Engineering Sulfur Vacancies in Spinel-Phase Co₃S₄ for Effective Electrocatalysis of the Oxygen Evolution Reaction

Abstract

Restricted by the sluggish kinetics of the oxygen evolution reaction (OER), efficient OER catalysis remains a challenge. Here, a facile strategy was proposed to prepare a hollow dodecahedron constructed by vacancy-rich spinel Co 3 S 4 nanoparticles in a self-generated H 2 S atmosphere of thiourea. The morphology, composition, and electronic structure, especially the sulfur vacancy, of the cobalt sulfides can be regulated by the dose of thiourea. Benefitting from the H 2 S atmosphere, the anion exchange process and vacancy introduction can be accomplished simultaneously. The resulting catalyst exhibits excellent catalytic activity for the OER with a low overpotential of 270 mV to reach a current density of 10 mA cm –2 and a small Tafel slope of 59 mV dec –1 . Combined with various characterizations and electrochemical tests, the as-proposed defect engineering method could delocalize cobalt neighboring electrons and expose more Co 2+ sites in spinel Co 3 S 4 , which lowers the charge transfer resistance and facilitates the formation of Co 3+ active sites during the preactivation process. This work paves a new way for the rational design of vacancy-enriched transition metal-based catalysts toward an efficient OER.

Strategies for Promoting Catalytic Performance of Ru‐Based Electrocatalysts towards Oxygen/Hydrogen Evolution Reaction

“…As well acknowledged, the electronic structure of catalyst poses a great influence on the electrocatalytic HER and OER activity since electronic structure plays a crucial role in modulating the catalyst/electrolyte interaction. [87][88][89][90] Typically, heteroatom doping has been widely accepted as a promising strategy for modulating the electronic structure of catalyst. [91,92] In recent years, Ru-based nanocatalysts with modified electronic structures have been widely investigated and designed for boosting electrocatalytic reactions.…”

Synthesis, properties and catalytic performance of the novel, pseudo-spinel, multicomponent transition-metal selenides

“…Another group of TMCh exhibiting similar structural features to pentlandites, yet much less studied, are densepacked, Se-based, monoclinic C2/m-structured pseudo-spinels, characterized by the presence of only octahedral cationic sites. Similarly, as in pentlandites, the very close, intermetallic interactions between cations, together with a clear tendency for creation of Ch vacancies, have the potential for providing a high concentration of active sites, 31,[35][36][37] making them highly promising bifunctional catalysts. For instance, extremely high current densities of 400 mA cm −2 at an overpotential of 320 mV dec −1 (OER) were reported for monometallic Co 3 Se 4 anchored to cobalt foam.…”

Recent Progress in Transition-Metal Sulfide Catalyst Regulation for Improved Oxygen Evolution Reaction

“…High sulfur defects can be controllably prepared by increasing the doped amount of Mo n + doping; therefore, the Mo–Ni 3 S 2 QD electrocatalyst was determined to have high catalytic performance for OER. Similarly, the sulfur vacancy of cobalt sulfide can be regulated by a self-generated H 2 S atmosphere with different amounts of thiourea . A hollow dodecahedron with vacancy-rich spinel Co 3 S 4 nanoparticles was fabricated by an anion exchange process and vacancy introduction simultaneously benefiting from the self-generated H 2 S (Figure a).…”

“…(d) Schematic illustration showing the conversion of Co­(III) to Co­(II) in the process of introducing sulfur vacancies. [Adapted with permission from ref . Copyright 2022.…”

“…Similarly, the sulfur vacancy of cobalt sulfide can be regulated by a self-generated H 2 S atmosphere with different amounts of thiourea. 136 A hollow dodecahedron with vacancy-rich spinel Co 3 S 4 nanoparticles was fabricated by an anion exchange process and vacancy introduction simultaneously benefiting from the self-generated H 2 S (Figure 4a). A low overpotential of 270 mV to reach 10 mA cm −2 and a small Tafel slope of 59 mV dec −1 were observed for this catalyst (see Figures 4b and 4c); the neighboring electron delocalization of cobalt and more Co 2+ site exposure in spinel Co 3 S 4 induced by the vacancy engineering could promote the formation of Co 3+ active sites for OER (Figure 4d).…”