Carbon Dot Composite Mixed Ionic-Electronic Device Based on Oxygen-Proton Coupling Catalytic Mechanism.

Here, we report a memristive device based on a carbon dot-polyaniline (CDot-PANI) composite, working with an oxygen/proton coupled catalytic mechanism. Under external proton and oxygen stimulation, CDots catalyze a proton-assisted oxygen reduction reaction (ORR), which accelerates electron/proton transfer and dynamically modulates the ES/PNB redox transition of PANI. This coupled ORR-oxidation pathway enables fully reversible, catalyst-driven switching between high- and low-conductance states. The CDot-PANI composite exhibits strengthened electronic transport, high structural stability, and pronounced hysteretic switching behavior. Importantly, the coupled oxygen/proton stimuli trigger a spectrum of synaptic functions, including tunable short- and long-term plasticity (STP-LTP) and brain-like learning-forgetting dynamics, demonstrating that neuromorphic behaviors originate from electrochemically mediated catalytic processes rather than conventional filamentary or vacancy-based mechanisms. A fully coupled Poisson-Nernst-Planck (PNP) and Butler-Volmer (B-V) kinetic model further reveals the formation of ORR-induced proton concentration gradients, nonuniform potential distributions, and deep ion penetration arising from cascade oxygen-proton redox reactions. These simulations suggest that the memristive switching stems from catalytic reaction-driven ionic redistribution within the composite. This work establishes a mechanistic basis for metal-free mixed ionic-electronic devices and a design strategy for neuromorphic electronics.