A new family of transition‐metal monosilicides (MSi, M = Ti, Mn, Fe, Ru, Ni, Pd, Co, and Rh) electrocatalysts with superior electrocatalytic performance of hydrogen evolution is reported, based on the computational and experimental results. It is proposed that these MSi can be synthesized within several minutes by adopting the arc‐melting method. The previously reported RuSi is not only fabricated more readily but eventually explored 8 MSi that can be good hydrogen evolution reaction catalysts. Silicides then can be another promising electrocatalysts family as carbides, wherein carbon has the same electronic configuration as silicon. All explored silicides electrodes exhibited low overpotentials (34–54 mV at 10 mA cm−2) with Tafel slopes from 23.6 to 32.3 mV dec−1, which are comparable to that of the commercial 20 wt% Pt/C (37 mV, 26.1 mV dec−1). First‐principles calculations demonstrated that the superior performance can be attributed to the high catalytic reactivity per site that can even function at high hydrogen coverages (≈100%) on multiple low surface energy facets. The work sheds light on a new class of electrocatalysts for hydrogen evolution, with earth‐abundant and inexpensive silicon‐based compounds.

Transition metal dichalcogenides (TMDC's) usually exhibit layered polytypic structures due to the weak interlayer coupling. 2H-NbSe2 is one of the most widely studied in the pristine TMDC family due to its high superconducting transition temperature (Tc = 7.3K) and the occurrence of a charge-density wave (CDW) order below 33 K. The coexistence of CDW with superconductivity poses an intriguing open question about the relationship between Fermi surface nesting and Cooperpairing. Past studies of this issue have mostly been focused on doping 2H-NbSe2 by 3d transition metals without significantly changing its crystal structure. Here we replaced the Se by Te in 2H-NbSe2 in order to design a new 1T polytype layered TMDC NbSeTe, which adopts a trigonal structure with space group P3 ̅ m1. We successfully grew large size and high-quality single crystals of 1T-NbSeTe via the vapor transport method using I2 as the transport agent. Temperature-dependent resistivity and specific heat data revealed a bulk Tc at 1.3 K, which is the first observation of superconductivity in pure 1T-NbSeTe phase. This compound enlarged the family of superconducting TMDC's and provides an opportunity to study the interplay between CDW and superconductivity in the trigonal structure.

We report a systematic investigation on the evolution of the structural and physical properties, including the charge density wave (CDW) and superconductivity of the polycrystalline CuIr2Te4−x I x for 0.0 ≤ x ≤ 1.0. X-ray diffraction results indicate that both of a and c lattice parameters increase linearly when 0.0 ≤ x ≤ 1.0. The resistivity measurements indicate that the CDW is destabilized with slight x but reappears at x ≥ 0.9 with very high T CDW. Meanwhile, the superconducting transition temperature T c enhances as x increases and reaches a maximum value of around 2.95 K for the optimal composition CuIr2Te1.9I0.1 followed by a slight decrease with higher iodine doping content. The specific heat jump (ΔC/γT c) for the optimal composition CuIr2Te3.9I0.1 is approximately 1.46, which is close to the Bardeen–Cooper–Schrieffer value of 1.43, indicating that it is a bulk superconductor. The results of thermodynamic heat capacity measurements under different magnetic fields [C p(T, H)], magnetization M(T, H) and magneto-transport ρ(T, H) measurements further suggest that CuIr2Te4−x I x bulks are type-II superconductors. Finally, an electronic phase diagram for this CuIr2Te4−x I x system has been constructed. The present study provides a suitable material platform for further investigation of the interplay of the CDW and superconductivity.

We report the crystal structure, charge-density-wave (CDW), superconductivity (SC), and ferromagnetism (FM) in CuIr2-xCrxTe4 (0 ≤ x ≤ 2) chalcogenides. Powder x-ray diffraction (PXRD) results reveal that CuIr2-xCrxTe4 series are distinguished between two structural types and three different regions: (i) layered trigonal structure region, (ii) mixed phase regions, (iii) spinel structure region. Besides, Cr substitution for Ir site results in rich physical properties including the collapse of CDW, the formation of dome-shaped like SC, and the emergence of magnetism. Cr doping slightly elevates the superconducting critical temperature (Tsc) to its highest Tsc = 2.9 K around x = 0.06. As x increases from 0.3 to 0.4, the ferromagnetic Curie temperature (Tc) increases from 175 to 260 K. However, the Tc remains unchanged in the spinel range of 1.9 ≤ x ≤ 2. This finding provides a comprehensive material platform for investigating the interplay between CDW, SC, and FM multipartite quantum states.

Green and highly selective synthesis of organonitrogen chemicals (ONC) using renewable energy source of biomass over noble-metal free solid catalyst under common room temperature and pressure conditions is still a...