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Precise regulation of the electronic states of catalytic sites through molecular engineering is highly desired to boost catalytic performance. Herein, a facile strategy was developed to synthesize efficient oxygen reduction reaction (ORR) catalysts, based on mononuclear iron phthalocyanine supported on commercially available multi‐walled carbon nanotubes that contain electron‐donating functional groups (FePc/CNT‐R, with "R" being −NH2, −OH, or −COOH). These functional groups acted as axial ligands that coordinated to the Fe site, confirmed by X‐ray photoelectron spectroscopy and synchrotron‐radiation‐based X‐ray absorption fine structure. Experimental results showed that FePc/CNT‐NH2, with the most electron‐donating −NH2 axial ligand, exhibited the highest ORR activity with a positive onset potential (Eonset=1.0 V vs. reversible hydrogen electrode) and half‐wave potential (E1/2=0.92 V). This was better than the state‐of‐the‐art Pt/C catalyst (Eonset=1.00 V and E1/2=0.85 V) under the same conditions. Overall, the functionalized FePc/CNT‐R assemblies showed enhanced ORR performance in comparison to the non‐functionalized FePc/CNT assembly. The origin of this behavior was investigated using density functional theory calculations, which demonstrated that the coordination of electron‐donating groups to FePc facilitated the adsorption and activation of oxygen. This study not only demonstrates a series of advanced ORR electrocatalysts, but also introduces a feasible strategy for the rational design of highly active electrocatalysts for other proton‐coupled electron transfer reactions. [ABSTRACT FROM AUTHOR]

Although carbon itself acts as a catalyst in various reactions, the classical carbon materials (e.g., activated carbons, carbon aerogels, carbon black, carbon fiber, etc.) usually show low activity, stability, and oxidation resistance. With the recent availability of nanocarbon catalysts, the application of carbon materials in catalysis has gained a renewed momentum. The research is concentrated on tailoring the surface chemistry of nanocarbon materials, since the pristine carbons in general are not active for heterogeneous catalysis. Surface functionalization, doping with heteroatoms, and creating defects are the most used strategies to make efficient catalysts. However, the nature of the catalytic active sites and their role in determining the activity and selectivity is still not well understood. Herein, the types of active sites reported for several mainstream nanocarbons, including carbon nanotubes, graphene‐based materials, and 3D porous nanocarbons, are summarized. Knowledge about the active sites will be beneficial for the design and synthesis of nanocarbon catalysts with improved activity, selectivity, and stability. [ABSTRACT FROM AUTHOR]

Abstract: The development of highly selective, chemically stable and moisture‐resistant adsorbents is a key milestone for gas separation. Porous carbons featured with random orientation and cross‐linking of turbostratic nanodomains usually have a wide distribution of micropores. Here we have developed a thermoregulated phase‐transition‐assisted synthesis of carbon nanoplates with more than 80 % sp2 carbon, unimodal ultramicropore and a controllable thickness. The thin structure allows oriented growth of carbon crystallites, and stacking of crystallites in nearly parallel orientation are responsible for the single size of the micropores. When used for gas separation from CH4, carbon nanoplates exhibit high uptakes (5.2, 5.3 and 5.1 mmol g−1) and selectivities (7, 71 and 386) for CO2, C2H6 and C3H8 under ambient conditions. The dynamic adsorption capacities are close to equilibrium uptakes of single components, further demonstrating superiority of carbon nanoplates in terms of selectivity and sorption kinetics. [ABSTRACT FROM AUTHOR]