Abstract: | A comparative study on the role of urea in controlling the morphology of calcium‐bismuth (Ca5Bi3) bimetallic nanoparticles is carried out. Calcium‐bismuth bimetallic nanoparticles are synthesized in the presence and absence of urea using the solvothermal method. The morphology of the synthesized products is analyzed by scanning electron microscopy. The composition of the product is analyzed by energy‐dispersive X‐ray spectroscopic and X‐ray diffraction (XRD) analyses. Reitveld refinements are performed on the XRD data, and lattice parameters are optimized. Reitveld‐refined parameters are used to construct the structural model of the calcium‐bismuth product. The formation mechanism of needle like particles from an orthorhombic unit cell is also proposed. The degradation of Congo red dye is catalyzed by synthesized Ca5Bi3 bimetallic nanoneedles in an aqueous medium. The effect of catalyst dose on the apparent rate constant (kapp) of degradation is studied and compared with literature. Ca5Bi3 bimetallic nanoneedles are also used as an additive in commercial diesel obtained from Pakistan State Oil, Limited. The effect of an additive dose on the calorific value of diesel is studied. How the Ca5Bi3 additive influenced other fuel quality parameters such as flash point, fire point, pour point, cloud point, kinematic viscosity, and specific gravity is also studied. |