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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]

Biodiversity endows similar species with subtle differences in composition, microstructure, and surface chemistry, making biomass a promising precursor to control the resulting active structure for heterocatalysis. Here, it is shown that Tremella fuciformis (Tfu), possessing an abundant porous structure and favorable metal affinity, is favorably serves as a precursor for confining uniform metal nanoparticles, by comparing the chemical characteristics of six varieties of agarics. The modest size of Co in the Tfu derived composite, Co@NPC‐Tfu (NPC = N, P co‐doped carbon), is suitable for in situ semi‐oxidation during oxygen evolution reaction (OER), forming a stable core‐shell structure of Co3O4@Co. Thus, Co@NPC‐Tfu can be used as a state‐of‐the‐art electrocatalyst for OER with an overpotential of 213.6 ± 4.1 mV at 10 mA cm−2, and a significant turnover frequency of 3.21 s−1 at 300 mV, benefitting from the optimum trade‐off between the atom utilization and electrical conductivity. Operando spectroscopy and theoretical calculations unveil the occupied state modulation of the robust carbon‐bonded POx groups, which optimizes the intermediate adsorption to accelerate OER kinetics. Moreover, Tfu derived Ni@NPC‐Tfu can be also prepared as a high‐performance hydrogen evolution reaction electrocatalyst, which can be utilized for efficient overall water splitting coupled with Co@NPC‐Tfu. [ABSTRACT FROM AUTHOR]

Cobalt imidazolate frameworks are classical electrocatalysts for the oxygen evolution reaction (OER) but suffer from the relatively low activity. Here, a non‐3d metal modulation strategy is presented for enhancing the OER activity of cobalt imidazolate frameworks. Two isomorphous frameworks [Co4(MO4)(eim)6] (M=Mo or W, Heim=2‐ethylimidazole) having Co(eim)3(MO4) units and high water stabilities were designed and synthesized. In different neutral media, the Mo‐modulated framework coated on a glassy carbon electrode shows the best OER performances (1 mA cm−2 at an overpotential of 210 mV in CO2‐saturated 0.5 m KHCO3 electrolyte and 2/10/22 mA cm−2 at overpotential of 388/490/570 mV in phosphate buffer solution) among non‐precious metal catalysts and even outperforms RuO2. Spectroscopic measurements and computational simulations revealed that the non‐3d metals modulate the electronic structure of Co for optimum reactant/product adsorption and tailor the energy of rate‐determining step to a more moderate value. Non‐3D for 3D: Introducing non‐3d metal oxide units into a cobalt imidazolate framework results in the drastic enhancement of electrocatalytic performance of the oxygen evolution reaction in neutral media. [ABSTRACT FROM AUTHOR]