Tip-Intensified Interfacial Microenvironment Reconstruction Promotes an Electrocatalytic Chlorine Evolution Reaction

Electrocatalysis applied in energy conversions has recently been associated with nanotips that catalyze extensive fuel-forming or value-adding reactions. However, the enhanced catalytic behavior governed by tip-intensified microenvironment reconstruction is particularly elusive and is yet to be understood. Here, we demonstrated a homemade visualization platform to collect information from the local microenvironment of a solution near an electrode (LMSE) with high temporal–spatial resolution, thereby figuring out the sharp-tip enhancement effect for the chlorine evolution reaction (CER). Through visualization using sensitive Cl– and pH sensors, we confirmed that periodic nanoneedles were beneficial for field-induced anion concentration, giving priority to water dissociation and synchronously creating optimal pH conditions for triggering the CER, whereby the Cl– consumption rate within the LMSE was 1.3 times higher than that of the slab counterpart. Tip-enhanced effects meanwhile endowed the local microenvironment with intensified concentration and temperature gradients for continuous transport of Cl– substrates and effective diffusion of HClO products, whereby the oxygen evolution reaction for persistent CER activities was restrained. Our study provides definitive evidence that the optimal microenvironment functionalized with tip-intensified ion concentration from the electrolyte and water dissociation at tip sites are key to stabilize the crucial reaction intermediate for superior electrocatalytic performance.