Preparation and electrocatalytic property of three-dimensional nano-dendritic platinum oxide film

Platinum oxide electrode, as an important part of hydrogen concentration monitoring sensor built in containment, needs to withstand extreme conditions such as high temperature, high humidity, and high irradiation and can still work normally even in the case of serious accidents, which puts forward higher requirements for its performance. In present study, platinum oxide film electrode was successfully prepared with three-dimensional nano-dendritic, uniform, and crack-free on platinum substrate by reactive magnetron sputtering, and the influence of different substrate temperature and sputtering atmosphere on the composition, morphology, and electrocatalytic property of the film was investigated. The results show that platinum oxide film is composed of PtO and PtO₂. As the temperature increases from room temperature (RT) to 200°C, the oxygen vacancies in the amorphous film are gradually repaired and convert to the crystalline state, which shows increasing PtO₂ ratio, increasing electrochemical active area (ECSA), and improved stability. When the temperature is rising to 400°C, the film shows decreasing oxygen vacancies, increasing average grain size. Because PtO₂ decomposes into PtO and Pt, and thus ECSA decreases, the stability and oxygen reduction activity of the films decreases gradually. At the same temperature, the crystalline film obtained in Ar/50%O₂ has higher concentration of oxygen vacancies and smaller average grain size than that obtained in O₂, resulting in larger ECSA and relatively good stability. By contrast, the platinum oxide film electrode prepared in Ar/50%O₂ and 200°C has better stability and excellent electrocatalytic activity for oxygen reduction.