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An efficient electrocatalyst of molybdenum carbide nanodots on carbon nanosheets (nano-MoC/C-Ns) is prepared via a novel interlayer-confined strategy with the aid of MCM-22(P), a kind of multilayered two-dimensional (2D) zeolite precursor. In this strategy, the confined space of the surfactant-swollen MCM-22(P) plays a critical role in creating a unique sandwich-like structure with Mo-based organic–inorganic nanohybrids which further in situ evolve into ultrafine ∼2 nm MoC nanodots on carbon nanosheets in the following carbonization process. After etching the zeolite layers, the nano-MoC/C-Ns is successfully obtained as an efficient noble-metal-free electrocatalyst for hydrogen evolution. The intimate contact between ultrafine MoC nanodots and C nanosheets, as well as their synergetic effects, endows this catalyst with large exposed active sites and accelerated electron transport. The optimal sample achieves excellent hydrogen evolution reaction performance in acidic, neutral and alkaline media with low η10 values of 126, 185 and 92 mV (vs. the values of 28, 36 and 37 mV for a Pt/C reference in acidic, neutral and alkaline media), respectively. This synthetic strategy provides some hints for designing high-performance carbides for energy conversion and storage. [ABSTRACT FROM AUTHOR]

Molybdenum carbides (MoxC) are regarded as low-cost non-noble metal electrocatalysts for the hydrogen evolution reaction (HER). However, most reported powdery MoxC materials suffer from several drawbacks of polymer binders (such as Nafion) including partial blocking of active sites and decreased long-term stability. The recently developed binder-free MoxC materials are based on pre-treated commercial current-collecting substrates such as carbon cloth and carbon fibers, which make it basically impossible to design hierarchical porosity and achieve uniform distribution of active sites. Herein, we successfully synthesized self-supporting binder-free Mo2C composited electrocatalytic materials by integrating Mo2C nanoparticles with three-dimensional (3D) hierarchical porous carbon monoliths (PCMs) via a facile impregnation followed by in situ carbonization treatment (denoted as 3D Mo2C/PCM). As a result, Mo2C nanoparticles of ∼5 nm were uniformly distributed on the in situ transformed carbon matrix, and their uniform macropores (∼9 μm) and open ordered mesopores (5.6 nm) guaranteed fast mass transport and full exposure of active sites. The optimal 3D Mo2C/PCM sample displayed overpotentials of 81 and 47 mV at 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH, respectively, and the corresponding Tafel slopes were 63 and 45 mV dec−1. Benefiting from the outstanding mechanical strength and the easy-to-adjust macromorphology, 3D Mo2C/PCM could be directly used as a self-supporting working electrode without adding any binders. The synthesis strategy in this work may be extended to fabricate other bulky self-supporting carbon-based catalysts. [ABSTRACT FROM AUTHOR]

A simple one-step hydrothermal route is developed to synthesize one-dimensional (1D) hexagonal tungsten bronze (HTB) nanostructures. The key to this route is utilizing the electrostatic attraction between negatively charged tungstate and protonated ethylenediamine (EDA) to create a special local reductive environment in a non-reductive aqueous solution, which contributes to the in situ reduction of some of the hexavalent tungsten atoms during the 1D growth process and the mixed-valent nature of the final HTB structure. The as-prepared HTB nanomaterials are characterized to be highly crystalline and of uniform 1D morphology. Influences of synthetic conditions, such as the pH value, reaction time, temperature and amount of EDA, are systematically investigated. Meanwhile, this strategy is successfully introduced to prepare a series of metal-doped 1D HTB nanomaterials by simply changing the type of starting alkali tungstate. Experimental evidence reveals that the formation of the products follows an electrostatic-induced reductive nucleation–dissolution–recrystallization process, and the electrostatic interaction between the two oppositely charged species plays an indispensable role in the growth of mixed-valent HTB nanostructures. More importantly, these nanomaterials show efficient transformation of near-infrared light into local heat, indicating their potential applications as a new genre of functional materials in photothermal energy conversion as well as other relevant criteria. [ABSTRACT FROM AUTHOR]

An effective and safe route is proposed to prepare supported Mo2C-based catalysts from organic–inorganic hybrids, which exhibit high activity and stability for producing H2from methanol catalytic decomposition. [ABSTRACT FROM AUTHOR]

An effective and safe route is proposed to prepare supported Mo2C-based catalysts from organic–inorganic hybrids, which exhibit high activity and stability for producing H2from methanol catalytic decomposition. [ABSTRACT FROM AUTHOR]

Exploring efficient noble-metal free electrocatalysts for the hydrogen evolution reaction (HER) is one of the most promising pathways for facing the energy crisis. Herein, MoC-Mo 2 C heteronanowires composed of well-defined nanoparticles were accomplished via controlled carbonization, showing excellent HER activity, fast kinetic metrics and outstanding stability in both acid and basic electrolytes. In particular, the optimal one consisting of 31.4 wt% MoC displayed a low overpotential ( η 10 = 126 and 120 mV for reaching a current density of -10 mA cm -2 ), a small Tafel slope (43 and 42 mV dec -1 ) and a low onset overpotential (38 and 33 mV) in 0.5 M H 2 SO 4 and 1.0 M KOH, respectively. Such prominent performance, outperforming most of the current noble-metal free electrocatalysts, was ascribed to the carbide surface with an optimized electron density, and the consequently facilitated HER kinetics. This work elucidates a feasible way toward efficient electrocatalysts via heteronanostructure engineering, shedding some light on the exploration and optimization of catalysts in energy chemistry.

Novel Fe-MoO(x)/polyaniline nanorods were fabricated via in situ polymerization of Mo(3)O(10)(C(6)H(5)NH(3))(2)·2H(2)O nanowires, in which interface reactions remarkably influenced the morphology of products; and the nanorods showed high performance in cyclooctene epoxidation due to the organic-inorganic hybrid structure and Fe(3+) additive., (This journal is © The Royal Society of Chemistry 2012)

An effective and safe route is proposed to prepare supported Mo(2)C-based catalysts from organic-inorganic hybrids, which exhibit high activity and stability for producing H(2) from methanol catalytic decomposition.