the difference in total effective rate between distal point selection and distal-local point selection was statistically significant, and the results indicated that the curative effect of distal-local point selection was superior to that of distal point selection [OR=0.20,95%CI（0.10,0.40）, Z=4.50, P0.01]. In addition, the analysis of publication bias of this study indicated that publication bias might exist. Since the quality of included articles was generally lower, the above conclusion still needed to be supported by more evidence-based medicine proofs with high quality. Conclusion： The curative effect of distal-local point combination was superior to that of simple distal point selection or local point selection during acupuncture treatment for diseases, and there was no obvious difference in the curative effect between simple distal point selection and local point selection.
