2D Pt Metals at Rectifying Interface with Pronounced Negative Charge Density for Electrocatalytic Reduction Reactions

Abstract

Noble metals often exhibit excellent catalytic activity when downsized into two-dimensional (2D) metals owing to their high atomic utilization and unique electronic properties. However, the controllable formation of 2D metals/support composites with clean interfaces/surfaces for practical applications still remains a synthetic bottleneck, with rather limited cases of 2D metals prepared through metal–support bonds. Herein, we developed a built-in electronic interface-guided method for in situ reduction of preadsorbed Pt atoms into 2D Pt metals along the surface of 2D nitrogen-doped carbon (NC) support through the electronic interaction at nonbonded metal–support interface. The interfacial electron exchange, driven by the difference in work functions between 2D Pt metals and NC support, enables the controllable synthesis of 2D Pt-based Schottky heterojunctions with clean interfaces/surfaces and a mean Pt thickness of 1.3 nm. Both experimental and theoretical results confirm the enhanced electron exchange at the interface between 2D Pt and the 2D NC support, resulting in a doubled electron density for 2D Pt. Consequently, the electron-rich 2D Pt metals exhibit remarkable mass activity of 67.3 A mg_Pt^–1 for the hydrogen evolution reaction (HER) and a turnover frequency (TOF) value of 117 h^–1 in the electrocatalytic hydrogenation of phenol, notably outperforming those of the commercial Pt/C catalyst by a factor of 16.8 and 4.0, respectively. Our efficient built-in electronic interface-guided method not only facilitates the synthesis of novel 2D metal/2D support Schottky heterojunctions but also lays the groundwork for designing more powerful electronic interface catalysts with enhanced and diversified functionalities.