One-Dimensional Porous Hybrid Structure of Mo₂C-CoP Encapsulated in N-Doped Carbon Derived from MOF: An Efficient Electrocatalyst for Hydrogen Evolution Reaction over the Entire pH Range

Abstract

The development of outstanding noble-metal-free electrocatalysts for the hydrogen evolution reaction (HER) has attracted broad interest. Herein, a novel one-dimensional (1D) HER hybrid catalyst consisted of cobalt phosphide (CoP) and molybdenum carbide (Mo2C) nanoparticles wrapped by nitrogen-doped graphitic carbon (called CoP/Mo2C-NC) was successfully fabricated by a facile continuous-flow method and a simple two-step annealing process. During these processes, the successful synthesis of the MoO3 nanorods coated with cobalt zeolitic imidazolate frameworks (Co-ZIF-67) (Co-ZIF-67@MoO3) through the continuous-flow method plays a key role. The as-synthesized CoP/Mo2C-NC hybrid electrocatalyst exhibits a significantly enhanced HER electrocatalytic activity over the entire pH range relative to that of the control materials CoP, Mo2C-NC, and physically mixed CoP and Mo2C-NC. The outstanding HER catalytic performance is mainly due to the fact that the electron cloud transfers from Co to Mo in CoP/Mo2C-NC through the Co–P–Mo bond, resulting in the formation of a high valence state for Co (Co3+) species and lower valence states for Mo (i.e., Mo2+, Mo3+) species, providing the abundant HER active sites. Moreover, the Gibbs free energy (ΔG H*) of CoP/Mo2C-NC obtained by the density function theory calculations indicates a good balance between the Volmer and Heyrovsky/Tafel steps in HER kinetics. Such a cobalt zeolitic imidazolate framework-mediated strategy depicted in this work offers an interesting perspective for developing highly efficient noble-metal-free electrocatalysts for hydrogen production.

Oriented Transformation of Co‐LDH into 2D/3D ZIF‐67 to Achieve Co–N–C Hybrids for Efficient Overall Water Splitting

“…Since the chemical and the physical properties of the MOFs‐derived TM‐carbon‐based nanohybrids are highly dependent on the MOF precursors, it has been widely acknowledged that building MOF precursors with favorable composition, morphology, and surface structure is a prerequisite to enable these nanohybrids with satisfactory electrocatalytic activity . To this end, there has been much attention surrounding the dedicate design of MOF precursors . Currently, most work basically focus on the 3D MOF precursors owing to their high structural stability, large specific surface areas, and abundant pores .…”

Surface and Interface Engineering: Molybdenum Carbide–Based Nanomaterials for Electrochemical Energy Conversion

“…Luo et al [ 204 ] synthesized a rod‐like electrocatalyst consisted of cobalt phosphide (CoP) and molybdenum carbide (Mo 2 C) nanoparticles wrapped by N‐doped graphitic carbon by a two‐step annealing method ( Figure a). As observed in Figure 12b,c, the lattice fringes with the d‐spacing of 0.23, 0.28, and 0.34 nm correspond to the (1 0 1) plane of β‐Mo 2 C, the (0 1 1) plane of CoP and the graphitic carbon, respectively.…”

Two‐Dimensional Nanosheet Structure of Co, S Co‐Doped Carbon‐Framework Supported MoO2 for Hydrogen Evolution Reaction in Alkaline Solutions

“…The carbon skeleton with homogeneous distribution can be easily obtained by metal organic framework (MOF). [7] The MOF is a new class of porous crystalline materials with unique octahedral configuration and high distribution. [8] After heat treatment, MOF material can transform into carbon-framework which is an ideal host material for MoO 2 catalyst.…”

“…Furthermore, the high conductivity of carbon‐framework can promote the electron transport greatly, which improves the HER performance. The carbon skeleton with homogeneous distribution can be easily obtained by metal organic framework (MOF) . The MOF is a new class of porous crystalline materials with unique octahedral configuration and high distribution .…”