Origami‐Inspired 3D Interconnected Molybdenum Carbide Nanoflakes

Abstract

COMMUNICATION (1 of 7)the energy requirements of the world. However, with the increase of population and development of technology, fossil fuels cannot serve as the primary energy source in the future due to the shortage of energy resources and a series of environment problems. As a result, renewable energy sources and their storage are becoming increasingly important. To solve this energy demand, it is necessary to develop new systems to improve the efficiency of energy conversion and storage. Development and design of new high-performance materials are the state-of-the-art of these systems. To improve them, new nonexpensive and efficient materials, such as metal sulfides, [1][2][3][4] carbides, [5][6][7][8] nitrides, [9,10] and phosphides, [11][12][13] have been explored. High-temperature stable (>1000 °C) transition metal carbides have great potential especially for catalysis and energy storage application due to their structural stability and high chemical activity. [5,[14][15][16][17][18] Recent reports have shown that metal carbides can replace classical expensive metal catalysts such as platinum. [19][20][21] Among all metal carbides, molybdenum carbide (Mo 2 C) possesses numerous valuable properties, particularly of excellent catalytic properties, such as high electronic conductivity as well as excellent thermal, mechanical, and chemical stability. [22] There are several material properties that play an important role on the efficiency of the catalyst such as the surface area, morphology, and the structure that can strongly affect its catalytic activity. For example, Tuomi et al. reported that the catalytic activity of molybdenum carbide is highly affected by the surface orientation. [23,24] In addition, molybdenum carbide-derived materials have also been studied in electrochemical applications such as Li-ion batteries and supercapacitors, due to its high theoretical capacity and capacitance. [22,[25][26][27] Recently, there has been much interest for creating origamilike structures in natural sciences, engineering, and architecture. Across these different fields, origami starts to inspire researchers for new reconfigurable and multifunctional materials and structures. However, the use of origami designs at the nanoscale is typically compromised by limitations in structural performance. If nanomaterials can be created in origami-like shapes, new multifunctional materials with improved surface area, mechanical properties, and performance in devices can be fabricated. Although metal carbides have exciting properties, High-temperature stable transition metal carbides are one of the promising classes of materials for next-generation energy applications such as water splitting catalysis and electrodes for energy storage devices. Herein, origami-like molybdenum carbide flakes with interfacially connected structures in various orientations using an easily scalable chemical vapor deposition method are synthesized. Interestingly, each individual flake of similar orientation is interconnected across different plane...

Mesoporous Carbon Nanotablets Coupled with Mo2C Nanoparticles: Combining Morphology and Structure to Realize High Activity for Efficient Hydrogen Evolution

“…The structure information was further obtained by Raman and N 2 ad‐/desorption analysis.As shown in Figure g, the peaks centred at 818 and 992 cm −1 for nanotablets material confirm the formation of Mo 2 C, and the broad shoulder peaks located at ca. 1350 cm −1 and 1590 cm −1 are magnified and displayed in inset of Figure g, which are matched to the D and G bands originated from the defective carbon and graphitic carbon, respectively . The intensity ratio of 0.89(I D /I G ) shows the high degree of graphitization in Mo 2 C/C nanotablets material.…”

“…1350 cm À 1 and 1590 cm À 1 are magnified and displayed in inset of Figure 1g, which are matched to the D and G bands originated from the defective carbon and graphitic carbon, respectively. [32,33] The intensity ratio of 0.89(I D / I G ) shows the high degree of graphitization in Mo 2 C/C nanotablets material. Itsmesoporous-structure characteristicis observed from N 2 ad/desorption curve ( Figure 1h) and the pore size distribution isin the range of 2-4 nm (inset in Figure 1h), indicating successful synthesis of mesoporous Mo 2 C material possessing hexagonaltablet morphology.…”

Metal (Mo, W, Ti) Carbide Catalysts: Synthesis and Application as Alternative Catalysts for Dry Reforming of Hydrocarbons—A Review

“…The structure-directing method of molybdenum carbide particle preparation may involve other groups of organic precursors such as dyes [114], saccharides [115,116], chelates [117], urea [118,119], metal-organic frameworks [120], polymers (polyaniline, polypyrrole) [121], and volatile organic compounds (VOCs) [122]. Recently, Gavrilova et al [123] reported a Mo 2 C preparation method via thermal decomposition of molybdenum blue nanoparticles.…”

“…In Table 6, selected methods for molybdenum carbide preparation using the structure-directing method are summarized. Koizumi et al [122] reported the synthesis of interconnected molybdenum carbide phase nanoflakes that form 3D origami-like structures. The methods for preparation of the structures involved chemical vapor deposition (CVD).…”

Balance Effect: A Universal Strategy for Transition Metal Carbides to Enhance Hydrogen Evolution

“…[14,15] TMCs also exhibit superior electrical conductivities and broader pH applicability when compared with TM oxides/sulfides/phosphides/nitrides. [16,17] In these regards, the kinetics of HER on the TMCs has been much boosted or the HER performance on the TMCs is outstanding (e.g., high catalytic activity and long-term stability). Unfortunately, the density of empty d-bands in most TMCs is high, results in the strong binding of a TMC electrocatalyst with hydrogen intermediate (H*).…”