Proton Transfers at the Water/Solid Interface of α-Al₂O₃–Supported Ni Clusters under Steam Reforming Conditions: An AIMD Study

Water in contact with a solid surface under ambient conditions is known to have a profound impact on reaction processes. However, many industrial heterogeneous catalytic reactions are operated under very harsh conditions that often involve extreme temperature and pressure in which the complexity of the dynamic water/solid interface is greatly concealed. Herein, we use ab initio molecular dynamics to uncover the fast transfer of protons at the three-phase interface of water steam and an Al2O3-supported Ni cluster under extremely high temperature conditions for methane steam reforming, one of the most important industrial processes for hydrogen production. Through experimental and computational studies, we have shown that the facile dissociation of water at the support near the interfacial region is the driving force of proton transfer occurring at the steam/Ni/α-Al2O3 interface. The proton transfer leads to the hydroxylation of the Ni cluster and thereby greatly facilitates the activation of the stable CH4 molecule. This finding is essential for understanding proton transfer at high temperatures in water-oxide–supported interfaces with metal catalytic systems at the atomic level.