An ecofriendly and robust strategy is developed to construct a self-supported monolithic electrode composed of N-doped carbon hybridized with bimetallic molybdenum-tungsten carbide (Mo x W 2−x C) to form composite nanowires for hydrogen evolution reaction (HER). The hybridization of Mo x W 2−x C with N-doped carbon enables effective regulation of the electrocatalytic performance of the composite nanowires, endowing abundant accessible active sites derived from N-doping and Mo x W 2−x C incorporation, outstanding conductivity resulting from the N-doped carbon matrix, and appropriate positioning of the d-band center with a thermodynamically favorable hydrogen adsorption free energy (ΔG H*) for efficient hydrogen evolution catalysis, which forms a binder-free 3D self-supported monolithic electrode with accessible nanopores, desirable chemical compositions and stable composite structure. By modulating the Mo/W ratio, the optimal Mo 1.33 W 0.67 C @ NC nanowires on carbon cloth achieve a low overpotential (at a geometric current density of 10 mA cm −2) of 115 and 108 mV and a small Tafel slope of 58.5 and 55.4 mV dec −1 in acidic and alkaline environments, respectively, which can maintain 40 h of stable performance, outperforming most of the reported metal-carbide-based HER electrocatalysts.

2D Layered meso-M/N-C/N-G nanocomposites with high specific surface area, homogeneous distribution of ultra-small M-N-C nanoparticles less than 5 nm, and mesopores with a size of ∼3.6 nm exhibit excellent electrocatalytic activity toward oxygen reduction reaction (ORR) in acidic and alkaline media.

We report the intense multiphoton upconversion of β-NaYF4: Yb3+–Tm3+ individual nanocrystals benefiting from the perfect ladder-type electron configuration under saturation excitation.

A universal strategy was developed for fabrication of a highly active and durable precious-metal-free mesoporous Mo2C/graphene (m-Mo2C/G) electrocatalyst with a two-dimensional layered structural feature via a nanocasting method using glucose as a carbon source and an in-stiu assembled mesoporous KIT-6/graphene (KIT-6/G) as a template. The m-Mo2C/G catalyst exhibits high catalytic activity and excellent durability for hydrogen evolution reaction (HER) over a wide pH range, which displays a small onset potential of 8 mV, owerpotential (η10) for driving a cathodic current density of 10 mA·cm(-2) of 135 mV, a Tafel slope of 58 mV·dec(-1), and an exchange current density of 6.31 × 10(-2) mA·cm(-2) in acidic media and an onset potential of of 41 mV, η10 of 128 mV, Tafel slope of 56 mV·dec(-1), and an exchange current density of 4.09 × 10(-2) mA·cm(-2) in alkaline media, respectively. Furthermore, such an m-Mo2C/G electrocatalyst also gives about 100% Faradaic yield and shows excellent durability during 3000 cycles of a long-term test, and the catalytic current remains stable over 20 h at fixed overpotentials, making it a great potential application prospect for energy issues.

A novel well-defined 0D/2D heterojunctions of uniform molybdenum carbide-tungsten carbide quantum dots/N-doped graphene nanosheets with high HER performance was synthesized by a “nanocasting” method.

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Developing high-performance but low-cost hydrogen evolution reaction (HER) electrocatalysts with superior activity and stability for future sustainable energy conversion technologies is highly desired. Tuning of microstructure, configuration, and chemical composition are paramount to developing effective non-noble electrocatalysts for HER. Herein, a universal "nanocasting" method is reported to construct graphene decorated with uniform ternary (CoP) -(FeP) (0 ≤ x ≤ 1) nanorods hybrids with different chemical compositions [(CoP) -(FeP) -NRs/G] as a highly active and durable nonprecious-metal electrocatalyst for the HER. The optimized (CoP) -(FeP) -NRs/G electrocatalyst exhibits overpotentials of as low as 57 and 97 mV at 10 mA cm , Tafel slopes of 52 and 62 mV dec , exchange current densities of 0.489 and 0.454 mA cm , and Faradaic efficiency of nearly 100% in acidic and alkaline media, respectively. More importantly, this electrocatalyst also exhibits high tolerance and durability in a wide pH range and keeps catalytic activity for at least 3000 cycles and 24 h of sustained hydrogen production. The excellent catalytic performance of the (CoP) -(FeP) -NRs/G electrocatalyst may be ascribed to its unique mesoporous structure and strong synergistic effect between CoP and FeP. Thus, the work provides a feasible way to fabricate cheap and highly efficient electrocatalyst as alternatives for Pt-based electrocatalysts for HER in electrochemical water splitting.

Hexagonal-phase NaYF 4 : Yb 3+ , Er 3+ nanoparticles (NPs) have been widely used as the most efficient NIR-to-visible upconversion (UC) luminescent and probe in bioscience. Here, we exploited not only the function of dual-mode emission of β-NaYF 4 : Yb 3+ , Er 3+ NPs in the near infrared (NIR) and visible regions with single wavelength excitation at 980 nm, but also the function of physiological temperature sensing with the luminescence of Er 3+ in the visible region. The structural and optical characteristics of β-NaYF 4 : Yb 3+ , Er 3+ NPs were obtained using X-ray diffraction (XRD), scanning electron microscopy (SEM),and fluorescence spectral measurements, respectively; the mechanism for the energy transfer has been suggested with emphasis on the optimized Er/Yb concentration for most efficient UC. Due to the UC and down-shifting NIR properties, we achieved the dual-functional nanoparticles with potential application in physiological range temperature sensing and bioimaging simultaneously.