Carbon-coated Ni nanoparticles supported on N-doped carbon enable efficient electroreduction of CO2 to CO comparable to single Ni sites.

There has been an intense research to develop 2-H MoS2 based catalysts to reduce or eliminate the use of Pt/C at higher metal loading for hydrogen evolution reaction (HER) in catalytic hydrolysis of water, which enables the capture of renewable energy sources as fuel and chemical. However, the study of its uncommon polymorph, 1T-MoS2 and particularly the doping effect with transition metal (TM) is rather limited due to the instability of this phase. Here we report a simple ambient temperature modification method using sonication to dope the single layer 1T-S MoS2 with various TM precursors. It is found that 1-T S MoS2 is more superior than corresponding 2H-S MoS2 and the inclusion of 3 wt% Pt or Pd can also further enhance the HER activity. STEM-EELS and XAS show the active single TM atom doping on this surface is to account for the high activity. Kinetic and DFT analyses also illustrate that the metallic nature of 1T-S MoS2 greatly facilitates the first proton reduction step from water, rendering it non-rate limiting as contrast to that of 2H-S MoS2. The inclusion of TM single doper such as Pd, despite at low loading, can offer the dramatic acceleration on the rate limiting recombination of H to H2. As a result, a bifunctional catalysis for HER over this tailored composite structure is demonstrated which outperforms most reported catalysts in this area.

Diluted magnetic semiconductors (DMSs) have drawn much attention and interesting in recent years because of the possibility involving charge and spin degrees of freedom in a single substance [1]. However, as dimension closed to nanoscale, the quantum effect will also be even more apparent. One-dimensional (1-D) nanowire heterostructures are potentially functionalities feasible for nanoscale electronics and optoelectronics [2,3]. Hence, synthesis of DMS nanowire heterostructure is of particular interest in nanoscale spintronics. Moreover, it is necessary to understand the correlation of magnetic properties and microstructure in DMSs with spatial resolution of near or even better than nanometer scale.In this letter, we study a systematic work of synthesis, microstructure, and magnetic measurements on 1-D Fe-doped Zn 1-X Cu X O nanowires. These are synthesized and proceeded by using thermal evaporation and ion implantation, in which the dose of the Fe ions implanted into the Zn 1-X Cu X O nanowires are 3 x 10 16 cm -2 , and 5 x 10 16 cm -2 , respectively. Atomic scale structural characterization including high-resolution transition electron microscope (HRTEM), and nanobeam energy dispersive x-ray spectroscopy (EDX) map were done to study the behavior of Fe atoms. Figure 1(b) shows the HRTEM image of Fe-doped Zn 1-X Cu X O nanowires with the [0001] growth direction of single crystal, which is the same as that of as-grown Zn 1-X Cu X O nanowire (Fig. (a)), for the dose of 5×10 16 ions/cm 2 . It also suggests that any nano-sized clusters or second phase are absence in the Fe-doped Zn 1-X Cu X O nanowires. Figure 2 is the subsequently EDX elemental map analysis. It is apparent that Fe element is successfully doped into Zn 1-X Cu X O nanowires of well-controlled size and exhibits gradually enhanced magnetic behavior with increasing Fe element from a superconducting quantum inference device magnetometer measurement. Furthermore, the characteristic iron L 2 and L 3 absorption edge was analyzed by using electron energy loss spectrum. Further calculations on the ratio of the integrated intensity counts, done on the L 3 and L 2 absorption edge of iron, correspond to valence state of +3 [4]. This suggests that Fe ions supplies an extra electron carrier and contributes the inherent magnetic properties based on the double-exchange mechanism.

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