Li Chen,Yitan Wang,Jiangdong Dai,Minjia Meng,Xiaohui Dai,Jianming Pan
Molecular imprinting technology has been proved an efficient strategy for separation, however ion imprinting was not so high-performance. Pure aqueous phase synthesis and ligand assistance are two prominent improvement strategies so far. This article developed a novel rare earth yttrium(Y) ion imprinted membrane (Y-IIM) in pure aqueous phase, and applied a high-performance rare earth extractant Cyanex272 as ligand in membrane basement to confine the imprinted polymerization process. Firstly, polymer inclusion membrane (PIM) containing copolymer poly(vinyl alcohol-co-ethylene) as hydrophilic additive and Cyanex272 as interior ion ligand was synthesized. Then ion imprinting in aqueous phase was initiated through redox polymerization. Results confirmed that Y-IIMs performed superior hydrophility and Cyanex272 presented improved thermal stability. Imprinted aggregates distributed separately on membrane surfaces and inner walls, as a result of the confinement by the coordination between Y and Cyanex272 ligand. The adsorption capacity on Y was 3 times that of non-imprinted membranes, and the Y-IIMs exhibited superior permeation ability for Y than Ho and Er, indicating the realization of expected specific recognition affinity for Y through ligand confinement and aqueous medium synthesis.
Electrochemical nitrate reduction to NH 3 holds a great promise for N-upcycling in nature, while its sluggish reaction kinetics involved in both the stepwise deoxygenation and hydrogenation processes necessitates the development of bespoke catalysts with multi-site engineering. Herein, we report a hybrid catalyst composed of rare-earth (RE) yttrium (Y) single atoms and copper phosphide (Cu 3 P) nanoparticles loaded on N, P-doped carbon (Y SA -Cu 3 P/CNP) through a chelating and pyrolysis method. Owing to a synergistic contribution of Y single atoms and Cu 3 P nanoparticles, Y SA -Cu 3 P/CNP achieves an impressive NH 3 Faradaic efficiency (FE) of 92% at − 0.5 V(vs. RHE) and the highest NH 3 yield rate of 11.4 mg·h −1 ·cm −2 at − 0.6 V (vs. RHE) in an alkaline media, which surpass most of the reported electrocatalysts. The intricate reaction pathway has been explored by online differential electrochemical mass spectrometry (DEMS), and the synergistic effect between Y single atoms and Cu 3 P nanoparticles has been studied by in situ synchrotron X-ray absorption spectroscopy. Moreover, density-functional theory (DFT) calculations unveil that the high-efficiency nitrate reduction on Y SA -Cu 3 P/CNP is attributed to a reduced energy barrier of the rate-determining deoxygenation step coupled with the enhanced stabilization of active hydrogen favorable for the hydrogenation steps, thereby boosting the overall reaction rates. In addition, a prototype Zn-nitrate battery utilizing Y SA -Cu 3 P/CNP as the cathode is unveiled. This work not only elucidates the mechanism behind the enhanced catalytic performance but also paves the way for the future development of high-efficiency electrocatalysts through dual-site engineering. Graphical Abstract
Lin He,Yimin Gao,Yefei Li,Zhiwei Liu,Weiyao Zhang,Guangcan Zhou,Hongying He,Siyong Zhao,Honggang Liu,Wentao Yan
Ti(C,N)-304ss cermets with various rare earth yttrium addition were fabricated via powder metallurgy . Fe and Cr atoms dissolved into Ti(C,N) grains and formed a core-rim structure. The first-principle method was employed to calculate the lattice parameters and elastic modulus of the solid solution. The formation of solid solution not only reduced the lattice misfit between the binder phase and hard phase but also improved the hardness of hard phase. The in-situ formed nano-Y 2 O 3 particles existed at the center of Ti(C,N) grains acting as ‘mid effect’ heteromorphic nuclei. The microstructure of cermets was refined with Y addition and the abnormal growth of hard phase was suppressed. The mechanical properties were also improved with Y addition. When the Y content reached 0.3 wt%, the optimal mechanical properties were obtained with a TRS value of 1527 MPa and a hardness value of 91.7 HRA.
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