Vacancy-fused multiple layers of copper sulfoselenide superstructures: a propitious HER electrocatalyst in acidic medium. Issue 3 (4th January 2023)

• Record Type: Journal Article
• Authors: Kumaravel, Sangeetha; Kumar, Dhirendra; Sam Sankar, Selvasundarasekar; Karmakar, Arun; Madhu, Ragunath; Bera, Krishnendu; Dhandapani, Hariharan N.; Nagappan, Sreenivasan; Chakraborty, Sudip; Kundu, Subrata
• Is Part Of: Catalysis science & technology. Volume 13:Issue 3(2023)
• Page Start: 694
• Page End: 704
• Publication Date: 2023-01-04
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/d2cy01336c
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : A wet-chemically prepared 'CuS–Se@Cu foam' has been studied for acidic HER ( η 100 = 309 mV). The presence of oxygen vacancies and multiple layers induced maximum intercalation of electrolytes and supported a low Δ G H* value of −0.36 eV for HER. Abstract : An advanced vacancy-rich bi-chalcogenide, Cu2 S–Se@Cu, was perceived to be a highly efficient and sustainable catalyst towards HER in acid due to its synergistic effects. Interestingly, the selenization of Cu2 S@Cu foams created oxygen vacancies with enriched layered Cu2 S–Se superstructures by wet-chemical and hydrothermal approaches. The best catalyst Cu2 S–Se@Cu-Wet exhibited a small overpotential of 315 mV at 100 mA cm −2 and a low Tafel slope of 97 mV dec −1 . Benefiting from the intrinsic activity, Cu2 S–Se-Wet delivered a high mass activity of 2675 mA mg −1 cm −2 and a turnover frequency of 0.371 s −1 . Moreover, the Faradaic efficiency measured by gas chromatography (GC) for Cu2 S–Se@Cu-Wet showed 97.16% efficiency. Density functional theory (DFT) studies for HERs depicted that Cu2 S–Se at the surface of the Cu(001) plane revealed a favourable free energy Δ G H* of −0.36 eV. From the density of states (DoS), it is affirmed that Cu2 S–Se over the Cu surface has reduced the band gap close to zero, which stressed the enhanced HER catalytic activity with O-vacancies. The HER enhancement of such vacancy with the electrocatalytic system creates a new response toward stability and reproducibility in the near future.