Nature Communications
·
2022
·Vol. 13
·期 1
·1-11
·
IF 17.694
Xia Nan,Xing Jianpei,Peng Di,Ji Shiyu,Zha Jun,Yan Nan,Su Yan,Jiang Xue,Zeng Zhi,Zhao Jijun,Wu Zhikun
Nanoparticle assembly paves the way for unanticipated properties and applications from the nanoscale to the macroscopic world. However, the study of such material systems is greatly inhibited due to the obscure compositions and structures of nanoparticles (especially the surface structures). The assembly of atomically precise nanoparticles is challenging, and such an assembly of nanoparticles with metal core sizes strictly larger than 1 nm has not been achieved yet. Here, we introduced an on-site synthesis-and-assembly strategy, and successfully obtained a straight-chain assembly structure consisting of Ag 77 Cu 22 (CHT) 48 (CHT: cyclohexanethiolate) nanoparticles with two nanoparticles separated by one S atom, as revealed by mass spectrometry and single crystal X-ray crystallography. Although Ag 77 Cu 22 (CHT) 48 bears one unpaired shell-closing electron, the magnetic moment is found to be mainly localized at the S linker with magnetic isotropy, and the sulfur radicals were experimentally verified and found to be unstable after disassembly, demonstrating assembly-induced spin transfer. Besides, spin nanoparticles are found to couple and lose their paramagnetism at sufficiently short inter-nanoparticle distance, namely, the spin coupling depends on the inter-nanoparticle distance. However, it is not found that the spin coupling leads to the nanoparticle growth.
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高影响因子
ACS Omega
·
2020
·
IF 2.87
Xiaomei Qin,Shihao Yang,Yapei Chen,Xiaoyun Qin,Jianbo Zhao,Wenjun Fang,Dan Luo
Palladium nanoparticles, which were prepared by modified hyperbranched polyglycerol (mHPG) as stabilizers, can be dispersed well in nonpolar organic solvents and form highly stable nanofluids. The influences of three mHPG products modified with cyclohexanethiol (CSHPG), dodecanethiol (DSHPG), and octadecanethiol (OSHPG) on the preparation and stability of the palladium nanoparticles were investigated. The stability and thermal conductivity enhancement of the hydrocarbon-based nanofluids with Pd@mHPG (Pd@CSHPG, Pd@DSHPG, and Pd@OSHPG) compared to the corresponding base fluid were investigated at different temperatures. The average diameters of nanoparticles stabilized by CSHPG, DSHPG, and OSHPG are within 2.7–3.6 nm. The palladium nanoparticles could be dispersed well in the nonpolar base fluid such as decalin. The nanofluids with Pd@DSHPG and Pd@OSHPG could remain stable for up to 330 days at room temperature. The nanofluid with Pd@DSHPG or Pd@OSHPG could be stable for more than 24 h at 110 °C. The thermal conductivity of the nanofluids improved with increasing temperature and the mass fraction of nanoparticles compared to the corresponding base fluid. The long alkyl chain-modified HPG can give better protection for nanoparticles from agglomeration and assist metal nanoparticles in enhancing the thermal conductivity of nanofluids.
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FUEL
·
2020
·
IF 5.578
Dongfang Li,Shang Ma,Abdelatif Laroui,Yixian Zhang,Jie Wang,Ping Lu,Jian Dong
Subsea natural gas drilling and gas transport is challenged by the catastrophic formation of gas clathrate hydrate in production lines. Polymer inhibitors are vital to mitigate this technical problem in subsea gas drilling operation . However, physico- chemical factors affecting their performance are not yet completely known. Herein, we report that the activities of synthetic kinetic inhibitors of clathrate hydrates are correlated to the surrounding water dynamics. Two types of linear polyamide inhibitors are found to be capable of producing immobilized nonfreezable water molecules with fast transverse relaxation in sub-millisecond to millisecond time-scale as revealed by NMR relaxometry. Such a unique state of water can be construed as a form of nonfreezable bound water measured by differential scanning calorimetry . The quantity of such water species can be tuned by the size of the hydrophobic groups introduced to the polyamides and result in longer inhibition time before the rapid growth of the hydrate crystals. Addition of a single hydroxyl side group in the polymer structural unit can also affect the dependence of the kinetic inhibition time on the amount of the supercooled water. Both the hydrophobic and hydrophilic groups in the polymer inhibitors exert coordinated influence on the dynamic properties of the bound water, which are responsible for the early recognition and inhibition of the clathrate hydrate clusters.
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INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Ting Yang,Zheng Chen,Ziqing Wang,Jiayuan Yu,Changjiu Xia,Hongxia Liu,Lei Liu,Xinxin Peng,Yibin Luo,Xingtian Shu
Disulfide is an important organic reagent and synthetic intermediate that is widely used in organic synthesis, polymers, and other fields, but its synthesis still suffers from many environmental pollution and economic problems. Here, we present an environmentally friendly and efficient base-free aerobic oxidative thiol coupling catalyzed by heterogeneous CoOx nanoclusters entrapped in hierarchical silicalite-1 zeolite, synthesized by combining silane pore expansion and metal coordination methods under hydrothermal conditions. It is confirmed that open hierarchical channels favor mass diffusion, and the chemical valence of Co species in CoOx/h-S-1-H is +2, which is different from that of Co3O4 particles in CoOx/h-S-1-I. CoOx nanoclusters, are strongly fixed in the channels of silicalite-1 zeolite via Co−O−Si bonds, which is of great importance for the high catalytic activity in both symmetrical and unsymmetrical oxidative thiol coupling reactions. After recycling experiments four times, the CoOx/h-S-1-H used has almost the same chemical state and the same distribution of Co(II) species as the fresh catalysts. Based on DFT calculations and inhibition experiments, the oxidative coupling of thiols undergoes a free radical mechanism in which Co(III) causes RS−H cleavage into RS· and H· species. Subsequently, two RS· radicals are coupled to disulfides, while H· radicals react with the O species to form H2O molecules. This work not only provides guidance on catalyst design and parameter optimization for oxidative thiol coupling but also advances the understanding of the aerobic oxidation mechanism.
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DALTON TRANSACTIONS
·
2025
·Vol. 54
·期 23
·9160-9168
·
IF 3.3
Jiansheng Ye,Yali Dai,Wenjun Liu,Jingrou Xu,Jialing Li,Meng Chen,Sha Yang,Qinzhen Li,Yuanxin Du,Jinsong Chai,Manzhou Zhu
Taking Au36(CHT)24 (Au36 for short) as a precursor, a Au32(CHT)20(TFP) (Au32 for short) nanocluster is obtained with the aid of a phosphine-mediated approach. Structural analysis shows that Au32 is obtained by modifying and transforming the surface structure of the parent Au36 nanocluster, including the removal of a surface layer of the core structure and the rearrangement of the surface motifs. Most importantly, this structural transformation results in a change in the position of some of the surface motifs, thus exposing the active domain with bare core metal atoms. The electrocatalytic CO2 reduction reaction is introduced to investigate the effect of the modification of the surface structure on its properties. The results show that the modified structure of Au32 exhibits superior catalytic activity with a faradaic efficiency (for CO) of 97.7% at −0.8 V.
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高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Nan Xia,Wei Wang,Shengli Zhuang,Shenxia Huang,Wanmiao Gu,Jin Li,Haiteng Deng,Yaobing Wang,Zhikun Wu
Due to the challenge of finding adequate structures for the catalytic activity assessment of various staples in metal nanoclusters, a fast-oxidation method is introduced to obtain a kinetics-controlled metal nanocluster Au 24 (CHT) 18 with modified structure of the previously reported Au 24 (SR) 20 (SR: thiolate). It is found that the staple catalysis activity is affected by the kernel, transforming the catalysis selectivity from H 2 evolution to CO production [H 2 Faradaic efficiency: ≈100% for Au 24 (SR) 20 at −0.8 V versus CO Faradaic efficiency: 91% for Au 24 (SR) 18 ], and the staple catalysis activity order is tetramer > monomer > dimer, which is further confirmed by comparing the catalysis performance between Au 24 (CHT) 18 and Au 18 (CHT) 14 . Thus, the kernel influence on the staple catalysis and the staple activity order in catalysis is revealed, and with essential implications provided for metal nanocluster synthesis, structure tailoring, and structure–property correlation. The additional photoluminescence endows the as-prepared nanoclusters potential for more practical applications.
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