## 1 Introduction  
In several important applications such as electronics, optics, magnetism, catalysis to energy storage and conversion, spinel type materials have long attracted scientific and technological consideration [1]. Versatile applications for manganese-based spinels (MMn\({}_{2}\)O\({}_{4}\)) were determined in the case of lithium insertion electrodes, magnetic solids and catalysts [2; 3; 4]. For medical applications, including bio imaging, target drug development and hyperthermia, certain materials were being used [5; 6]. The different benefits of manganese, such as low cost, easy implementation, low toxicity, multiple valence and a prominent Jahn-Teller effect, could be related to these behaviors [7].  
Among the numerous varieties of manganese-based spinels, one of the most incredibly interesting composite oxides is hopcalite (CuMn\({}_{2}\)O\({}_{4}\) or Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\)) since it is very appropriate to several catalytic processes such as water-gas transfer, the reduction of nitrogen oxide with carbon monoxide, the direct decomposition of NO, selective ammonia oxidation to nitrogen gas and, more recently, in steam reforming and oxidative steam reforming of methanol, and the selective oxidation of carbon monoxide, benzyl alcohol and toluene [8; 9; 10; 11]. Towards the production of copper-manganese mixed oxides, different preparation techniques have been employed. Co-precipitation, deposition-precipitation, impregnation, sol-gel, solvothermal and combustion methods include such techniques [12; 13; 14; 15]. It is reported that due to Jahn-Teller distortion, the crystal structure of manganese-based spinels, such as spinel lithium manganese oxide (LiMn\({}_{2}\)O\({}_{4}\)), often has a tetragonal unit cell, but under certain preparation conditions it can become cubic [16].  
The processing of single phase containing hopcalite nanoparticles is complicated, depending upon if the secondary phase of manganese and copper is more likely to be implemented during the synthesis process. In our previous work, the solid state reaction between both copper nitrate and manganese carbonate resulted in the production of a Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\) spinel compound with the subsequent formation of both Mn\({}_{2}\)O\({}_{3}\) and CuO. In the same way, the use of copper chloride as a CuO source brought about the formation of both CuMn\({}_{2}\)O\({}_{4}\) and Mn\({}_{2}\)O\({}_{3}\)[15]. Researchers have focused on the synthesis of such a compound by the fusion of copper with manganese metals or by the coprecipitation technique of certain modifications to avoid such a challenge [15; 16; 17; 18]. The high concentration of Cu\({}^{+}\) and Mn\({}^{4+}\) cations in Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\) solid could activate O\({}_{2}\) and NO\({}_{x}\) in the diesel exhaust and convert these gases to NO\({}_{2}\), so this solid is expected to be quite favorable for diesel soot combustion [18]. Consequently, a few disadvantages, such as the complication of preparation methods, remain. The rapid and reasonable synthesis of crystalline spinels at room temperature and ambient atmosphere, however, represents a problem, despite continuous efforts.  
In this research, to prepare copper maganite nanoparticles (Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\) NPs) through egg white assisted green synthesis, a facial, scalable and environmentally friendly method was used. Here, we demonstrate the experimental method of preparing Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\) nanoparticles through using egg white as an auxiliary bio material, which provides the dispersion of nanoscale oxides in one phase. The single-step process is straightforward, environmentally friendly, inexpensive and reproducible, generating high-quality nanoparticles of Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\) that can be regulated in terms of structure, morphology and distribution of particle size. The characterization of the Cu\({}_{1.5}\)Mn\({}_{1.5}\)O\({}_{4}\) NPs and magnetic properties developed has been determined.