Electrocatalytic hydrogen evolution reaction (HER) is regarded as a sustainable and green way for H2 generation, which faces a great challenge in designing highly active, stable electrocatalysts to replace the state-of-art noble metal-platinum catalysts. 1T MoS2 is highly promising in this regard, but the synthesis and stability of this is a particularly pressing task. Here, a phase engineering strategy has been proposed to achieve a stable, high-percentage (88%) 1T MoS2 /chlorophyll-a hetero-nanostructure, through a photo-induced donation of anti-bonding electrons from chlorophyll-a (CHL-a) highest occupied molecular orbital to 2H MoS2 lowest unoccupied molecular orbital. The resultant catalyst has abundant binding sites provided by the coordination of magnesium atom in the CHL-a macro-cycle, featuring higher binding strength and low Gibbs-free energy. This metal-free heterostructure exhibits excellent stability via band renormalization of Mo 4d orbital which creates the pseudogap-like structure by lifting the degeneracy of projected density of state with 4S in 1T MoS2 . It shows extremely low overpotential, toward the acidic HER (68 mV at the current density of 10 mA cm-2 ), very close to the Pt/C catalyst (53 mV). The high electrochemical-surface-area and electrochemical turnover frequency support enhanced active sites along with near zero Gibbs free energy. Such a surface-reconstruction strategy provides a new avenue toward the production of efficient non-noble-metal-catalysts for the HER with the aim of green-hydrogen production.
Keywords: chlorophyll-a; density functional theory; hydrogen evolution reaction; molybdenum disulfide; phase transition; van der Waal heterostructures.
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