A new study published in Engineering provides new insights into regulating the catalytic dehydrogenation performance of liquid organic hydrogen carriers (LOHCs) by precisely modulating the d electron structure of platinum (Pt) catalysts. Researchers from Tianjin University and its affiliated institutions prepared a series of Pt/MOₓ catalysts with uniform Pt nanoparticle size around 1.7 nm, supported on CeO₂, MgO, ZrO₂, TiO₂, Al₂O₃, or SiO₂, to explore the relationship between electronic metal–support interactions and catalytic behavior.

LOHCs, including perhydro-monobenzyltoluene/monobenzyltoluene (H12-MBT/H0-MBT) and perhydro-dibenzyltoluene/dibenzyltoluene (H18-DBT/H0-DBT), are regarded as promising materials for large-scale hydrogen storage and transportation, but their dehydrogenation process is limited by low efficiency and high energy consumption. Platinum-based catalysts are widely used for LOHC dehydrogenation due to their strong C–H bond activation ability, yet the influence of Pt electron structure regulated by different supports has not been systematically studied under controlled particle size conditions.

In this work, the research team eliminated the interference of geometric effects by strictly controlling Pt nanoparticle size at approximately 1.7 nm and support particle size within 20–50 nm, focusing on the electronic effects of metal–support interactions. Characterization results from in situ X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge structure (XANES) spectroscopy, and in situ CO adsorption diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) confirmed that different oxide supports induce continuous changes in the d electron density of Pt nanoparticles. The d electron density of Pt decreases in the order of SiO₂ > α-Al₂O₃ ≈ γ-Al₂O₃ > TiO₂ > ZrO₂ > MgO > CeO₂, showing a positive correlation with the binding energy shift of Pt 4f and 4d orbitals and the white-line intensity at the Pt L_Ⅲ edge.

Catalytic evaluation results show a volcano-shaped correlation between Pt d electron density and dehydrogenation turnover frequency (TOF) for both H12-MBT and H18-DBT substrates. Among all prepared catalysts, Pt/MgO exhibits the highest dehydrogenation activity, while Pt/SiO₂ shows the lowest activity. Long-term stability tests indicate that Pt/MgO maintains stable performance without obvious deactivation, and the coke deposition amount is lower than that of other catalysts under the same reaction conditions.

Density functional theory (DFT) calculations further reveal the mechanism: appropriately reduced d electron density on Pt/MgO enhances the bonding orbital dominance of Pt–C bonds, stabilizing the adsorption of H6-MBT intermediates and lowering the activation energy barrier for the initial C–H bond cleavage. Excessively low d electron density on Pt/CeO₂ weakens Pt–C bonding strength, leading to unstable intermediate adsorption and increased energy barriers for C–H activation.

This study clarifies the regulatory mechanism of Pt d electrons on LOHC dehydrogenation catalysis and offers a rational design strategy for high-efficiency dehydrogenation catalysts by electronic structure modulation, which is expected to support the development and practical application of advanced hydrogen storage and release technologies based on liquid organic hydrogen carriers.

The paper “Rational Modulation of Pt d Electrons to Significantly Enhance the Catalytic Dehydrogenation Performance of Liquid Organic Hydrogen Carriers,” is authored by Chao Sun, Tianzuo Wang, Ruijie Gao, Xiaoyang Liu, Kang Xue, Chengxiang Shi, Xiangwen Zhang, Lun Pan, Ji-Jun Zou. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.07.045. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.