Two‐Step Thermal Upcycling of Flexible Printed Circuit Board Waste Into Metallic Copper Nanoparticles: Synthesis and Characterization

ABSTRACT The rapid increase in electronic waste, especially from flexible printed circuit boards (FPCB), presents a growing environmental challenge, demanding urgent and sustainable resource recovery solutions. This study presents a robust two‐step thermal upcycling process, leveraging low‐temperature polymer degradation (700°C) followed by high‐temperature arc discharge (2600°C), to extract and transform copper from waste FPCBs into high‐purity copper nanoparticles (CuNPs). The synthesized CuNPs exhibit a predominantly spherical morphology under 100 nm, with an agglomerated structure featuring interstitial voids and a surface area of 7.31 m 2 g −1 . Elemental and phase analyses verified a purity of 96% copper with detectable cuprous oxide (Cu 2 O), with high‐resolution TEM indicating a lattice spacing of 0.203 nm assigned to the Cu(111) plane. The nitrogen adsorption‐desorption behavior at high relative pressure was successfully determined to reflect interparticle voids created by nanoparticle agglomeration rather than intrinsic mesoporosity. This process exemplifies a circular economy model by converting hazardous e‐waste into functional nanomaterials without a wet‐chemical synthesis step. Ultimately, our findings highlight how advanced resource recovery strategies can address critical electronic waste recycling challenges and contribute to sustainable metal recovery.