We prepare group VI transitional metal dichalcogenides (TMDs, or MX) from the 1T phase with quantum-sized and monolayer features via a quasi-full electrochemical process. The resulting two-dimensional (2D) MX (M = W, Mo; X = S, Se) quantum dots (QDs) are ca. 3.0-5.4 nm in size with a high 1T phase fraction of ca. 92%-97%. We attribute this to the high Li content intercalated in the 1T-MX lattice (mole ratio of Li:M is over 2:1), which is achieved by an increased lithiation driving force and a reduced electrochemical lithiation rate (0.001 A/g). The high Li content not only promotes the 2H → 1T phase transition but also generates significant inner stress that facilitates lattice breaking for MX crystals. Because of their high proportion of metallic 1T phase and sufficient active sites induced by the small lateral size, the 2D 1T-MoS QDs show excellent hydrogen evolution reactivity (with a typical η of 92 mV, Tafel slope of 44 mV/dec, and J of 4.16 × 10 A/cm). This electrochemical route toward 2D QDs might help boost the development of 2D materials in energy-related areas.

Graphene and MoS 2 were dispersed in Esterified Bio-Oil (EBO) and evaluated as lubricants for steel/steel contact. The tribological behaviors of steel/steel pairs were investigated under lubrication of graphene/MoS 2 blends with different mass ratios, loads and rotating speeds.The micro-morphologies of the worn surfaces were observed by optical and Scanning Electron Microscopy (SEM). The components of the additives and chemical valences of the elements on the rubbed surfaces were analyzed using Raman and X-ray Photoelectron Spectroscopy (XPS). A synergistic lubricating effect for both graphene and MoS 2 with contents of 0.5 wt.% as additives dispersed in EBO was observed that reduced the friction coefficient and wear of the steel specimens under boundary lubrication regime conditions. This was ascribed to the formation of a thicker adsorbed tribo film containing graphene, MoS 2 and organics from the EBO. Graphene was shown to improve the retention of MoS 2 on the frictional surfaces and prevent oxidation during rubbing.MoS 2 , on the other hand, prevented the graphene from being ground into small and defective platelets. Corresponding author. Tel/

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absorbers have aroused great attention due to their resonant absorption and localized heating effect. [7][8][9] Nevertheless, this resonant absorption inherently features a narrow bandwidth, which is usually advantageous for applications such as biosensors [10] and resonant energy transfer, [11] but disadvantageous for broadband light absorption. [12,13] Some complex and delicate plasmonic metastructures were thus designed to hybridize proximate surface plasmons [12] or to support multiple resonances [13] in order to broaden the absorption bandwidth. However, the noble metals (i.e., Au and Ag) for plasmonic absorption along with the complicated fabrication procedures are undesirable for large-scale and full-spectrum (300-2500 nm) solar energy harvesting. [14] Zhou et al. creatively fabricated an all-aluminum hybrid plasmonic membrane, which was lowcost and enabled efficient broadband solar absorption. [15] The broadband plasmonic absorber was based on closely packed Al nanoparticles along the side walls of nanopores to induce a plasmon hybridization effect and high-density plasmonic resonances. [15] Among the several mechanisms that cause light absorption in metals, [16] interband transitions (IBTs) are single-electron excitations [17] from occupied levels in one band to unoccupied levels in another band, [18] in contrast to the collectively coherent excitation of electrons for plasmonic absorption. [19] IBTs intrinsically have a broadband attribute because photons the energy of which surpasses the interband threshold of a metal can excite IBTs. This makes IBTs very suitable for full-spectrum solar energy utilization, especially when massive IBTs over the entire solar spectrum can be supported by some transition metals (e.g., Ni, Pd, and Pt) with a high density of electronic states (DOS) near their Fermi levels. [20][21][22] In this work, we designed a Ni-cellulose hybrid metamaterial (NCM) that employs IBTs as the dominant optical absorption mechanism over the entire solar spectrum (Figures S1 and S2, and Note S1 for the detailed demonstration, Supporting Information). Nickel supports strong IBTs in very low energy regions (≈0.5 eV), which greatly increase optical absorption in the near-infrared spectrum compared to plasmonic metals (Au, Ag, and Cu). We densely embedded Ni nanoparticles into the nanogaps of cellulose microfibers via a seed-mediated and nanoconfined growth. This nanoconfinement effect can inhibit Sophisticated metastructures are usually required to broaden the inherently narrowband plasmonic absorption of light for applications such as solar desalination, photodetection, and thermoelectrics. Here, nonresonant nickel nanoparticles (diameters < 20 nm) are embedded into cellulose microfibers via a nanoconfinement effect, producing an intrinsically broadband metamaterial with 97.1% solar-weighted absorption. Interband transitions rather than plasmonic resonance dominate the optical absorption throughout the solar spectrum due to a high density of electronic states near the Fermi level of nickel. Fiel...

Due to its fuel-efficient and environmentally friendly nature, the electrocatalytic nitrogen reduction reaction (NRR) has drawn significant attention.