Nitrogen-skinned carbon nanocone enables non-dynamic electrochemistry of individual metal particles

Nano-impact electrochemistry is an efficient way to probe the physical and chemical properties of individual particles. Unfortunately, limited by the weak adsorption between particles and a microelectrode (ME), the particle collision events evolve randomly to be elastic or inelastic. These events occur intermittently to produce unmarked transient signal sets that seriously interfere with single particle measurement. Here, we report a nitrogen-skinned carbon nanocone electrode (NS-CNCE) to enhance its adsorption capacity greatly towards metal particles and thus realize non-dynamic (i.e., inelastic impacts) single particle analysis. The surface of NS-CNCEs characteristic of excellent adhesion, smoothness, and conductivity can effectively capture the landing metal particles to form a stable contact for efficient electronic communication. Using superior NS-CNCEs, we investigated electrochemical oxidation of Ag (or Au) particles and electrocatalytic amplification of Pt particles, respectively, under non-dynamic electrochemistry. The determined particle size is highly consistent with the physical characterization. Statistical analysis of transient signals confirms the strong adhesion of NS-CNCEs to metal particles, which is also in line with the prediction of a particle-electrode adsorption energy model. The proposed strategy has effectively solved the major challenge of general single metal particle collision analysis.