Supported Heterostructured MoC/Mo₂C Nanoribbons and Nanoflowers as Highly Active Electrocatalysts for Hydrogen Evolution Reaction

Abstract

Development of low-cost and high-efficiency electrocatalysts for hydrogen evolution reaction is a critical step toward sustainable water splitting. Herein, in situ growth of heterostructured MoC/Mo2C nanoribbons and nanoflowers on copper foam (Mo x C/Cu), copper foil, and nickel foam (Mo x C/Ni) are prepared via a two-step method: hydrothermal preparation of molybdenum precursors followed by pyrolysis at controlled temperatures. The Mo x C/Cu hybrids are found to exhibit an excellent catalytic activity, as compared to the Mo x C/Ni and Cu foil counterparts, and the sample prepared at 750 °C stands out as the best among the series with a low overpotential of 169 mV to reach the current density of 200 mA cm–2 in 1 M KOH, and 194 mV in 0.5 M H2SO4, and the corresponding Tafel slopes of 98 and 74 mV dec–1, respectively. The electrocatalytic activity is also found to vary with the Mo2+/Mo3+ and N contents in the samples that impact the electrical conductivity and electron-transfer kinetics of the hydrogen evolution reaction. Results suggest that MoC/Mo2C heterostructured materials supported on copper foam may be a viable candidate to catalyze hydrogen evolution reaction in a wide range of pH.

Three-dimensional hierarchical MoO2/MoC@NC-CC free-standing anode applied in microbial fuel cells

“…2a, the high-resolution C 1s spectrum includes four distinct peaks located at 284.4 eV, 284.75 eV, 285.5 eV, and 286.7 eV, and they can be indexed to C–Mo, C–C/CC, C–N, and CO, respectively. 39,40 The appearance of the C–N peak further confirms the successful doping of the N element in the carbon skeleton. 41 For the O 1s spectrum (Fig.…”

Core–Shell Co, Zn Bimetallic Selenide Embedded Nitrogen-Doped Carbon Polyhedral Frameworks Assist in Sodium-Ion Battery Ultralong Cycle

“…35 The C 1s spectrum in Figure 5f shows peaks at 284.6, 285.5, and 287.9 eV, which can be ascribed to the C−C, C−N, and CO bonds, respectively. 31,39 The sodium storage performance of the as-prepared material was evaluated by assembling a coin battery. Figures S4a,b and 6a show the first three cycles of the cyclic voltammograms (CV) of ZnSe/NC, CoSe 2 /NC, and ZnSe@CoSe 2 /NC electrodes at voltages of 0.01−2.5 V at a scan rate of 0.1 mV s −1 .…”

Transition‐Metal Carbides as Hydrogen Evolution Reduction Electrocatalysts: Synthetic Methods and Optimization Strategies

“…Besides carbon matrixes, transition‐metal compounds with well‐defined structures can be introduced to constitute heterostructures with TMCs. Based on the advantage of the synergistic effect between heterostructure components, which is conducive to the further improvement of catalytic performance, different kinds of those TMC‐containing heterostructures have been exploited for HER, such as, Mo 2 N‐Mo 2 C, [81] W x C@WS 2 , [82] MoC‐Mo 2 C, [15b, 83] MoO x ‐Mo 2 C, [84] etc.…”