Engineering a Layered-Differentiation Core-Shell Architecture: NiCoAlOx@Pt-ZSM-5 for Synergistically Enhanced Activity and Dual H2O/SO2 Resistance in Propane Oxidation

Abstract

Pt-based catalysts, though efficient for alkane C-H activation, suffer from water and SO2 poisoning due to competitive adsorption on Pt sites. Herein, a core-shell Ni1Co0.5AlOx@Pt/ZSM-5 catalyst was constructed to improve its anti-poisoning performance through supramolecular assembly, featuring a layered differentiation function. The ZSM-5 shell selectively sequesters H2O and SO2, preventing their access to Pt sites, while promoting the formation of active species such as Pt0, Co3+, and adsorbed oxygen. The optimized catalyst exhibits enhanced activity, water resistance, and sulfur tolerance in propane combustion. In-situ DRIFTS confirmed the oxidation reaction pathway as follows: propane is first activated at Pt0 sites to form isopropyl species, subsequently oxidized via Co3+-mediated sites into intermediates such as propene and acetate salts, and finally fully converted into CO2 and H2O with the participation of adsorbed oxygen. DFT calculations elucidated that this catalyst achieves superior propane oxidation activity and dual H2O/SO2 resistance via strengthened propane adsorption, reduced reaction energy barriers, and selective trapping of H2O/SO2 by the ZSM-5 shell. This atomic-level insight verifies that H2O and SO2 are preferentially sequestered by the ZSM-5 shell (rather than occupying Pt active sites), thus ensuring efficient propane/O2 diffusion to Pt surfaces. This work provides a rational design strategy for robust, poisoning-resistant VOCs oxidation catalysts.