Ordered Nanostructure Enhances Electrocatalytic Performance by Directional Micro-Electric Field

Abstract

Designing high-efficiency catalyst is at the heart of a transition to future renewable energy systems. Great achievements have been made to optimize thermodynamics to reduce energetic barriers of the catalytic reactions. However, little attention has been paid to design catalysts to improve kinetics to enrich the local concentration of reactant molecules surrounding electrocatalysts. Here, we find that well-designed nanocatalysts with periodic structures can optimize kinetics to accelerate mass-transport from bulk electrolyte to the catalyst surface, leading to the enhanced catalytic performance. This achievement stems from regulation of the surface reactant flux due to the gradient of the microelectric field directing uniformly to the nearest catalyst on ordered pattern, so that all of the reactant molecules are utilized sufficiently for reactions, enabling the boost of the electrocatalytic performance. This novel concept is further confirmed in various catalytic systems and nanoassemblies, such as nanoparticles, nanorods, and nanoflakes.

Hidden Mechanism Behind the Roughness‐Enhanced Selectivity of Carbon Monoxide Electrocatalytic Reduction

“…As shown in Figure 1, adsorption, desorption, diffusion, reduction of CO, as well as the accompanied HER are included. Specially, since the curvature of HC sites on the electrode surface can lead to an enhanced local electric field, the local‐field‐induced directional mass transfer is also taken into account [28–30] . The reaction‐diffusion equations (RDE) for CORR on multisite electrocatalysts surface are derived as follows (Details in supplementary information, SI) [Eqs.…”

“…Here, k B is the Boltzmann constant and T the temperature. The effective interaction potential between local electric field and chemical species is chosen as Gaussian‐like , [28] where α is the interaction strength, u 0 denotes the intensity of electric field on an isolated single HC site located at r site , and r 0 is the characteristic length [28, 30] . Since CO can be polarized by the local electric field and be attracted to HC sites, we take α CO <0 to describe such attraction.…”

“…The effective interaction potential between local electric field and chemical species is chosen as Gaussian-like V r ð Þ ¼ P site aqu 0 expðÀ r À r site j j 2 = r 2 0 Þ À Á , [28] where a is the interaction strength, u 0 denotes the intensity of electric field on an isolated single HC site located at r site , and r 0 is the characteristic length. [28,30] Since CO can be polarized by the local electric field and be attracted to HC sites, we take a CO < 0 to describe such attraction. On the contrary, the adsorbed OH À would be pushed away from HC sites, and consequently a OH > 0.…”

Construction of Nitrogen-Doped Carbon Nanosheets for Efficient and Stable Oxygen Reduction Electrocatalysis

“…The literature reveals that noble metal-based catalysts [especially platinum (Pt)] are featured with high catalytic activity towards ORR. [6][7][8] However, their extended application is hampered by their scarcity, high cost and poor long-term stability. Therefore, extensive research efforts have been devoted to finding appealing alternatives to Pt-based electrocatalysts.…”

Hidden Mechanism Behind the Roughness‐Enhanced Selectivity of Carbon Monoxide Electrocatalytic Reduction

“…Specially, since the curvature of HC sites on the electrode surface can lead to an enhanced local electric field, the local-field-induced directional mass transfer is also taken into account. [28][29][30] The reaction-diffusion equations (RDE) for CORR on multisite electrocatalysts surface are derived as follows (Details in supplementary information, SI) [Eqs. (1a)-(1b)].…”