Hierarchical Nanoboxes Composed of Co₉S₈−MoS₂ Nanosheets as Efficient Electrocatalysts for the Hydrogen Evolution Reaction

Abstract

The development of hydrogen evolution catalysts based on nonprecious metals is essential for the practical application of water-splitting devices. Herein, the synthesis of Co S -MoS hierarchical nanoboxes (HNBs) as efficient catalysts for the hydrogen evolution reaction (HER) is reported. The surface of the hollow cubic structure was organized by CoMoS nanosheets formed through the reaction of MoS and Co released from the cobalt zeolite imidazole framework (ZIF-67) templates under reflux in a mixture of water/ethanol. The formation process for the CoMoS HNB structures was characterized by TEM images recorded at various reaction temperatures. The amorphous CoMoS HNBs were converted through sequential heat treatments into CoS -MoS and Co S -MoS HNBs. Owing to their unique chemical compositions and structural features, Co S -MoS HNBs have a high specific surface area (124.6 m g ) and superior electrocatalytic performances for the HER. The Co S -MoS HNBs exhibit a low overpotential (η ) of 106 mV, a low Tafel slope of 51.8 mV dec , and long-term stability in an acidic medium. The electrocatalytic activity of Co S -MoS HNBs is superior to that of recently reported values, and these HNBs prove to be promising candidates for the HER.

Nitrogen and Sulfur Co‐Doped Mesoporous Carbon Embedded with Co9S8 Nanoparticles: Efficient Electrocatalysts for Hydrogen Evolution

“…To tackle these issues, non‐noble metal contained materials have received considerable researches . Among all of the catalysts, numerous efforts have been focused on Co 9 S 8 ‐based composites, which are proved to reveal superior electrocatalytic performance for HER …”

Electrochemical Energy Conversion and Storage with Zeolitic Imidazolate Framework Derived Materials: A Perspective

“…Although cobalt sulfides possess high electrical conductivity, it suffers from inferior stability during electrocatalysis. Various materials such as carbon, MoS 2 , and Fe have been incorporated to improve its activity and stability . Inspired by a good HER performance and chemical stability from MoS 2 , it has become an ideal candidate to couple with well‐defined polyhedral cobalt sulfides.…”

Hierarchical Cobalt Sulfide/Molybdenum Sulfide Heterostructure as Bifunctional Electrocatalyst towards Overall Water Splitting

“…In another example, Ganesan et al. proved synergistic effect between Co 9 S 8 and MoS 2 towards HER catalysis in alkaline medium . On the other hand, Co‐atoms at the interfaces of cobalt sulfide is responsible for OER catalytic activity .…”

“…The enhancement of HER catalytic activity in case of C 2 M 1 S could be attributed to the increment in number of active sites due to its well‐organized structure. The good electronic interaction between CoS x and MoS 2 via bridging S‐atoms helped in better charge transfer and facilitated substrate adsorption‐desorption kinetics . However, when robust structure got disrupted i. e., in the case of C 3 M 1 S, the catalytic efficiency got deteriorated.…”

“…[20] In another example, Ganesan et al proved synergistic effect between Co 9 S 8 and MoS 2 towards HER catalysis in alkaline medium. [21] On the other hand, Co-atoms at the interfaces of cobalt sulfide is responsible for OER catalytic activity. [22] Zhu et al established that the activity towards both HER and OER increased synergistically in the composite of Co 9 S 8 and MoS 2 as compared to their individual constituent.…”