SnO_x@β–SnO heterostructures and their enhanced photocurrent in photoelectrochemical cell

To improve the effective separation of the photogenerated electrons and holes, SnO_x@β–SnO composites on titanium meshes were prepared by using a standard one-step hydrothermal procedure. As photoanodes in photoelectrochemical cell, the SnO_x@β–SnO composites exhibited a photocurrent density of 150 μA cm⁻² at 0.0 V versus Ag/AgCl under visible light illumination. The improved photocurrent can be explained as, the Sn²⁺ 5s impurity states in SnO₂ have a band gap energy of 2.24 eV, SnO_x@β–SnO composites construct a type-II heterojunction. And titanium meshes have a good conductivity, which is beneficial to transferring electron from the conduction band of SnO₂ to external circuit. Furthermore, the SnO_x@β–SnO heterostructures have a larger electrochemical specific surface area, and stronger light absorption from 350–800 nm. (paper)