Trends in Electrochemical Stability of Transition Metal Carbides and Their Potential Use As Supports for Low-Cost Electrocatalysts

Kimmel, Yannick C.; Xu, Xiaoge; Yu, Weiting; Yang, Xiaodong; Chen, Jingguang G.

doi:10.1021/cs500182h

Cited by 150 publications

(172 citation statements)

References 31 publications

Supporting

Mentioning

168

Contrasting

Order By: Relevance

“…[1][2][3] In particular, tungsten carbide (WC) and molybdenum carbide (Mo 2 C) have been studied extensively for their catalytic similarities to the platinum group metals (PGMs). 4,5 Due to these favorable properties, TMCs have been identified as candidates for replacing expensive PGM catalysts in emerging renewable energy technologies, such as biomass conversion, fuel cells, and electrolyzers.…”

Section: Introductionmentioning

confidence: 99%

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

Hunt

Román‐Leshkov

2015

JoVE

View full text Add to dashboard Cite

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The silica-encapsulated metal oxide nanoparticles are then carburized in a methane/hydrogen atmosphere at temperatures over 800 °C to form silica-encapsulated early transition metal carbide nanoparticles. During the carburization process, the silica shells prevent the sintering of adjacent carbide nanoparticles while also preventing the deposition of excess surface carbon. Alternatively, the silica-encapsulated metal oxide nanoparticles can be nitridized in an ammonia atmosphere at temperatures over 800 °C to form silica-encapsulated early transition metal nitride nanoparticles. By adjusting the reverse microemulsion parameters, the thickness of the silica shells, and the carburization/nitridation conditions, the transition metal carbide or nitride nanoparticles can be tuned to various sizes, compositions, and crystal phases. After carburization or nitridation, the silica shells are then removed using either a room-temperature aqueous ammonium bifluoride solution or a 0.1 to 0.5 M NaOH solution at 40-60 °C. While the silica shells are dissolving, a high surface area support, such as carbon black, can be added to these solutions to obtain supported early transition metal carbide or nitride nanoparticles. If no high surface area support is added, then the nanoparticles can be stored as a nanodispersion or centrifuged to obtain a nanopowder. Video LinkThe video component of this article can be found at

show abstract

Section: Introductionmentioning

confidence: 99%

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

Hunt

Román‐Leshkov

2015

JoVE

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

“…The left-over porous CDC is metal free and sp 2 or sp 3 hybridized. 11,12 At room temperature, metal carbides are very stable in strong acidic solutions.…”

mentioning

confidence: 99%

“…However, when an electrical potential is applied, metal carbides can also be oxidized to form metal oxides. 3,13 In addition to the binary metal carbides, MAX phase metal carbides (Ti 3 AlC 2 , Ti 2 AlC and Ti 3 SiC 2 ) can be oxidized in acidic electrolyte solutions (HCl and HF) by electrochemical etching and yield CDC with uniformly distributed nanoscale pores. 14,15 In a previous report, binary metal carbides (VC and V 2 C) were electrochemically etched in acidic, neutral, or basic aqueous solutions and produced CDC materials that were excellent electrode materials for electronic double layer supercapacitors.…”

mentioning

confidence: 99%

“…Cyclic voltammetry and elemental analysis demonstrated that several carbides can be oxidized electrochemically at "mild" electrode potentials and produce soluble metal ions in the solutions. The remaining carbon atoms on the surface of the electrode after oxidation might be sp 3 or sp 2 hybridized, indicating the existence of the CDC structure. * Electrochemical Society Member.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Electrochemical Oxidation of Metal Carbides in Aqueous Solutions

Messner

Walczyk

Palazzo

et al. 2018

J. Electrochem. Soc.

View full text Add to dashboard Cite

Transition metal carbides have unique properties such as high hardness, high melting temperatures, high thermal conductivity, and high chemical stability. In this report, we investigate the electrochemical oxidation of a series of metal carbides including NbC, Nb 2 C, TaC, Ta 2 C, VC, VCrC, TiC and TiCrC in neutral, basic, or acidic aqueous solutions. Cyclic voltammetry and elemental analysis demonstrated that many of these metal carbides can be electrochemically oxidized at low electrode potentials to produce soluble metal ions in the solutions. Carbon in the metal carbides remains on the electrode substrates and forms porous carbide-derived carbon (CDC). The surface morphology of the CDC and specific surface area depend on the metal carbide precursors and the electrochemical oxidation conditions. © Transition metal carbides have extensive applications in many areas of the chemical and mechanical industries.1,2 For example, the refractory and hard ceramic material niobium carbides (NbC and Nb 2 C) have been broadly used as coatings for cutting tool bits and to improve wear resistance. Several transition metal carbides resemble the valence electron structures and the catalytic properties of metals such as Pt and Pd.2-5 The metal carbides or the Carbide-Derived Carbon (CDC) obtained from these metal carbide precursors can be used as supports to reduce the overall loading of the precious metals. 6,7 Pt nanoparticles demonstrate superior catalytic effects when they are loaded on WC or W 2 C powders for many reactions such as hydrogen oxidation, hydrogen evolution, alcohol oxidation, and oxygen reduction reactions. 8Due to their chemical stability and poor sintering ability, research on the chemical properties of the metal carbides is restricted to limited areas. 1,9 Metal carbides can be oxidized at higher temperatures with different oxidants. For example, NbC powder can be oxidized in an oxygen atmosphere at 420-600• C to produce Nb 2 O 5 . 10 At a temperature of 350• C or higher, most carbides can react with chlorine gas to form volatile metal chloride (MCl 4 ). The left-over porous CDC is metal free and sp 2 or sp 3 hybridized. 11,12 At room temperature, metal carbides are very stable in strong acidic solutions. However, when an electrical potential is applied, metal carbides can also be oxidized to form metal oxides. 3,13 In addition to the binary metal carbides, MAX phase metal carbides (Ti 3 AlC 2 , Ti 2 AlC and Ti 3 SiC 2 ) can be oxidized in acidic electrolyte solutions (HCl and HF) by electrochemical etching and yield CDC with uniformly distributed nanoscale pores.14,15 In a previous report, binary metal carbides (VC and V 2 C) were electrochemically etched in acidic, neutral, or basic aqueous solutions and produced CDC materials that were excellent electrode materials for electronic double layer supercapacitors. 16In this paper, we investigate the electrochemical properties of a series of metal carbides, NbC, Nb 2 C, TaC, Ta 2 C, VC, VCrC, TiC and TiCrC in aqueous solutions with the presence of HCl, HF, K...

show abstract

Transition Metal Carbides Electrocatalysts for Water Splitting

Leonard

2021

Encyclopedia of Inorganic and Bioinorganic Chemistry

View full text Add to dashboard Cite

Electrochemically splitting water into its two elemental components, hydrogen and oxygen, is being heavily investigated as a path toward renewable energy. Hydrogen has been viewed as an energy carrier which could store wind, solar, and other forms of renewable energy for later use. In order to develop the hydrogen economy, new stable, and economical water splitting catalysts need to be developed. Transition metal carbides (TMC) are robust materials consisting of only metal and carbon atoms. These compounds are electrically conducting, and resistant to degradation in conditions typical of electrochemical water splitting reactions. TMCs have been found to have an electronic structure that is similar to Pt and are being investigated as cost‐effective, stable materials for both hydrogen and oxygen reactions. These TMC catalysts have been modified using several approaches including forming nanoparticles to increase surface area, adding conducting carbon and doped carbon support materials, doping the metal carbide to alter the electronic structure, and creating heterointerfaces with other metals and compounds. Fundamental studies on the nitrogen (N‐doped) carbon composites have shown a significant synergistic effect by modifying the electronic structure and thus the hydrogen binding energy. The nitrogen sites also provide a unique and beneficial binding site for H atoms during the electrochemical process. The most challenging but promising area of study focuses on the combination of TMC compounds with another catalyst material to create optimized interfaces. These heterointerface materials are difficult to probe experimentally and further optimize but with advances in density‐functional theory (DFT) calculations, several predictive models have been established. Through these modifications, several catalyst systems have shown catalytic activity and stability that rivals precious metal catalysts at greatly reduced cost. In addition, some of the synthetic methods could be easily scaled for industrial applications. The future of TMC catalysts is extremely promising and with improvements in scalable synthesis methods, activity, and stability, these carbide catalysts will likely be utilized in commercial electrolysis applications.

show abstract

Trends in Electrochemical Stability of Transition Metal Carbides and Their Potential Use As Supports for Low-Cost Electrocatalysts

Cited by 150 publications

References 31 publications

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

Electrochemical Oxidation of Metal Carbides in Aqueous Solutions

Transition Metal Carbides Electrocatalysts for Water Splitting

Contact Info

Product

Resources

About