Effect of the Seed Layer on the Growth and Charge Transfer Behavior of Zn2SnO4 Nanorods in Photoelectrochemical Water Splitting

Abstract

The growth of Zn₂SnO₄ nanorods on two differently prepared ZnO seed layers is demonstrated using a hydrothermal approach. The ZnO seed layers are prepared using dip-coating and electrodeposition techniques. The grown Zn₂SnO₄ nanorods are in the cubic phase. However, the different seed layers result in alternation in the diameter of grown Zn₂SnO₄ nanorods. The photocurrent of Zn₂SnO₄ nanorods grown on an electrodeposited ZnO seed layer is ∼4.5 times larger than that of Zn₂SnO₄ grown on a dip-coated ZnO seed layer. The Nyquist plots of Zn₂SnO₄ nanorods on the electrodeposited ZnO seed layer result in a lower charge transfer resistance (R_ct = 37.7 Ω) and a lower bulk resistance (R_bulk = 64 kΩ), improving the charge transport properties. The change in diameter of Zn₂SnO₄ nanorods significantly alters the charge transfer behavior. The calculated charge injection efficiency did not exhibit a significant change. However, there was a 1.6-fold enhancement observed in the charge separation efficiency for Zn₂SnO₄ when grown on an electrodeposited seed layer.