Physicochemical characterisation of electrosynthesized lead dioxide coatings on Ti/SnO2-Sb substrates

SnO2, as an undercoat, has been recently applied on Ti substrate to prepare PbO2 anodes to improve the stability and electro-catalytic activity. In this work, we explored the electro-deposition of PbO2 on the Ti substrate with a Sb-doped SnO2 undercoat, from a traditional acidic nitrate solution. The morphology and microstructure of the PbO2 coatings were investigated by varying electro-deposition temperature and time. It is found that the Sb-doped SnO2 undercoat significantly promotes the electro-deposition process of PbO2. At a low electro-deposition temperature, a preferential crystallographic orientation is usually observed in the coatings, which exhibit a caterpillar-like morphology. At a higher deposition temperature, the PbO2 coatings display a more tightly packed pyramid-like morphology. The crystallite size increases with deposition temperature. Electrochemical performance of the deposited PbO2 largely depends on their morphologies and microstructures. It is suggested that deep reaction path, high porosity and good connectivity between crystallites play a synergic role in determining the electrochemical performance of the PbO2 coatings.