Moro Ouma Cecil Naphtaly, Modisha Phillimon, Bessarabov Dmitri
HySA Infrastructure Centre of Competence, Faculty of Engineering, North-West University (NWU) P. Bag X6001 Potchefstroom 2520 South Africa
RSC Adv. 2018 Sep 12;8(56):31895-31904. doi: 10.1039/c8ra05800h.
Liquid organic hydrogen carriers (LOHCs) are considered to be safe and efficient hydrogen storage media with high hydrogen storage capacities. Adsorption of the LOHC perhydro--dibenzyltoluene ( = (), (), ()) isomers on (100), (110) and (111) planar surfaces of Pd, Pt and a 50 : 50 PtPd alloy were investigated, using density functional theory with van der Waals corrections. The calculated heats of formation of the isomers indicated that all the isomers considered were energetically stable. Surface selectivity to isomer adsorption was investigated, using isomer adsorption preference and energies. The (110) surface was found to be highly preferred by the different isomers, compared with both the (100) and the (111) surfaces. Among the isomers, isomer-surface attachment occurred most often in the case of perhydro--dibenzyltoluene and perhydro--dibenzyltoluene adsorption. The LOHC isomer adsorption on different surfaces was found to be spontaneous, energetically stable and exothermic, with high isomer adsorption preference for Pt and PtPd surfaces, compared with Pd surfaces. This indicates the ease of loading of the LOHC on Pt and PtPd surfaces, for subsequent dehydrogenation.
液态有机氢载体（LOHCs）被认为是具有高储氢容量的安全高效储氢介质。利用含范德华修正的密度泛函理论，研究了全氢化二苄基甲苯（ = （），（），（））异构体在钯（Pd）、铂（Pt）以及50 : 50铂钯（PtPd）合金的（100）、（110）和（111）平面表面上的吸附情况。计算得到的异构体生成热表明，所有考虑的异构体在能量上都是稳定的。利用异构体吸附偏好和能量研究了异构体吸附的表面选择性。结果发现，与（100）和（111）表面相比，（110）表面受到不同异构体的高度青睐。在这些异构体中，全氢化二苄基甲苯和全氢化二苄基甲苯吸附时，异构体与表面的附着最为常见。研究发现，LOHC异构体在不同表面上的吸附是自发的、能量稳定的且放热的，与Pd表面相比，对Pt和PtPd表面具有较高的异构体吸附偏好。这表明LOHC易于负载在Pt和PtPd表面上，以便后续脱氢。
