Boosting Propane Dehydrogenation on ZnO/Al2O3 via Ni Single Atom-Modified Hydrogen Transfer Kinetics

Abstract The intrinsic activity-stability trade-off remains a fundamental constraint for metal oxide catalysts in propane dehydrogenation (PDH). Herein, we break this limitation via a well-defined dual-site catalyst comprising ZnO clusters and adjacent Ni single atoms on γ-Al2O3, constructed through a metal-doped carbon dot precursor strategy. This configuration achieves a 5-fold and 2-fold enhancement in propylene formation rate compared to the sole Ni and ZnO catalysts, respectively, while maintaining high propylene selectivity (>93%) and long-term stability over 100 h. Combined kinetic and in situ spectroscopic studies establish a cooperative mechanism wherein under-coordinated Zn2+ sites serve as the primary centers for C−H activation, while neighboring (Ni−)O sites function as dynamic regulators of interfacial hydrogen transfer. Direct evidence from temperature-programmed D2 adsorption and time-resolved propane DRIFTS reveals that the hydrogen transfer rate scales linearly with Ni loading, correlating inversely with the apparent activation energy for dehydrogenation. This (Ni−)O-mediated process dynamically reduces surface hydrogen coverage on ZnO, lowers the energy barrier for C−H cleavage, and concurrently suppresses C−C cracking pathways. This work establishes a design paradigm of using atomically dispersed metals as kinetic regulators of surface hydrogen dynamics, shifting the promoter role from static modifier to active mediator of surface pathways, offering a general strategy for advanced metal oxide catalyst design in alkane dehydrogenation.