Holey 2D Metal Nitride Nanosheets as Efficient Hybridization Matrices to Maximize the Mass Activity of Metal Nanoclusters

A novel effective hybridization strategy to optimize the gravimetric electrocatalytic functionality of metal nanoclusters is developed by the synergetic tailoring of the surface polarity and crystal defect of conductive holey substrate. As an emerging conductive hybridization matrix, holey titanium oxynitride 2D nanosheet with nitrogen vacancies is synthesized by the ammonolysis of exfoliated titanate nanosheet due to the aliovalent substitution of divalent O²^- ion with trivalent N³^- ion. The nitrogen vacancies in holey titanium oxynitride nanosheet can act as efficient anchoring sites for Pt nanoclusters. The resulting strongly-coupled Pt-TiN₁_-xO_x nanohybrids commonly display excellent electrocatalyst performances for hydrogen evolution reaction (HER) with unusually high efficiency per Pt mass. The excellent electrocatalyst performance of Pt-holey-TiO₁_-xN_x nanohybrid can be ascribed to the increased porosity, improved charge/mass transport and enhanced electrocatalytic kinetics, as well as the downshift of the <i>d</i>-band center upon intimate coupling with holey-TiO₁_-xN_x. The present study underscores that employing holey titanium oxynitride nanosheet as an immobilization matrix provides useful way of exploring high-performance electrocatalysts via enhanced interfacial chemical interaction.