Precursor-Engineered Strategy for Constructing Supported Tetra-Atom Pt Clusters to Boost Propane Dehydrogenation under Direct Resistive Heating.

Abstract

The commercial platinum-based catalysts used in propane dehydrogenation (PDH) reactions face challenges such as ambiguous active sites, low stability, and poor propylene selectivity. Atomically precise platinum catalysts, featuring well-defined active structures and controllable electronic properties, offer an effective approach to addressing these issues. Herein, we successfully constructed atomically precise Pt₄ nanoclusters stabilized on oxygen-functionalized carbon nanotubes (Pt₄/OCNT) through a precursor-engineered strategy. Combined advanced characterization and density functional theory (DFT) calculations revealed that the Pt₄ clusters are consistent with the tetrahedral model stabilized by Pt-C/O bonds with the support. Under direct resistive heating for PDH at 500 °C, Pt₄/OCNT reached 99.6% propylene selectivity while exhibiting the highest space-time conversion, demonstrating superior performance compared to both atomically dispersed Pt₁/OCNT and industrial Pt/C catalysts. In situ infrared characterization combined with DFT calculations further demonstrated that Pt₄/OCNT effectively stabilizes key dehydrogenation intermediates and transition states through multisite cooperative interactions, thereby lowering the activation barrier for PDH. Furthermore, the weak adsorption of propylene on Pt₄/OCNT suppresses side reactions and enhances selectivity. This work presents a precursor-engineered strategy for constructing atomically precise supported Pt₄/OCNT with exact nuclearity. Direct resistive heating is further employed during the PDH reaction as an auxiliary means to promote catalytic performance. The atomically precise synthesis enables control over the nuclearity and structure of the supported clusters and provides a general strategy for the design of atomically precise supported cluster catalysts (APSCCs).