Revealing the modification mechanism of La-doped Ti/SnO2 electrodes related to the microelectronic structure by first-principles calculations

Highlights: • The electrocatalytic behaviors of La doped SnO₂ electrode were investigated. • The optimum La doping ratio1.39 mol% was determined. • First principles calculations were performed to study the La doped SnO₂ lattice. • The modification mechanism was revealed from the microscopic view. Elemental doping can improve the performance of an electrode, and revealing the modification mechanism is highly significant to prepare high-performance electrode materials. To investigate the modification mechanism of La doping on the electronic structure of SnO₂, first-principles calculations using plane-wave pseudopotential technology based on density functional theory (DFT) were performed. First, the geometric structures of La-doped SnO₂ crystals were optimized. Second, the property changes of La-doped SnO₂, including the lattice constants, energy band structure, density of states and formation energy, were studied. Finally, the theoretical calculation results were verified by proper experimental studies of the electrode catalytic activity. By increasing the La doping concentration, the band gap first decreased and then increased, and the density of states at the Fermi level first increased and then decreased. The calculation results showed that the optimum La concentration was 1.39%. La doping enhanced the acceptor density, increased the quantity of holes in the valence band and improved the carrier concentration. Meanwhile, the structure of SnO₂ was the most stable with a La doping concentration of 1.39%. These results revealed the relationship between the lattice change caused by La doping and the catalytic activity of the electrode based on the microstructure and improved the theoretical understanding of the preparation of high-performance electrode materials.