Fused Filament Fabrication (FFF) enables rapid and low-cost manufacturing of metal-based 3D-printed components with customizable geometries. However, as-printed metallic systems typically suffer from poor electrical conductivity, necessitating tedious activation post-treatments, such as high-temperature annealing or electroplating technologies, to make them suitable for electrochemical applications. While effective, these methods are costly, time-consuming, and environmentally unfriendly, also requiring specialized equipment. Herein, we report a green wet-chemical activation strategy based on sodium borohydride (NaBH 4 ), as a mild reducing agent, which induces room-temperature chemical sintering in 3D-printed copper electrodes (3D-CuEs). As a proof-of-concept, the NaBH 4 -activated 3D-CuEs have been successfully applied to the voltammetric determination of nitrate (NO 3 – ) in water via nitrate reduction reaction (NRR), exhibiting a wide linear range (1.5–2553 ppm), a low detection limit of 1.5 ppm, and excellent recoveries in real water samples. Overall, this sustainable and scalable activation method provides a versatile route toward the large-scale fabrication of high-performance metal-based 3D-printed electrodes, opening new opportunities for advanced electrochemical applications. • Environmentally friendly wet-chemical activation of 3D-CuEs using NaBH4. • NaBH4 provides electrically active 3D-CuEs via chemical sintering. • NaBH4-activated 3D-CuEs enable sensitive nitrate detection via NRR. • Excellent recoveries in real samples demonstrate practical applicability.
Li et al. (Wed,) studied this question.