Search

We report a flame‐reaction method to synthesize high‐performance SmxCoy (x=1, y=5; x=2, y=17) particles on a multigram scale. This flame reaction allows the controlled decomposition of Sm(NO3)3 and Co(NO3)2 to 320 nm SmCo‐O (SmCoO3 + Co3O4) particles. A 5.8 g sample of SmCo3.8‐O particles was coated with CaO and then reduced at 900 °C by Ca to give 4.2 g of 260 nm SmCo5 particles. The SmCo5 particles are strongly ferromagnetic and the aligned particles in epoxy resin exhibit a large room‐temperature coercivity (Hc) of 41.8 kOe and giant (BH)max (maximum magnetic energy product) of 19.6 MGOe, the highest value ever reported for SmCo5 made by chemical methods. This synthesis can be extended to synthesize Sm2Co17 particles, providing a general approach to scaling up the synthesis of high‐performance SmxCoy nanomagnets for permanent magnet applications. [ABSTRACT FROM AUTHOR]

We report a new strategy to prepare a composite catalyst for highly efficient electrochemical CO2 reduction reaction (CO2RR). The composite catalyst is made by anchoring Au nanoparticles on Cu nanowires via 4,4′‐bipyridine (bipy). The Au‐bipy‐Cu composite catalyzes the CO2RR in 0.1 m KHCO3 with a total Faradaic efficiency (FE) reaching 90.6 % at −0.9 V to provide C‐products, among which CH3CHO (25 % FE) dominates the liquid product (HCOO−, CH3CHO, and CH3COO−) distribution (75 %). The enhanced CO2RR catalysis demonstrated by Au‐bipy‐Cu originates from its synergistic Au (CO2 to CO) and Cu (CO to C‐products) catalysis which is further promoted by bipy. The Au‐bipy‐Cu composite represents a new catalyst system for effective CO2RR conversion to C‐products. [ABSTRACT FROM AUTHOR]

We report a general chemical approach to synthesize strongly ferromagnetic rare‐earth metal (REM) based SmCo and SmFeN nanoparticles (NPs) with ultra‐large coercivity. The synthesis started with the preparation of hexagonal CoO+Sm2O3 (denoted as SmCo‐O) multipods via decomposition of Sm(acac)3 and Co(acac)3 in oleylamine. These multipods were further reduced with Ca at 850 °C to form SmCo5 NPs with sizes tunable from 50 to 200 nm. The 200 nm SmCo5 NPs were dispersed in ethanol, and magnetically aligned in polyethylene glycol (PEG) matrix, yielding a PEG‐SmCo5 NP composite with the room temperature coercivity (Hc) of 49.2 kOe, the largest Hc among all ferromagnetic NPs ever reported, and saturated magnetic moment (Ms) of 88.7 emu g−1, the highest value reported for SmCo5 NPs. The method was extended to synthesize other ferromagnetic NPs of Sm2Co17, and, for the first time, of Sm2Fe17N3 NPs with Hc over 15 kOe and Ms reaching 127.9 emu g−1. These REM based NPs are important magnetic building blocks for fabrication of high‐performance permanent magnets, flexible magnets, and printable magnetic inks for energy and sensing applications. A new chemical process is developed to prepare strongly ferromagnetic SmCo5 nanoparticles (NPs) via controlled reduction of SmCo‐O multipods. The 200 nm SmCo5 NPs embedded in polyethylene glycol are aligned magnetically and show the room temperature coercivity of 49.2 kOe. The synthetic method has also been extended to prepare ferromagnetic Sm2Co17 and Sm2Fe17N3 NPs. [ABSTRACT FROM AUTHOR]

We report a facile method for assembly of a monolayer array of nitrogen-doped graphene (NG) and nanoparticles (NPs) and the subsequent transfer of two layers onto a solid substrate (S). Using 3 nm NiPd NPs as an example, we demonstrate that NiPd-NG-Si (Si=silicon wafer) can function as a catalyst and show maximum NiPd catalysis for the hydrolysis of ammonia borane (H3NBH3, AB) with a turnover frequency (TOF) of 4896.8 h−1 and an activation energy ( Ea) of 18.8 kJ mol−1. The NiPd-NG-S catalyst is also highly active for catalyzing the transfer hydrogenation from AB to nitro compounds, leading to the green synthesis of quinazolines in water. Our assembly method can be extended to other graphene and NP catalyst materials, providing a new 2D NP catalyst platform for catalyzing multiple reactions in one pot with maximum efficiency. [ABSTRACT FROM AUTHOR]

We report a new strategy to prepare a composite catalyst for highly efficient electrochemical CO2 reduction reaction (CO2RR). The composite catalyst is made by anchoring Au nanoparticles on Cu nanowires via 4,4′‐bipyridine (bipy). The Au‐bipy‐Cu composite catalyzes the CO2RR in 0.1 m KHCO3 with a total Faradaic efficiency (FE) reaching 90.6 % at −0.9 V to provide C‐products, among which CH3CHO (25 % FE) dominates the liquid product (HCOO−, CH3CHO, and CH3COO−) distribution (75 %). The enhanced CO2RR catalysis demonstrated by Au‐bipy‐Cu originates from its synergistic Au (CO2 to CO) and Cu (CO to C‐products) catalysis which is further promoted by bipy. The Au‐bipy‐Cu composite represents a new catalyst system for effective CO2RR conversion to C‐products. [ABSTRACT FROM AUTHOR]