. 2026 Aug 12;16(39):43391–43413. doi: 10.1039/d6ra01860b

Table 4. Overview of hydrogenation process using common LOHC candidates concerning catalyst types, reactor configurations, kinetics and performance.

LOHC system	Typical catalyst (s)	Reactor configuration	Operating conditions	Kinetic characteristics	Advantages	Limitations	Ref.
Toluene to methylcyclohexane (MCH)	Noble metals (Pt, Pd, Ru) on oxide supports	Fixed-bed/trickle-bed (gas-liquid-solid)	185–225 °C; 0.3–2 MPa	Fast hydrogenation kinetics; activation energy ≈ 35–50 kJ mol⁻¹, depending on the catalyst; equilibrium-limited at high conversion	Mature chemistry; good logistics compatibility; fast hydrogenation kinetics	Catalyst cost: heat removal needed (exothermic); overall system limited by dehydrogenation step	75–78
Dibenzyltoluene (DBT) to Perhydro-DBT (H18-DBT)	Mainly Ru-based and Pt/Pd catalysts (supported)	Fixed bed; continuous flow systems	120–250 °C; 30–50 bar	Activation energy ≈ 45–60 kJ mol⁻¹; reaction often limited by heat and mass transfer due to high viscosity	DBT is low-volatility and stable, attractive for large-scale storage logistics	Viscosity/mass transfer constraints; concerns with catalyst deactivation; hydrogenation heat management	46 and 79
Dibenzyltoluene (DBT) to Perhydro-DBT (H18-DBT)	Mainly Ru-based and Pt/Pd catalysts (supported)	Fixed bed; continuous flow systems	120–250 °C; 30–50 bar	Enthalphy: −65.4 kJ mol_H₂⁻¹			46 and 79
N-ethylcarbazole (NEC) to 12H-NEC	Mainly Ru, also Pt/Pd, depending on design	Fixed-bed and batch screening reactors	Temperature: 130–180 °C and pressure 50–80 bar	Activation energy ≈ 30 to 70 kJ mol⁻¹	High hydrogen capacity class; potentially lower energy requirement for dehydrogenation vs. hydrocarbons	Carrier/catalyst sensitivity; possible by-product formation; careful purity control needed	80 and 81
N-ethylcarbazole (NEC) to 12H-NEC	Mainly Ru, also Pt/Pd, depending on design	Fixed-bed and batch screening reactors	Temperature: 130–180 °C and pressure 50–80 bar	Enthaplhy: −50 kJ mol_H₂⁻¹			80 and 81
Hydrogenation of LOHCs	Noble metals are dominant; Ni-based materials are explored as a lower-cost alternative	Trickle-bed/slurry/fixed-bed	Conditions tuned by carrier and catalyst		Strong industrial knowledge base from refinery hydrogenation; scalable reactor choices	Non-noble catalysts may show lower activity or stability; long-term cycling is critical	11, 82 and 83
Hydrogenation process design	Catalyst choice depends on heat removal, selectivity, and stability	Heat-integrated fixed-bed and process loops	Exothermic heat must be controlled		Hydrogenation heat can be recovered for system efficiency	Hotspots can accelerate deactivation; scale-up requires thermal control and gas–liquid mass transfer optimisation	84–88