Leveraging synergistic interfaces in NiO and NiO/rGO heterostructures for enhanced microwave absorption

• Published in: Surfaces and interfaces 2025-01, Vol.56, p.105617, Article 105617
• Main Authors: Rekha Phani, P․S․D․, Sahu, Somnath, Gurrala, Ravi Chandra, Dobbidi, Pamu, Raidongia, Kalyan, Latha, B․Swarna, Babu, B․Kishore, Annapurna, N․
• Format: Article
• Language: English
• Subjects: Electromagnetic parameters; Microflower; Microwave absorption; Reflection loss
• ISSN: 2468-0230
• DOI: 10.1016/j.surfin.2024.105617

Materials engineered for electromagnetic wave absorption are essential in military, aerospace, and electronics applications. Optimizing morphology has proven effective in enhancing microwave attenuation by utilizing interfacial polarization. In this study, hierarchical 3D flower-like NiO and NiO/rGO composites are studied via a hydrothermal method, and their structural, microstructural, and electromagnetic properties are comprehensively examined. The XPS spectra indicated increased oxygen vacancies in the NiO/rGO composite, contributing to enhanced microwave absorption. Integrating rGO into NiO generated oxygen vacancies, offsetting charge imbalances and promoting interfacial and dipolar polarization. The conductive rGO network and the flower-like NiO morphology enhanced dielectric loss, as the unique structure provided a large surface area and effective impedance mismatch. Additionally, the folded and curled nanosheets extended the propagation paths of electromagnetic waves, enabling multiple reflections and greater attenuation. The NiO and NiO/rGO composites achieved maximum reflection losses of -40 dB and -60 dB, respectively, at a 2 mm thickness. These findings underscore the potential of 3D flower-like NiO and NiO/rGO composites for high-performance microwave absorption. [Display omitted]