Critical role of CoO modification on Pt/Al₂O₃ for efficient H18-DBT dehydrogenation in LOHC systems

Abstract

Liquid organic hydrogen carriers (LOHCs) represent a highly promising strategy for hydrogen storage and long-distance transport, offering a safe and economically viable solution to key infrastructure challenges. The effective application of LOHCs requires dehydrogenation catalysts that strike an optimal balance between activity and stability. Herein, we report a precisely engineered CoO_x-modified Pt/Al₂O₃ catalytic system that exhibits outstanding performance in the dehydrogenation of perhydro-dibenzyltoluene (H18-DBT). Systematic investigations identify a critical CoO_x loading threshold at 1 wt%, at which the catalyst achieves a maximum dehydrogenation degree (DoD) of 93% and a H₂ production rate of 20.98 × 10³ {\mathrm{m}\mathrm{o}\mathrm{l}}_{{\mathrm{H}}_2}∙mol_Pt^–1∙h^–1 at 300 °C for dehydrogenation, outperforming all the catalysts reported in the literature. However, increasing the Co loading from 1 to 10 wt% results in a sharp decline in DoD from 93% to 7.2%. With the increasing CoO_x content, the cobalt species initially form amorphous CoO clusters, which subsequently transform into crystalline Co₃O₄. The amorphous CoO is found to be the key species responsible for enhanced dehydrogenation activity by increasing the electron density and reducing the particle size of Pt, thereby promoting dehydrogenation while suppressing the hydrogenation capability.

Graphical abstract

Keywords

LOHCs / DBT / CoO / Pt based-bimetallic catalyst / H₂ storage

References

[1] Sarmah M K , Singh T P , Kalita P , Dewan A . Sustainable hydrogen generation and storage—a review. RSC Advances, 2023, 13(36): 25253–25275

[2] Agyekum E B , Tarawneh B , Rashid F L . State-of-the-art review of liquid organic hydrogen carriers for hydrogen storage and transport: challenges and perspectives. Applied Energy, 2025, 400: 126555

[3] Tan R , Ji Q , Ling Y , Li L . Advances in liquid organic hydrogen carriers: developing efficient dehydrogenation strategies. Chemical Communications, 2024, 60(63): 8186–8203

[4] Mekonnin A S , Wacławiak K , Humayun M , Zhang S , Ullah H . Hydrogen storage technology, and its challenges: a review. Catalysts, 2025, 15(3): 260

[5] Sattar M A , Rasul M G , Jahirul M I , Hasan M M . An up-to-date review on the progress and challenges of hydrogen storage, and its safety and economic analysis. Sustainable Energy & Fuels, 2024, 8(16): 3545–3573

[6] Tang J , Xie R , Pishva P , Shen X , Zhu Y , Peng Z . Recent progress and perspectives of liquid organic hydrogen carrier electrochemistry for energy applications. Journal of Materials Chemistry A: Materials for Energy and Sustainability, 2024, 12(26): 15580–15591

[7] He Z , Li K , Chen T , Feng Y , Villalobos-Portillo E , Marini C , Lo T W B , Yang F , Zhang L , Liu L . High-purity hydrogen production from dehydrogenation of methylcyclohexane catalyzed by zeolite-encapsulated subnanometer platinum-iron clusters. Nature Communications, 2025, 16(1): 92

[8] Wu H , Zhang J , Wang Z , Kong X , Li G , Zhao Y , Yang P , Liu Z . Recent advances in non-noble metal catalysts toward N-ethylcarbazole hydrogen storage. Journal of Materials Chemistry A: Materials for Energy and Sustainability, 2024, 13(1): 20–35

[9] Zhao Y , Zhu T , Li J , Li C , Lu W , Liu J , Zhang D , Dong Y , Yang M . Electron-deficient Co^δ+ induced by synergistic Co-ZnO-ZnAl₂O₄ interface interactions for enhanced N-propylcarbazole hydrogenation. ACS Catalysis, 2025, 15(7): 5490–5502

[10] Dong Y , Yang M , Yang Z , Ke H , Cheng H . Catalytic hydrogenation and dehydrogenation of N-ethylindole as a new heteroaromatic liquid organic hydrogen carrier. International Journal of Hydrogen Energy, 2015, 40(34): 10918–10922

[11] Li L , Yang M , Dong Y , Mei P , Cheng H . Hydrogen storage and release from a new promising liquid organic hydrogen storage carrier (LOHC): 2-methylindole. International Journal of Hydrogen Energy, 2016, 41(36): 16129–16134

[12] Chen Z , Yang M , Zhu T , Zhang Z , Chen X , Liu Z , Dong Y , Cheng G , Cheng H . 7-ethylindole: a new efficient liquid organic hydrogen carrier with fast kinetics. International Journal of Hydrogen Energy, 2018, 43(28): 12688–12696

[13] Yang M , Cheng G , Xie D , Zhu T , Dong Y , Ke H , Cheng H . Study of hydrogenation and dehydrogenation of 1-methylindole for reversible onboard hydrogen storage application. International Journal of Hydrogen Energy, 2018, 43(18): 8868–8876

[14] Yang M , Xing X , Zhu T , Chen X , Dong Y , Cheng H . Fast hydrogenation kinetics of acridine as a candidate of liquid organic hydrogen carrier family with high capacity. Journal of Energy Chemistry, 2020, 41: 115–119

[15] Shi L , Qi S , Qu J , Che T , Yi C , Yang B . Integration of hydrogenation and dehydrogenation based on dibenzyltoluene as liquid organic hydrogen energy carrier. International Journal of Hydrogen Energy, 2019, 44(11): 5345–5354

[16] Brückner N , Obesser K , Bösmann A , Teichmann D , Arlt W , Dungs J , Wasserscheid P . Evaluation of industrially applied heat-transfer fluids as liquid organic hydrogen carrier systems. ChemSusChem, 2014, 7(1): 229–235

[17] Leinweber A , Müller K . Hydrogenation of the liquid organic hydrogen carrier compound monobenzyl toluene: reaction pathway and kinetic effects. Energy Technology, 2018, 6(3): 513–520

[18] Markiewicz M , Zhang Y Q , Bösmann A , Brückner N , Thöming J , Wasserscheid P , Stolte S . Environmental and health impact assessment of liquid organic hydrogen carrier (LOHC) systems—challenges and preliminary results. Energy & Environmental Science, 2015, 8(3): 1035–1045

[19] Modisha P M , Jordaan J H L , Bösmann A , Wasserscheid P , Bessarabov D . Analysis of reaction mixtures of perhydro-dibenzyltoluene using two-dimensional gas chromatography and single quadrupole gas chromatography. International Journal of Hydrogen Energy, 2018, 43(11): 5620–5636

[20] Salman M S , Rambhujun N , Pratthana C , Srivastava K , Aguey-Zinsou K F . Catalysis in liquid organic hydrogen storage: recent advances, challenges, and perspectives. Industrial & Engineering Chemistry Research, 2022, 61(18): 6067–6105

[21] Sisáková K , Podrojková N , Oriňaková R , Oriňak A . Novel catalysts for dibenzyltoluene as a potential liquid organic hydrogen carrier use—a mini-review. Energy & Fuels, 2021, 35(9): 7608–7623

[22] Shi L , Zhou Y , Qi S , Smith K J , Tan X , Yan J , Yi C . Pt catalysts supported on H₂ and O₂ plasma-treated Al₂O₃ for hydrogenation and dehydrogenation of the liquid organic hydrogen carrier pair dibenzyltoluene and perhydrodibenzyltoluene. ACS Catalysis, 2020, 10(18): 10661–10671

[23] Ali A , Rohini A K , Noh Y S , Moon D J , Lee H J . Hydrogenation of dibenzyltoluene and the catalytic performance of Pt/Al₂O₃ with various Pt loadings for hydrogen production from perhydro-dibenzyltoluene. International Journal of Energy Research, 2022, 46(5): 6672–6688

[24] Kwak Y , Kirk J , Moon S , Ohm T , Lee Y J , Jang M , Park L H , Ahn C I , Jeong H , Sohn H . et al. Hydrogen production from homocyclic liquid organic hydrogen carriers (LOHCs): benchmarking studies and energy-economic analyses. Energy Conversion and Management, 2021, 239: 114124

[25] Geißelbrecht M , Benker R , Seidel A , Preuster P . Modeling of the continuous dehydrogenation of perhydro-dibenzyltoluene in a cuboid reactor. Energy Technology, 2024, 12(4): 2300813

[26] Auer F , Blaumeiser D , Bauer T , Bösmann A , Szesni N , Libuda J , Wasserscheid P . Boosting the activity of hydrogen release from liquid organic hydrogen carrier systems by sulfur-additives to Pt on alumina catalysts. Catalysis Science & Technology, 2019, 9(13): 3537–3547

[27] Shi L , Zhou Y , Tan X , Qi S , Smith K J , Yi C , Yang B . The effects of alumina morphology and Pt electron property on reversible hydrogenation and dehydrogenation of dibenzyltoluene as a liquid organic hydrogen carrier. International Journal of Hydrogen Energy, 2022, 47(7): 4704–4715

[28] Kim C H , Lee M W , Jang J S , Lee S H , Lee K Y . Enhanced activity of a WO_x-incorporated Pt/Al₂O₃ catalyst for the dehydrogenation of homocyclic LOHCs: effects of impregnation sequence on Pt-WO_x interactions. Fuel, 2022, 313: 122654

[29] Park T I , Lee S H , Lee K Y . Characteristics of La-doped Pt/Al₂O₃ catalyst prepared by solvent-deficient method and effect on enhancement of dehydrogenation of perhydrodibenzyltoluene. Korean Journal of Chemical Engineering, 2023, 40(1): 97–103

[30] Lei N , Qiu S , Zhang L , Zhao G , Wang S , Liu K . Synergistic effect between Pt and CrO_x on reversible hydrogenation and dehydrogenation of dibenzyltoluene. Industrial & Engineering Chemistry Research, 2025, 64(9): 4761–4770

[31] Xiao M , Wu Q , Ku R , Zhou L , Long C , Liang J , Mavrič A , Li L , Zhu J , Valant M . et al. Self-adaptive amorphous CoO_xCl_y electrocatalyst for sustainable chlorine evolution in acidic brine. Nature Communications, 2023, 14(1): 5356

[32] Yuan H . Laser Raman spectra study on Co-Mo/Al₂O₃ hydrodesulphurization catalysts. Spectroscopy and Spectral Analysis, 2014, 34(2): 435–438

[33] López A , Navascues N , Mallada R , Irusta S . Pt-CoO_x nanoparticles supported on ETS-10 for preferential oxidation of CO reaction. Applied Catalysis A General, 2016, 528: 86–92

[34] Modisha P , Garidzirai R , Güneş H , Bozbag S E , Rommel S , Uzunlar E , Aindow M , Erkey C , Bessarabov D . A promising catalyst for the dehydrogenation of perhydro-dibenzyltoluene: Pt/Al₂O₃ prepared by supercritical CO₂ deposition. Catalysts, 2022, 12(5): 489

[35] Fu N , Wang R , Gu X , Wang Y , Ren J , Zheng Z . Size-modulated Pt nanoparticles for low-temperature plasmon-enhanced hydrogen production from aqueous phase reforming of methanol. Chemical Engineering Journal, 2024, 498: 155825

[36] Ding K , Gulec A , Johnson A M , Schweitzer N M , Stucky G D , Marks L D , Stair P C . Identification of active sites in CO oxidation and water-gas shift over supported Pt catalysts. Science, 2015, 350(6257): 189–192

[37] DeRita L , Dai S , Lopez-Zepeda K , Pham N , Graham G W , Pan X , Christopher P . Catalyst architecture for stable single atom dispersion enables site-specific spectroscopic and reactivity measurements of CO adsorbed to Pt atoms, oxidized Pt clusters, and metallic Pt clusters on TiO₂. Journal of the American Chemical Society, 2017, 139(40): 14150–14165

[38] Kale M J , Christopher P . Utilizing quantitative in situ FTIR spectroscopy to identify well-coordinated Pt atoms as the active site for CO oxidation on Al₂O₃-supported Pt catalysts. ACS Catalysis, 2016, 6(8): 5599–5609

[39] Liu A , Liu X , Liu L , Pu Y , Guo K , Tan W , Gao S , Luo Y , Yu S , Si R . et al. Getting insights into the temperature-specific active sites on platinum nanoparticles for CO oxidation: a combined in situ spectroscopic and ab initio density functional theory study. ACS Catalysis, 2019, 9(9): 7759–7768

[40] Guan Q , Zhu C , Lin Y , Vovk E I , Zhou X , Yang Y , Yu H , Cao L , Wang H , Zhang X . et al. Bimetallic monolayer catalyst breaks the activity–selectivity trade-off on metal particle size for efficient chemoselective hydrogenations. Nature Catalysis, 2021, 4(10): 840–849

[41] Cao C , Guan W , Liu Q , Li L , Su Y , Liu F , Wang A , Zhang T . Selective hydrogenolysis of furfural to 1, 2-pentanediol over a Pt-Fe/MT catalyst under mild conditions. Green Chemistry, 2024, 26(11): 6511–6519

[42] Gao Y , Thakur N , Uchiyama T , Cao W , Yamamoto K , Watanabe T , Kumar M , Sato R , Teranishi T , Imai H . et al. Investigating degradation mechanisms in PtCo alloy catalysts: the role of Co content and a Pt-rich shell using operando high-energy resolution fluorescence detection X-ray absorption spectroscopy. ACS Applied Materials & Interfaces, 2023, 15(45): 52473–52484

[43] Farkaš B , Perry C B , Jones G , de Leeuw N H . Adsorbate-induced segregation of cobalt from PtCo nanoparticles: modeling Au doping and core AuCo alloying for the improvement of fuel cell cathode catalysts. Journal of Physical Chemistry C: Nanomaterials and Interfaces, 2020, 124(33): 18321–18334

[44] Shi L , Qi S , Smith K J , Alamoudi M , Zhou Y . Dehydrogenation of the liquid organic hydrogen carrier perhydrodibenzyltoluene—reaction pathway over Pt/Al₂O₃. Reaction Chemistry & Engineering, 2022, 8(1): 96–103

[45] Zhou Y , Shi L , Qi S , Tan X , Yi C , Yang B . Exploring the dehydrogenation reaction pathway of perhydro-polycyclic aromatic hydrocarbons over the Pt/Al₂O₃ catalyst as liquid organic hydrogen carriers by in situ DRIFT. Journal of Physical Chemistry A, 2023, 127(5): 1179–1189

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