<p>The development of high-performance and durable nanocatalysts for the degradation of toxic pollutants remains highly desirable. Herein, we report a facile, room-temperature, and surfactant-free strategy for the synthesis of highly efficient and stable nanocatalysts through the self-assembly of N-doped carbon dots (CDs), derived from pomelo peel and urea as carbon and nitrogen precursors, respectively, onto Ag nanoparticles. With NaBH₄ serving as a reducing agent, the resulting Ag nanoparticles exhibited a quasi-spherical morphology with particle sizes ranging from 5 to 50&#xa0;nm and a face-centered cubic crystal structure. Notably, the N-doped CDs/Ag nanocomposites demonstrated markedly enhanced catalytic activity toward the reduction of 4-nitrophenol (4-NP) compared with the undoped CDs/Ag nanocomposites. Kinetic analysis revealed pseudo-first-order behavior, with the N-doped CDs/Ag nanocomposites exhibiting significantly higher apparent rate constants (k_app of 0.99 vs. 0.31&#xa0;min^− 1) and specific activity factors (k_norm of 495000 vs. 155000&#xa0;min^− 1 g^− 1). The catalytic efficacy increased with increasing the NaBH₄/4-NP molar ratio and catalyst loading, eventually reaching saturation. Furthermore, the N-doped CDs/Ag hybrids demonstrated good stability and reusability, maintaining complete conversion and stable reaction time during six cycles. These results highlight the beneficial role of N-doped CDs as supporting materials in enhancing catalytic performance.</p> Graphical Abstract <p></p>