Doping with pyridinic nitrogen atoms is known as an effective strategy to improve the activity of carbon-based catalysts for the oxygen reduction reaction. However, pyridinic nitrogen atoms prefer to occupy at the edge or defect sites of carbon materials. Here, a carbon framework named as hydrogen-substituted graphdiyne provides a suitable carbon matrix for pyridinic nitrogen doping. In hydrogen-substituted graphdiyne, three of the carbon atoms in a benzene ring are bonded to hydrogen and serve as active sites, like the edge or defect positions of conventional carbon materials, on which pyridinic nitrogen can be selectively doped. The as-synthesized pyridinic nitrogen-doped hydrogen-substituted graphdiyne shows much better electrocatalytic performance for the oxygen reduction reaction than that of the commercial platinum-based catalyst in alkaline media and comparable activity in acidic media. Density functional theory calculations demonstrate that the pyridinic nitrogen-doped hydrogen-substituted graphdiyne is more effective than pyridinic nitrogen-doped graphene for oxygen reduction.

The new two-dimensional graphitic material, graphdiyne, has attracted great interest recently due to the superior intrinsic semiconductor properties. Here we investigate the magnetism of pure graphdiyne material and find it demonstrating a remarkable paramagnetic characteristic, which can be attributed to the appearance of special sp-hybridized carbon atoms. On this basis, we further introduce nitrogen with 5.29% N/C ratio into graphdiyne followed by simply annealing in a dopant source and realize a twofold enhancement of saturation moment at 2 K. Associate with the density of states calculation, we investigate the influence of the nitrogen atom doping sites on paramagnetism, and further reveal the important role of doped nitrogen atom on benzene ring in improving local magnetic moment. These results can not only help us deeply understand the intrinsic magnetism of graphdiyne, but also open an efficient way to improve magnetism of graphdiyne by hetero atom doping, like nitrogen doping, which may promote the potential application of graphdiyne in spintronics.

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On account of the high‐cost of platinum, researchers are working to develop a new catalyst that is cheaper and has a catalytic effect equivalent to platinum. Herein, owing to the unique acetylenic bonds in graphdiyne, iron, nitrogen co‐doped graphdiyne (Fe‐N‐GDY) is a promising nonprecious metal catalyst, which has been developed with just a small amount of iron precursor with the plan to substitute it for Pt‐based catalysts. The as‐synthesized Fe‐N‐GDY composited catalyst shows excellent catalytic performance with the onset potential of 0.94 V versus reversible hydrogen electrode and limited current density of 5.4 mA cm−2. Moreover, it shows excellent resistance to methanol poisoning and stability in both acidic and alkaline electrolytes, which makes potentially applicable in the oxygen reduction reaction field.

We report the magnetization, electrical resistivity, specific heat measurements and band structure calculations of layered superconductor SnTaS2. The experiments are performed on single crystals grown by chemical vapor transport method. The resistivity and magnetic susceptibility indicate that SnTaS2 is a type-II superconductor with transition temperature Tc = 3 K. The upper critical field (Hc2) shows large anisotropy for magnetic field parallel to ab plane (H//ab) and c axis (H//c). The temperature dependence of Hc2 for H//ab shows obvious upward feature at low temperature, which may originate from the multiband effect. Band structure of SnTaS2 shows several band crossings near the Fermi level, which form three nodal lines in the kz = 0 plane when spin-orbit coupling is not considered. Drumhead-like surface state from the nodal lines are clearly identified. These results indicate that SnTaS2 is a superconducting topological nodal line semimetal.