From physisorption to chemisorption: Modulation of thermal conductance at metal/graphene/metal interfaces and the role of hydrogenation

Interfacial thermal conductance (ITC) in metal/graphene/metal contacts depends on interfacial bonding and can be tuned by surface functionalization. Building on prior evidence that single-sided hydrogenation strengthens coupling in Cu/graphene/Cu, we extend the study to Ni/graphene/Ni and heterogeneous Ni/graphene/Cu contacts. The expanded dataset reveals a material-dependent response to hydrogenation. Chemisorption enhances thermal transport through strong bonding and shorter separation, whereas physisorption yields weak coupling and low conductance. Single-sided hydrogenation induces charge transfer, converts physisorption to chemisorption, and raises ITC in Cu/graphene/Cu. However, Ni/graphene/Ni hydrogenation enlarges the separation, weakens interfacial hybridization, and lowers ITC. In Cu–Ni stacks, the outcome depends on which side is hydrogenated. These findings provide mechanistic insights into adsorption-type-dependent heat transport and suggest strategies for tuning graphene–metal interfaces for thermal management applications.