Effect of synergy on selective low-temperature dehydrogenation of propane to propylene over a defect-induced copper titanium catalyst†

The TiO₂-supported Cu catalyst exhibits high activity in the dehydrogenation of propane at low temperatures, enabling the selective production of propylene over a prolonged period. The defect-induced Cu–TiO₂ catalyst provided a propylene yield of 10.4% with high selectivity (∼91.9%) even at 375 °C. Surface analysis shows that the defects on the TiO₂ surface are extrinsic and arise from doping with Cu entities. This enhanced metal–support synergy between Cu and TiO₂ passivates C–C bond breaking, which indirectly reduces methane formation. To understand the effect of different Cu planes on the adsorption of propane molecules for their activation and conversion, the DFT-optimized geometry and reaction coordinates were investigated. The DFT study revealed that the Cu–TiO₂ surface enhances C–H activation at lower temperatures while maintaining an encouraging propylene yield. Furthermore, the kinetic study suggests that adsorption is the rate-limiting step besides the surface reaction, and the activation energy for the propane dehydrogenation reaction is 50.04 kJ mol⁻¹.