In situ Engineering of Hollow Porous Mo2C@C Nanoballs Derived From Giant Mo-Polydopamine Clusters as Highly Efficient Electrocatalysts for Hydrogen Evolution

Abstract

Low-cost and highly effective catalysts are crucial to the electrocatalytic hydrogen evolution reaction (HER). Among non-noble catalysts, molybdenum carbides are promising candidates because of their high reserves, stability, low cost, and structural diversity. In this work, we report a simple method to fabricate a hollow porous Mo 2 C@C nanoball through a hydrothermal preparation process of molybdenum precursors at high temperatures. Specifically, we have combined interfacial polymerization and the chelation effect to synthesize the Mo-polydopamine (Mo-PDA) precursor. As a result, Mo 2 C@C-3 only requires an ultralow Tafel slope (∼55 mV dec −1) and low overpotential (η 50 ≈ 167 mV) in a 0.5 M H 2 SO 4 solution with long-term cycling stability. Besides, it also exhibits outstanding activity and stability under extensive HER testing in alkaline media. This study is promising for the development of advanced molybdenum carbide electrocatalysts toward electrochemical applications.

N-Doped Graphene-Decorated NiCo Alloy Coupled with Mesoporous NiCoMoO Nano-sheet Heterojunction for Enhanced Water Electrolysis Activity at High Current Density

“…To address this problem, some researchers reported a novel strategy to construct the 3D TMB catalysts with N-doped graphene-encapsulated to improve the stability and catalytic activity [ 15 ]. Deng et al prepared the ultrathin graphene layer encapsulating FeNi alloy and efficiently optimizing its surface electronic structure [ 16 ], and it obtains a low overpotential (280 mV) at 10 mA cm −2 for OER and can keep for 24 h. Mu et al fabricated a Mo 2 C@C nanoball with hollow porous, which displayed low overpotentials for HER in 1.0 M KOH (115 mV) and 0.5 M H 2 SO 4 (129 mV) solution at − 10 mA cm −2 [ 17 ]. Furthermore, other investigators also use the N-doped carbon-encapsulated 3D TMB catalysts, which can optimize the distribution of electrons on the metal surface and prevent metal dissolution under strong alkaline conditions to enhance the catalytic performance [ 18 – 20 ], while most of them are focusing on studying the catalytic performance at low current density and also need high potential to drive the WE.…”

Transition metal carbide‐based nanostructures for electrochemical hydrogen and oxygen evolution reactions

“…In addition, the hydrogen produced is of low purity due to the low conversion efficiency. Electrochemical water splitting is a promising and efficient technology for sustainable generation of hydrogen in its purest form 11,12 . Electrochemical water splitting involves the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER) (Figure 1).…”

“…Electrochemical water splitting is a promising and efficient technology for sustainable generation of hydrogen in its purest form. 11,12 Electrochemical water splitting involves the cathodic hydrogen evolution reaction (HER) and the anodic oxygen evolution reaction (OER) (Figure 1). The overall reaction for water splitting is given by the following equation:…”

Recent advances in Mo-based electrocatalysts toward the hydrogen evolution reaction and the hydrogen oxidation reaction

“…34 Nowadays, transition metals are regarded as substitutes for PGMs due to their high activity and low cost. 35,36 Molybdenum is a typical transition metal bearing the atomic number 42 with various oxidation states from II to VI. 37 It is well known that atomic doping could modify the electronic structure, promote the adsorption and evolution of hydrogen, and ultimately enhance the intrinsic activity of electrocatalysts.…”