Ga2O3, GaN and AIN nanowires and nanoscale tetrapod-like ZnO can be easily synthesized by heating appropriate metals Ga, Al and Zn with SiO2 powder and a fine catalyst of Fe2O3 supported by alumina in argon or ammonia atmosphere. The reaction of the metals with SiO2 and Fe2O3 produces Si and Fe. The alloyed Fe and Si can effectively reduce the melting point of the catalyst and a liquid catalyst drop can be formed, which initiates vapor-liquid-solid growth of the nanowires. Silica is also the oxygen source in synthesizing the oxide nanowires.