Molecular Engineering toward High‐Crystallinity Yet High‐Surface‐Area Porous Carbon Nanosheets for Enhanced Electrocatalytic Oxygen Reduction

Abstract

Carbon‐based nanomaterials have been regarded as promising non‐noble metal catalysts for renewable energy conversion system (e.g., fuel cells and metal–air batteries). In general, graphitic skeleton and porous structure are both critical for the performances of carbon‐based catalysts. However, the pursuit of high surface area while maintaining high graphitization degree remains an arduous challenge because of the trade‐off relationship between these two key characteristics. Herein, a simple yet efficient approach is demonstrated to fabricate a class of 2D N‐doped graphitized porous carbon nanosheets (GPCNSs) featuring both high crystallinity and high specific surface area by utilizing amine aromatic organoalkoxysilane as an all‐in‐one precursor and FeCl3·6H2O as an active salt template. The highly porous structure of the as‐obtained GPCNSs is mainly attributed to the alkoxysilane‐derived SiOx nanodomains that function as micro/mesopore templates; meanwhile, the highly crystalline graphitic skeleton is synergistically contributed by the aromatic nucleus of the precursor and FeCl3·6H2O. The unusual integration of graphitic skeleton with porous structure endows GPCNSs with superior catalytic activity and long‐term stability when used as electrocatalysts for oxygen reduction reaction and Zn–air batteries. These findings will shed new light on the facile fabrication of highly porous carbon materials with desired graphitic structure for numerous applications.

Synthesis and Aerobic Oxidation Catalysis of Mesoporous Todorokite-Type Manganese Oxide Nanoparticles by Crystallization of Precursors

“…Surface active sites increase with a decrease in particle size but result in a lower degree of crystallinity. Therefore, a trade-off relationship between particle size and catalytic performance (e.g., activity, selectivity, and stability) has been observed in some thermo-, photo-, and electro-catalytic reactions. − In the case of the present β-MnO 2 nanoparticles synthesized by the solid-state transformation method, the reaction rate per surface area for the oxidation of 5-formyl-2-furancarboxylic acid to 2,5-furandicarboxylic acid was lower than that of low-surface-area β-MnO 2 nanorods synthesized by the hydrothermal method, probably due to the low crystallinity . On the other hand, the initial reaction rates of OMS-1 for the aerobic oxidation of 1a linearly increased with the surface area (Figure a).…”

Exploring Durable Single-Atom Catalysts for Proton Exchange Membrane Fuel Cells

“…Despite the low concentration of D2 (8.56%; D1/D2 = 1.8), Fe–N/CNT-2 exhibited much enhanced stability in PEMFC than its counterpart with a low graphitization degree (Figure g). In fact, most M–N–C catalysts reported with commendable stability are featuring highly graphitized carbon support. − From the above examples, it is possible to draw the following conclusions: (1) Fe–N 4 moieties are generally susceptible to oxygen adsorption, and therefore, detection of exclusive D2 site is very challenging due to the complex structural changes during pyrolysis and high sensitivity of Mossbauer spectroscopy. (2) A clear link between the degree of graphitization, D2 content, and fuel cell stability has not been established, possibly because the degradation mechanisms are inter-related.…”

Interface engineering of a GaN/In2O3 heterostructure for highly efficient electrocatalytic CO2 reduction to formate

“…3(d), and Fig. S6, it can be seen that GaN/In2O3@PCNF (0.958) exhibits the smallest ID/IG value of 0.958, compared to PCNF (1.109) and EGaIn@PCNF (1.054), indicating that GaN/In2O3@PCNF exhibits a high degree of graphitic carbon, allowing faster electron transfer in the reaction [45][46][47][48].…”