Efficient cyclohexane dehydrogenation over Pt/B-ZrO₂ for H₂ production

The efficient storage and release of H₂ are pivotal for the advancement of hydrogen energy technologies. Cyclohexane, as a promising liquid organic hydrogen carrier (LOHC), provides a safe and practical solution for H₂ storage. However, the performance limitations of dehydrogenation catalysts have hindered the rapid development of LOHC technology. In this study, we successfully developed boron-modified Pt/ZrO₂ catalysts, which exhibit exceptional catalytic performance in cyclohexane dehydrogenation. The optimal boron content is determined to be 0.5 wt.%, with the Pt/0.5B-ZrO₂ catalyst achieving high turnover frequency (TOF) of 10,627.3 mol_H2·mol_Pt^-1·h^-1 and benzene selectivity of 99% at 295 °C. The catalyst also demonstrates H₂ evolution rate of 908 mmol·g_Pt^-1·min^-1 and low deactivation rate of 0.0043 h^-1. Remarkably, the catalyst displays outstanding stability and regeneration performance, maintaining its activity without significant loss during a 60-hour dehydrogenation reaction and retaining a cyclohexane conversion of 77.2% after 10 consecutive cycles. Comprehensive characterization techniques, including XPS, CO-FTIR, NH₃-TPD, H₂-TPD, Benzene-TPD, and Py-IR, reveals that boron modification reduces the electron density of Pt, generating abundant electron-deficient Pt atoms. These electron-deficient Pt atoms enhances H₂ adsorption and accelerated benzene desorption, effectively preventing coke formation from deep benzene dehydrogenation, which is responsible for the high catalytic performance of the Pt/0.5B-ZrO₂ catalyst. These findings offer a valuable strategy for optimizing dehydrogenation catalysts in liquid organic hydrogen carrier (LOHC) technologies, addressing a critical bottleneck in the development of this essential energy storage solution.