Synthesis of uniform octahedral tungsten trioxide by RF induction thermal plasma and its application in gas sensing

Well-defined uniform octahedral WO3 are prepared via a simple one-step thermal plasma technique. The detailed structures of the synthesized materials are characterized by XRD, EDX, FESEM, SAED and HRTEM. Each octahedron is nearly perfect with a highly symmetric, regular shape containing 8 facets, 6 vertices, and 12 edges, which exhibit sharp edges and corners as well as smooth surfaces. Processing parameters dependent experiments are performed to control its shape and size distribution. The regular octahedral WO3 shows good sensing properties to benzene gas, which might mainly be due to its highly exposed {111} faces and the regular octahedral shape.