Engineered WO3 nanorods for conformal growth of WO3/BiVO4 core-shell heterojunction towards efficient photoelectrochemical water oxidation

High aspect ratio WO3 nanorods were obtained by post growth transformation of ammonium tungsten bronze ((NH4)(0.33)center dot WO3) nanorods which are grown via a facile solvothermal method. Influence of capping agents, reaction temperature and annealing temperature on the morphologies and performances of (NH4)(0.33)center dot WO3 films have been investigated and the growth mechanism of (NH4)(0.33)center dot WO3 nanorods was also explored. The results show that NH4 (+) plays a key role for formation of rod-like morphology at appropriate reaction temperature. Monoclinic WO3 nanorods were obtained via removal of ammonium by annealing the synthesized (NH4)(0.33)center dot WO3 at 500 A degrees C in air. Conformal WO3/BiVO4 heterojunction was also synthesized using PLD to extend its light harvest range as well as enhance the charge separation. The heterojunction was characterized to demonstrate efficient photocatalytic water splitting by core-shell arrays constructed based on high aspect ratio nanowires.