Ammonia‐source, used to attain the desired pH during synthesis, is conceived to influence the physical characteristics of ZnO‐based nanomaterials, and the catalytic activity is susceptible to surface characteristics of semiconductor–photocatalyst. In this context, Ni0.5Zn0.5Fe2O4‐dispersed In2O3‐spotted ZnO nanoparticles have been obtained by using either tetramethyl ammonium hydroxide or ammonium carbonate as ammonia‐source at identical pH (9) using identical quantities of the precursors following identical synthetic procedure. The nanoparticles have been characterized using energy dispersive X‐ray spectroscopy, elemental mapping, selected area electron and X‐ray diffractometries, transmission electron microscopy, etc. The nanoparticles obtained using ammonium carbonate possess larger (1) pore width, (2) pore volume, and (3) surface area compared with nanoparticles prepared employing tetramethyl ammonium hydroxide. Although the electrical properties of both the samples do not differ remarkably, the violet light‐absorption of the sample prepared using the carbonate is slightly larger than that of the other sample. Further, the In2O3‐spotting is slightly larger on using ammonium carbonate than using tetramethyl ammonium hydroxide. To degrade dye under visible light, the sample obtained using ammonium carbonate shows larger catalytic activity compared with nanoparticles prepared using tetramethyl ammonium hydroxide. The observed photocatalytic activities are explained based on the surface characteristics.