The mixed solution was stirred at around 100°C for 15 min to form the well-distributed polyacrylate salt, and then dried at 250°C for 2 h to remove the solvent. Finally, yellow NiTiO3 nanoparticles were obtained after calcination of the solids in air at 600 and 800 ºC for 2 h, respectively, and denoted as NiTiO3-600 ºC and NiTiO3-800 ºC,
respectively.