Engineering pore-size distribution of metal-loaded carbon catalysts by in situ cavitation for boosting electrochemical mass transfer.

In addition to highly active catalytic sites, mass transfer, especially diffusion of the reactant/product also play important roles in supported electrocatalyst systems. However, compared with the morphologies and specific surface areas, the pore structures of the catalyst supports and their influence on catalytic mass transfer have received less attention. Herein, we propose a universal in situ cavitation strategy to regulate the pore size distributions on the metal-loaded carbon through nitro modification on the molecule-based precursors, without significantly changing the electronic structures of the active metal centers. Gas sorption experiments, electrocatalytic measurements and molecular dynamic simulations certified that the increasing mesopore/macropore ratios can remarkably facilitate the diffusion coefficient, enabling improved oxygen evolution kinetics with 71 mV overpotential dropping at 10 mA·cm−2 compared with the nitro-free counterpart. This work demonstrates that the pore size distributions of the catalyst support should be another nonnegligible parameter on boosting the overall electrocatalytic performance. [Display omitted] • Pore-size distribution of carbon support is regulated by an in-situ cavitation. • Increasing mesopore/macropore proportion facilitates the diffusion coefficient. • A high diffusion coefficient improves electrocatalytic oxygen evolution kinetic. • The pore engineering is compatible with general electronic regulation strategies. [ABSTRACT FROM AUTHOR]