Internal and external cultivation design of spinel-type CuMn2O4 toward boosted high infrared emissivity

Spinel CuMn₂O₄ (CMO) attracts enormous attentions as a cost-efficiency high infrared radiative material toward energy-saving scenarios. However, its modest infrared emissivity is always a huge challenge and bottleneck for practical application. For this, an internal and external cultivation strategy is purposefully proposed to design and fabricate cobalt-doped CMO (CCMO) wrinkled microspheres (MSs) with superb high infrared emissivity via a spray drying avenue. Benefiting from the smart “internal (i.e., appropriate Co³⁺ doping dominated local lattice distortion, oxygen vacancy and band gap narrowing) and external (i.e., porous wrinkled micro-spheric architecture) cultivation” design, the optimum CCMO-25 (i.e., molar ratio of Co to Mn is 2.5 to 7.5) is endowed with the highest infrared emissivity of 0.96 at 500 °C within the wavelength range of 3 – 5 μm. Moreover, owing to synergistic contributions from both porous sphere-like merits of CCMO-25 and the fluffy and porous characteristics of coating itself, the CCMO-25 based infrared radiative coating exhibits outstanding interfacial bonding, thermal shock resistance, and infrared radiation properties on both metal and ceramics substrates. More essentially, our insights here will provide a meaningful guidance for rationally constructing advanced high infrared radiative materials toward energy consumption in a green and sustainable way.