Revealing the spin-polarization-induced d-band splitting effect of Fe-series atoms on the dehydrogenation performance of Pt/TiO2 catalyst for Dodecahydro-N-ethylcarbazole

Abstract

Liquid organic hydrogen carriers (LOHC) technology has emerged as one of the most promising novel hydrogen storage approaches, whose bottleneck is the need to develop efficient and low-cost dehydrogenation catalysts. Among various catalytic systems, Pt-based bimetallic catalysts have attracted significant research attention due to their superior catalytic performance and potential for cost reduction. In this study, we conducted a systematic investigation into the influence of the introduction of Fe-series atoms (Fe, Co, Ni) on 12H-NECZ dehydrogenation reactions of Pt/TiO₂ catalyst. The results demonstrate that the introduced Fe-series atoms facilitate enhanced orbital hybridization, particularly between their 3d orbitals and the Pt-5d orbitals, leading to a pronounced spin polarization effect, modulating the d-band splitting (Δε_d). These atoms have excellent electron migration properties, which increase the electron density around the Pt atoms. This electronic restructuring modulates the dual d-band centers of the metal Pt, weakens the strong adsorption of reaction intermediates/products and dramatically reduces the energy barrier of the breaking of C–H bonds. Specifically, the rate-determining-step (RDS) barrier of the most effective Pt₃Co/TiO₂ catalyst is 0.43 eV lower than that of Pt/TiO₂, which is attributed to the moderate spin polarization strength and optimal electron structure, balancing the adsorption of intermediates/products (ε_d↑) and hydrogen (ε_d↓). This study establishes a theoretical foundation for the design of cost-effective, high-performance dehydrogenation catalysts for LOHC.