Hierarchical NbS₂/MoS₂-Carbon Nanofiber Electrode for Highly Efficient and Stable Hydrogen Evolution Reaction at All Ranges of pH

Abstract

There is an urgent need to develop efficient and nonprecious electrode materials for practical electrocatalyst hydrogen evolution reaction (HER) application to restrain the depletion of fossil fuels. In the present work, we report an efficient and cost-effective electrode with high stability for binder-free water electrolysis under all ranges of pH from 0 to 14. Herein, a two-dimensional (2D) heterostructure of NbS2/MoS2 ultrathin vertical nanosheets was grown on carbon nanofiber with a high aspect ratio by the one-step chemical vapor deposition approach. The resultant hybrid catalyst demonstrates superlative HER performance with a small onset potential (41 mV @ ∼ 0 pH, 22 mV @ ∼ 7 pH and 32 mV @ ∼ 14 pH) and a very low overpotential (0.23 V @ ∼ 0 pH, 0.21 V @ ∼ 7 pH and 0.33 V @ ∼ 14 pH to reach 50 mA/cm2) vs reversible hydrogen electrode (RHE). Besides, the fabricated NbS2/MoS2-CNF displays excellent chronoamperometry stability for more than 50 h in all pH ranges. The proposed heterostructure holds the vital prerequisites for being a significant electrode material owing to multiple HER active edge and planar sulfur sites, excellent barrier-free charge transfer ability toward the electrolyte, and impressive endurance. Overall, the 2D/one-dimensional (1D) hybrid heterostructure appeared to be a precious-metal-free flexible electrode for excellent HER performance under wide ranges of pH for water splitting applications.

Developments and Perspectives on Robust Nano‐ and Microstructured Binder‐Free Electrodes for Bifunctional Water Electrolysis and Beyond

“…These characteristics provide efficient mass and electron transport to enhance electrocatalytic activity. [ 213,228–237 ] Wang et al. [ 228 ] prepared PtNi nanoparticles (NPs) immobilized on 3D CNF mats (PtNi/CNFs) using an electrospinning method and followed by carbonization.…”

“…Recently, Kulandaivel et al. [ 230 ] demonstrated the growth of 2D NbS 2 /MoS 2 ultrathin vertical nanosheets on CNFs with a high aspect ratio by a CVD approach, as shown in Figure 19ii. The designed heterostructure served as a viable electrocatalyst due to the presence of active edges and sulfur sites, which act in accelerating charge transfer towards the electrolyte.…”

“…These characteristics provide efficient mass and electron transport to enhance electrocatalytic activity. [213,[228][229][230][231][232][233][234][235][236][237] Wang et al [228] prepared PtNi nanoparticles (NPs) immobilized on 3D CNF mats (PtNi/CNFs) using an electrospinning method and followed by carbonization. CNFs provide distinctive advantages as a support material, including removing the need for polymer binders and providing a strong interaction between the NPs and CNFs.…”

“…[233] The unique hierarchical architecture of the binder-free electrode of CoNC@MoS 2 /CNF imparted favorable flexibility and sufficient electrical conductivity for electrochemical reactions. Recently, Kulandaivel et al [230] demonstrated the growth of 2D NbS 2 /MoS 2 ultrathin vertical nanosheets on CNFs with a high aspect ratio by a CVD approach, as shown in Figure 19ii. The designed heterostructure served as a viable electrocatalyst due to the presence of active edges and sulfur sites, which act in accelerating charge transfer towards the electrolyte.…”

Carbon Nanofibers Featuring Bimetallic Nanoparticle-in-Pore Structures as Water-Splitting Electrocatalysts

“…Nanostructured carbon materials have demonstrated significant potential for use in various innovative applications, particularly those in the area of energy storage and conversion. − Carbon materials are beneficial due to their excellent chemical inertness, electrical conductivity, and dimensional stability. − Furthermore, these carbon materials can take on additional functionalities. Methodologies for the functionalization of carbon materials with foreign atoms, molecules, or particulates include doping, precursor pyrolysis, physical deposition, and wet chemical deposition. − As a typical example, metal-decorated carbon materials have been obtained by mixing metal–precursor solutions with polymer–precursor solutions or carbon matrices/supports followed by the transformation of the precursor into a metallic phase via thermal or chemical reduction. − The distinctive properties of both the metal and carbon phases can be combined to give a hybrid material that exhibits outstanding catalytic and electrochemical performances. − Therefore, the introduction of metal-based components to carbon materials has made these materials a more attractive option for environment and energy applications. Various attempts have been made to achieve enhanced performances in such applications; however, the ability to precisely control the size, morphology, and loading amount of the metallic components being introduced into the carbon matrix remains elusive. − …”