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Topochemical Transformation of Two-Dimensional VSe 2 into Metallic Nonlayered VO 2 for Water Splitting Reactions in Acidic and Alkaline Media

2021; American Chemical Society; Volume: 16; Issue: 1 Linguagem: Inglês

10.1021/acsnano.1c06662

1936-086X

Leyla Najafi, Reinier Oropesa‐Nuñez, Sebastiano Bellani, Beatriz Martín‐García, Lea Pasquale, Michele Serri, Filippo Drago, Jan Luxa, Zdeněk Sofer, David Sedmidubský, Rosaria Brescia, Simone Lauciello, Marilena Isabella Zappia, Dipak V. Shinde, Liberato Manna, Francesco Bonaccorso,

Electrocatalysts for Energy Conversion

The engineering of the structural and morphological properties of nanomaterials is a fundamental aspect to attain desired performance in energy storage/conversion systems and multifunctional composites. We report the synthesis of room temperature-stable metallic rutile VO2 (VO2 (R)) nanosheets by topochemically transforming liquid-phase exfoliated VSe2 in a reductive Ar-H2 atmosphere. The as-produced VO2 (R) represents an example of two-dimensional (2D) nonlayered materials, whose bulk counterparts do not have a layered structure composed by layers held together by van der Waals force or electrostatic forces between charged layers and counterbalancing ions amid them. By pretreating the VSe2 nanosheets by O2 plasma, the resulting 2D VO2 (R) nanosheets exhibit a porous morphology that increases the material specific surface area while introducing defective sites. The as-synthesized porous (holey)-VO2 (R) nanosheets are investigated as metallic catalysts for the water splitting reactions in both acidic and alkaline media, reaching a maximum mass activity of 972.3 A g-1 at -0.300 V vs RHE for the hydrogen evolution reaction (HER) in 0.5 M H2SO4 (faradaic efficiency = 100%, overpotential for the HER at 10 mA cm-2 = 0.184 V) and a mass activity (calculated for a non 100% faradaic efficiency) of 745.9 A g-1 at +1.580 V vs RHE for the oxygen evolution reaction (OER) in 1 M KOH (overpotential for the OER at 10 mA cm-2 = 0.209 V). By demonstrating proof-of-concept electrolyzers, our results show the possibility to synthesize special material phases through topochemical conversion of 2D materials for advanced energy-related applications.