Molecular Trapping Strategy To Stabilize Subnanometric Pt Clusters for Highly Active Electrocatalysis

Structure engineering is an effective way to substantially adjust the chemical and physical properties of materials. However, the effects of structure engineering of carbon hosts on the catalytic properties of Pt-based catalysts at the molecular scale are poorly understood. Herein, we report a molecular-level strategy to anchor and stabilize subnanometric Pt clusters on a covalently coupled host of graphitic carbon nitride (g-C3N4) and carbon nanotubes (CNT) for the development of electrocatalysts with high activities toward methanol oxidation reactions. Theoretical evaluation and experimental validation identified that the chemical integration of g-C3N4 on CNT is critical in optimizing the electronic structures and catalytic properties of Pt catalysts. As a result, the Pt-g-C3N4-CNT possesses a high energy level of d-band position, significantly strengthening its adsorption behaviors for the key reaction intermediates during the methanol electrooxidation process and energetically decreasing the energy barriers in the multistep reaction pathways. Combining with the strong catalyst–support interactions afforded by the adaptive coordination environment of g-C3N4 with Pt clusters as well as the unimpeded electron transfer via a σ-orbital overlap between CNTs and g-C3N4, the as-obtained Pt-g-C3N4-CNT possesses prodigious electrocatalytic properties including high activities, unusual poison tolerance, and reliable long-term discharge stabilities toward methanol oxidation reactions, in comparison to commercial Pt/activated carbon (Pt-AC) and Pt-CNT catalysts. This molecular-level finding opens up a new avenue to design and develop more efficient and effective carbon-based supports for fabricating advanced heterogeneous catalysts and could also be extended to more applications, such as lithium-ion batteries, lithium-sulfur batteries, supercapacitors, and sensors.