Trimetallic Mo-/Ni-/Fe-Based Hybrids Anchored on Hierarchical N-CNTs Arrays with Abundant Defects and Interfaces for Alkaline Water Splitting

Abstract

The intrinsic catalytic activity of cost-effective non-noble transition-metal-based electrocatalysts greatly limits their overall water splitting efficiency. In this work, Mo-/Ni-/Fe-based ternary transition-metal composites are uniformly anchored on the hierarchical nitrogen-doped carbon nanotubes (N-CNTs)/carbon cloth (CC) via a one-pot hydrothermal process, followed by hydrogenation and sulfurization to obtain the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) electrocatalysts, respectively. The rationally designed hybrids with various crystalline structures, heteroatom dopants, and large accessible surface areas can form abundant heterojunction interfaces and rich active defects to adjust the local electronic structure and intrinsic electrocatalytic capability. Therefore, the H-MoNiFe/N-CNTs-2 electrode reveals a low OER overpotential of 259.0 mV at 50 mA cm −2 and a small Tafel slope of 44.3 mV dec −1 , while the S-MoNiFe/N-CNTs-1 electrode exhibits a good HER overpotential of 130.7 mV at 10 mA cm −2 . Moreover, the electrolysis device exhibits a low cell voltage of 1.58 V at 10 mA cm −2 and maintains excellent catalytic activity under a high current for 12 h. This work provides a simple but rational composite electrode construction strategy with broad application prospects for electrocatalytic reactions.

Interface Engineering of MOF-Derived NiMoO4@NiFeP Core–Shell Nanorods for Energy-Saving Hydrogen Evolution via Urea Electrolysis

“…To achieve highly efficient multifunctional electrocatalysts, significantly exposed active sites, desired heterostructure and composition, as well as optimized surface/interface properties, are quite vital. 38 Transition metal phosphides (TMPs) have been regarded as promising electrocatalysts for alkaline HER because the electronegative P atom in TMPs can act as the site to trap H* and weaken the bonds between metal and hydride. Specifically, by doping other transition metal atoms to generate bimetallic phosphides (BMPs), boosted HER performance is demonstrated.…”

“…The design of multifunctional electrocatalysts is not simply integrating different monofunctional materials in one electrocatalyst. To achieve highly efficient multifunctional electrocatalysts, significantly exposed active sites, desired heterostructure and composition, as well as optimized surface/interface properties, are quite vital …”

One-Step Electrodeposition of NiMoP/NF as an Efficient and Cost-Effective Cathodic Electrocatalyst for Alkaline Water Electrolysis

“…Although many studies have been conducted on decreasing the doping amount of rare and precious metals like Pt, Pd, and Ir, and the properties of these materials also have shown excellent performance, − the nonrenewable and scarce precious metals are still difficult to produce and use on a large scale. Transition metals, such as Ni, Mo, Fe, Co, and so on, have rich content, the alloy formed by each other, − and the transition metal-based compounds formed with P, B, S, N, and other elements have excellent electrolytic water hydrogen evolution performance − and will eventually become a substitute for precious metals . Among the transition metal-based compounds, numerous studies have proved that transition metal-based phosphates (TMPs) have excellent activity, abundant active sites, and long-term stability .…”

Plasma-Induced Surface Reconstruction of NiFe/Co3O4 Nanoarrays for High-Current and Ultrastable Oxygen Evolution and the Urea Oxidation Reaction

“…As the depletion of fossil fuels and environmental pollution are becoming more prominent, sustainable energy is highly demanded. , Hydrogen energy is clean and renewable with high energy density, which is considered as a substitution to solve environmental and energy crises. − Electrochemical water splitting is the most feasible and efficient method for hydrogen production, especially when coupled with renewable sources to store intermittent energy. , As a half-reaction, the oxygen evolution reaction (OER) is a four-electron multistep process, which shows sluggish reaction kinetics and high equilibrium potential. , In addition, oxygen produced from water electrolysis is considered as a low-value product compared with hydrogen. Therefore, the anodic process is considered to be the limiting step in water splitting, which hinders practical hydrogen production. , Urea is widely distributed in agricultural/industrial/domestic wastewater, which leads to eutrophication and causes environmental pollution.…”