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.