Bifunctional water splitting enhancement by manipulating Mo-H bonding energy of transition Metal-Mo2C heterostructure catalysts

CoW Bimetallic Carbide Nanocatalysts: Computational Exploration, Confined Disassembly–Assembly Synthesis and Alkaline/Seawater Hydrogen Evolution

“…The optimized ΔG H* of H* on Co 6 W 6 C leads to the moderate metal-H bond and the favorable H adsorption, and the accelerated subsequent Heyrovsky step in HER. [40] After the introduction of late transition metal Co atoms, a "3d electron complementary effect" could be achieved in Co 6 W 6 C. According to the DFT calculation results, the interaction between Co and W species could lead to the electronic structure redistribution of CoW bimetallic carbide, and thus, the improved electrical conductivity and optimized adsorption/desorption of *H intermediate. These improvements are responsible for the following dissociation energy reduction of absorbed H 2 O molecules from the catalyst surface and the resultant HER catalytic activity enhancement of CoW bimetallic carbide.…”

In situ phase transition induced TM–MoC/Mo2C (TM= Fe, Co, Ni, and Cu) heterostructure catalysts for efficient hydrogen evolution

“…3,4 Therefore, the development of nonnoble-metal-based electrocatalysts with long-term stability and high activity is indispensable for practical hydrogen production. 5 As alternatives to noble-metal catalysts, Mo-based electrocatalysts, such as Mo 2 C, [6][7][8][9][10] MoS 2 , [11][12][13][14][15] MoN, [16][17][18] and MoP, [19][20][21] have attracted great attention for the HER, due to their long-term stability in the HER. For example, Wan et al 22 synthesized molybdenum carbides in different phases, such as a-MoC 1Àx , b-Mo 2 C, h-MoC, and g-MoC, and compared their activities for the HER, in which b-Mo 2 C demonstrated the highest catalytic activity.…”

“…As alternatives to noble-metal catalysts, Mo-based electrocatalysts, such as Mo 2 C, 6–10 MoS 2 , 11–15 MoN, 16–18 and MoP, 19–21 have attracted great attention for the HER, due to their long-term stability in the HER. For example, Wan et al 22 synthesized molybdenum carbides in different phases, such as α-MoC 1− x , β-Mo 2 C, η-MoC, and γ-MoC, and compared their activities for the HER, in which β-Mo 2 C demonstrated the highest catalytic activity.…”

Graphite Nanoflake-Modified Mo2C with Ameliorated Interfacial Interaction as an Electrocatalyst for Hydrogen Evolution Reaction

“…Molybdenum carbide (Mo 2 C) is anticipated for not only the abundant molybdenum resources but also the fantastic stability and convenient synthetic process, cutting a fabulous figure in mass production for electrocatalytic water splitting among multifarious candidates. − More importantly, as a typical metallic interstitial compound, the d-orbitals of molybdenum hybridize with vacancies in carbon orbitals, leading to the decrease of the d-orbital width of molybdenum, making Mo 2 C a Pt-like electrocatalyst to adsorb hydrogen atoms. − However, bulk Mo 2 C exhibited some deficient properties as an electrocatalyst for the HER such as the strong Mo–H bond caused by the large unoccupied d-orbitals of Mo in Mo 2 C, which prohibited the desorption of the adsorbed H (H ads ), leading to suppressed activity through the overall electrocatalytic water splitting process. , In addition, the HER activity of Mo 2 C is simultaneously impacted by the insufficiently exposed active sites caused by the sintering during the carburizing process at high temperatures (>1000 °C). ,, The abovementioned issues can be addressed by means of surface and interface engineering, including the increased number of active sites by decreasing the particle size or introducing porous or hierarchical structures and surface modification by introducing heteroatom(s), defects, carbon materials, and other electronic conductive species, so as to prevent the aggregation of formed Mo 2 C nanoparticles, expose active sites, increase the electrical conductivity, and tune the electronic structure . For example, ultrasmall Mo 2 C nanocrystals anchored on honeycomb-structured N-doped carbon spheres, in which nanosized Mo 2 C was stabilized on a conductive carbon matrix with high porosity and a large surface area, exhibited a good HER catalytic activity in alkaline media with an overpotential of 128 mV at 10 mV cm –2 and a Tafel slope of 60 mV dec –1 .…”