Influence of Ni and S co-doping of SnO2 on Its Electrochemical Performance

SnO2 has received considerable interest in the electrochemical field due to its low cost, good stability and easy fabrication. However, the drawback of low electrocatalytic efficiency remains great challenge to overcome. Thus, the (Ni, S) co-doped SnO2, Ni doped SnO2, S doped SnO2 and pure SnO2 nanoparticles were prepared by hydrothermal method to address this problem. The surface morphology, crystal configuration and valence state of element of the samples were characterised. The cyclic voltammetry curve, linear sweep voltammetry and electrochemical impedance curve were determined using a three-electrode system. Meanwhile, the electronic structure of the samples was investigated by first principle calculation. Compared with SnO2, the sample has a more uniform surface, and has no impurity phase after doping. The doped Ni and S atoms respectively replace the Sn and O atoms in the SnO2 crystal, decreasing the band gap to 0.014 eV. The oxygen evolution potential of (Ni, S)-SnO2 reaches the maximum of 1.74 V, the current density reaches maximum and the charge transfer resistance is the lowest, indicating that the electrochemical performance of (Ni, S)-SnO2 is the best. This study offers an important guide for modification by co-doping to improve the electrochemical performance of SnO2.