Bifunctional Au@MoS2 nanoflowers for solar-enhanced sulfur ion oxidation coupled nitrite reduction electrochemical purification system

Addressing the dual challenge of water pollution and high energy costs in treatment processes, this study reports an integrated electrochemical system engineered for simultaneous pollutant removal and resource recovery. We designed a bifunctional electrocatalyst, plasmonic Au nanoparticles loaded on MoS 2 nanoflowers (Au@MoS 2 NFs), and implemented it in a novel reactor configuration that couples nitrite reduction (NO 2 RR) with sulfur ion oxidation (SOR). This process design is the key to overcoming the primary economic barrier of traditional electrolysis: by replacing the energy-intensive oxygen evolution reaction (OER) with thermodynamically favorable SOR, we achieve an operational voltage reduction of 1.48 V. Further process optimization was achieved by integrating solar energy, where plasmonic enhancement boosted ammonia yield to 4.9 mg h −1 mg cat −1 (~100 % FE), a 25 % increase that lowers the overall energy input. This work demonstrates an economically attractive engineering solution, transforming a waste stream into valuable ammonia and sulfur with significant energy savings and robust stability under practical, intermittent conditions.