Nanocrystalline Mo₂C as a Bifunctional Water Splitting Electrocatalyst

Abstract

Mo2C is a well‐known low cost catalyst for the hydrogen evolution reaction (HER), but the other water splitting half reaction, the oxygen evolution reaction (OER), has not been previously reported. To investigate both reactions and the origin of the catalytic sites, four synthesis methods were employed to prepare hexagonal Fe2N type Mo2C. A comparison of the HER activities in acidic and alkaline electrolyte and OER activities in alkaline electrolyte revealed that changes in synthesis route leads to morphological and surface composition variations resulting in different catalytic activities. In general, the trend in HER and OER activities show remarkably similar trends across the carbides synthesized via different routes irrespective of either electrolyte employed or reaction probed for electrocatalytic activities. Mo2C templated on multiwalled carbon nanotubes demonstrated the highest bifunctional catalytic activities, as well as superior electrochemical stability for both HER and OER.

Ni Strongly Coupled with Mo2C Encapsulated in Nitrogen‐Doped Carbon Nanofibers as Robust Bifunctional Catalyst for Overall Water Splitting

“…Nevertheless, Ni nanoparticles are prone to aggregation under typical HER and OER conditions, such as strong acid and alkali, and are prone to be corroded and passivated. [38][39][40][41][42] For instance, Kwak et al has successfully prepared Mo 2 C/carbon nanotube composites as bifunctional catalysts for both ORR and OER. [24][25][26][27] Among them, molybdenum carbide (Mo 2 C) is interesting due to its innocuous preparation process, large pH stability, and equivalent d-band electronic structure to Pt-group metals, [28][29][30][31] demonstrating a It is urgently required to develop highly efficient and stable bifunctional non-noble metal electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for water splitting.…”

An Intriguing Pea‐Like Nanostructure of Cobalt Phosphide on Molybdenum Carbide Incorporated Nitrogen‐Doped Carbon Nanosheets for Efficient Electrochemical Water Splitting

“…The XPS results for CoP-Mo 2 C@NC/CC suggest the formation of CoÀPb ecause Co 2p 3/2 and Co 2p 1/2 peaks appear at 778.8 and 793.8 eV,r espectively. [13,14] In addition, the presence of Co 2 + species in the materiali sa lso confirmed from the XPS study. [36] Shake-up satellites are found at 786.4 and 802.8 eV for the two doublets: Co 2p 3/2 and Co 2p 1/2 ,r espectively.T he deconvoluted Mo 3d XPS profile represents the assigned peaks of Mo 2 Ca t2 28.4/231.5 eV andm olybdenum oxide at 232.5/ 235.6 eV for Mo 3d 5/2/ Mo 3d 3/2 (Figure 2c).…”

“…[13,14] In addition, the presence of Co 2 + species in the materiali sa lso confirmed from the XPS study. [13,14] In addition, the presence of Co 2 + species in the materiali sa lso confirmed from the XPS study.…”

“…[3][4][5] Among the family of metal carbides, molybdenumc arbide (Mo 2 C) is one of the best HER catalysts because the introduction of carbon into the interstitial position of molybdenum leads to modified d-band structures, similart ot hose of platinum, and its corrosion-resistance properties are expectedt ol ead to significant durability of the electrocatalyst. [13,14] On the other hand, metallic phosphides, and specifically cobalt phosphide (CoP), have af avorable hydrogen bindinge nergy (DE H* ), which is an important parameter for good HER performance. [13,14] On the other hand, metallic phosphides, and specifically cobalt phosphide (CoP), have af avorable hydrogen bindinge nergy (DE H* ), which is an important parameter for good HER performance.…”

“…[6][7][8][9][10][11][12] However,r eports on stable, full water splitting by molybdenum carbides are limited. [13,14] On the other hand, metallic phosphides, and specifically cobalt phosphide (CoP), have af avorable hydrogen bindinge nergy (DE H* ), which is an important parameter for good HER performance. [15][16][17][18][19] In addition, transition-metal phosphidesa lso perform reasonably well towards the OER in alkaline media, possibly because of the formation of OER-active metal oxyhydroxides.…”