Tailoring the Hydrothermal Synthesis of Stainless Steel Wire Sieve-Supported Ag-Doped ZnO Nanowires to Optimize Their Photo-catalytic Activity

Batches of un-doped and Ag-doped ZnO nanowires (ZnONWs) were prepared hydrothermally on stainless steel wire sieves at varied Zn 2+ concentrations of the growth solution and at different Ag + concentrations of the silver nitrate solution. Methylene blue solution was degraded with these as-prepared ZnONWs in the presences of ultraviolet irradiation. It is found that both the processing parameters greatly affect the surface textures, wettability, and photo-activity of the ZnONWs. The latter synthesizing parameter is optimized only after the former one has been finely regulated. The un-doped and Ag-doped ZnONWs at Zn 2+ concentration of 75 mM of the growth solution and at Ag + concentration of3 mM of the silver nitrate solution both produce Gaussian rough surfaces and in each batch are most hydrophilic. Therefore, in the related batch the contacting surface area of the catalyst is the largest, the hydroxyl radicals attached on the top ends of corresponding ZnONWs the most, and the catalytic activity of these catalysts the optimal. Besides these, the latter synthesizing parameter affects the photo-activity of Ag-doped ZnONWs more significantly than the former one does that of un-doped ZnONWs.