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Dibenzyltoluene (DBT) is a promising liquid organic hydrogen carrier (LOHC) with theoretical 6.2 wt % hydrogen storage capacity which can be coupled with a renewable energy power generation system. In this work, the surface hydroxyl groups and surface oxygen vacancies (SOVs) on alumina were modified by a convenient and environmentally friendly plasma treatment method. Different Pt/Al 2 O 3 catalysts were prepared via impregnation of the treated alumina, and the effects of different surface hydroxyl groups and SOVs on their reactivity for the reversible hydrogenation and dehydrogenation of DBT were investigated. The results show that SOVs increased after H 2 plasma treatment, whereas the surface hydroxyl groups increased and SOVs decreased after O 2 plasma treatment. Both the surface hydroxyl group and SOV can improve Pt metal dispersion. The more interesting observation is that the hydroxyl groups promote hydrogen spillover and the proportion of Pt(0), which not only benefit the catalyst hydrogenation and dehydrogenation activity but also reduce side reactions and increase long-term cycle performance. However, increased SOVs increased the fraction of low coordinated Pt which reduces the long-term cycle performance of the catalyst. As a result, increasing surface hydroxyl groups and appropriately reducing SOVs on Pt/Al 2 O 3 are propitious for improving both reactivity and long-term cycle performance when using DBT as a LOHC.

High quality electron beams with flat distributions in both energy and current are critical for many accelerator-based scientific facilities such as free-electron lasers and MeV ultrafast electron diffraction and microscopes. In this Letter, we report on using corrugated structures to compensate for the beam nonlinear energy chirp imprinted by the curvature of the radio-frequency field, leading to a significant reduction in beam energy spread. By using a pair of corrugated structures with orthogonal orientations, we show that the quadrupole wakefields, which, otherwise, increase beam emittance, can be effectively canceled. This work also extends the applications of corrugated structures to the low beam charge (a few pC) and low beam energy (a few MeV) regime and may have a strong impact in many accelerator-based facilities.

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