N-doped Porous Carbon Materials Research Articles

Fe/Fe3 C/N-Doped Carbon Materials from Metal-Organic Framework Composites as Highly Efficient Oxygen Reduction Reaction Electrocatalysts.

A series of Fe/Fe3 C-containing N-doped porous carbon materials (Fe/NC) were prepared by pyrolyzing composites that contained a metal-organic framework (MIL-88c-Fe) with dicyandiamide. The Fe/NC obtained at 800 °C (Fe/NC800) showed comparable onset potential and kinetics to that of the commercial Pt/C catalyst in catalyzing the oxygen reduction reaction (ORR). Further measurements suggested that it has better durability and much higher methanol tolerance than Pt/C. Acid leaching was performed to reveal the critical role of Fe-containing sites in ORR catalysis.

Hierarchical Metal-Free Nitrogen-Doped Porous Graphene/Carbon Composites as an Efficient Oxygen Reduction Reaction Catalyst.

Hierarchical nitrogen-doped porous graphene/carbon (NPGC) composites were fabricated by a simple and nontemplate method. The morphology characterizations demonstrate that reduced graphene oxide was successfully coated by the carbon derived from glucose, and a well-organized and interpenetrated hierarchical porous structure of NPGC was formed after pyrolysis at 950 °C. Notably, the prepared material, denoted as NPGC-950, has superlarge specific surface area (1510.83 m(2) g(-1)) and relatively high content percentage of pyridinic and graphitic nitrogen. As an efficient metal-free electrocatalyst, NPGC-950 exhibits a high onset potential (0.91 V vs RHE) and a nearly four-electron pathway for oxygen reduction reaction in alkaline solution as well as stronger methanol tolerance and better long-term durability than commercial Pt/C. In view of these excellent features, the obtained hierarchical N-doped metal-free porous carbon material is a promising catalyst for oxygen reduction reaction and could be widely applied in industry.

Shrimp-shell derived carbon nanodots as carbon and nitrogen sources to fabricate three-dimensional N-doped porous carbon electrocatalysts for the oxygen reduction reaction.

Development of cheap, abundant and metal-free N-doped carbon materials as high efficiency oxygen reduction electrocatalysts is crucial for their practical applications in future fuel cell devices. Here, three-dimensional (3D) N-doped porous carbon (NPC) materials have been successfully developed by a simple template-assisted (e.g., SiO2 spheres) high temperature pyrolysis approach using shrimp-shell derived N-doped carbon nanodots (N-CNs) as carbon and nitrogen sources obtained through a facile hydrothermal method. The shrimp-shell derived N-CNs with a product yield of ∼ 5% possess rich surface O- and N-containing functional groups and small nanodot sizes of 1.5-5.0 nm, which are mixed with surface acidification treated SiO2 spheres with an average diameter of ∼ 200 nm in aqueous solution to form a N-CNs@SiO2 composite subjected to a thermal evaporation treatment. The resultant N-CNs@SiO2 composite is further thermally treated in a N2 atmosphere at different pyrolysis temperatures, followed by acid etching, to obtain 3D N-doped porous carbon (NPC) materials. As electrocatalysts for oxygen reduction reaction (ORR) in alkaline media, the experimental results demonstrate that 3D NPC obtained at 800 °C (NPC-800) with a surface area of 360.2 m(2) g(-1) exhibits the best ORR catalytic activity with an onset potential of -0.06 V, a half wave potential of -0.21 V and a large limiting current density of 5.3 mA cm(-2) (at -0.4 V, vs. Ag/AgCl) among all NPC materials investigated, comparable to that of the commercial Pt/C catalyst with an onset potential of -0.03 V, a half wave potential of -0.17 V and a limiting current density of 5.5 mA cm(-2) at -0.4 V. Such a 3D porous carbon ORR electrocatalyst also displays superior durability and high methanol tolerance in alkaline media, apparently better than the commercial Pt/C catalyst. The findings of this work would be valuable for the development of low-cost and abundant N-doped carbon materials from biomass as high performance metal-free electrocatalysts.

Preparation of N-doped microporous carbon nanospheres by direct carbonization of as-prepared mesoporous silica nanospheres containing cetylpyridinium bromide template

N-doped microporous carbon nanospheres (MCNs) are prepared directly from the as-prepared mesoporous silica nanospheres (MSNs) with a disordered pore structure by a new, simple and direct carbonization method. The as-prepared MSNs containing cetylpyridinium bromide (CTPB) template are effective for direct carbonization. Neither MSN with a two-dimensional hexagonal pore symmetry nor MSN with cetyltrimethylammonium bromide (CTAB) template is effective for this new method. Thus, this method is very cost-effective and environmentally benign. Furthermore, N-doping into the carbon matrix naturally occurrs during the carbonization process, because of the presence of pyridinium N atoms in the CTPB template. The N-doped MCN material is a good sorbent material for CO2 adsorption owing to the Lewis basic sites of N atoms as well as good microporosity. The low surface coverage isosteirc heat of CO2 adsorption (Qst) is calculated by the Clausius–Clapeyron equation using the data obtained at 273 and 298 K, and the calculated value of Qst is 58.4 kJ mol−1. This value is relatively very high compared to the other N-doped porous carbon materials. Both the Lewis basic sites of N atoms and uniform microporosity in the N-doped MCNs are responsible for this high value.

N-doped porous carbon derived from biomass as an advanced electrocatalyst for aqueous aluminium/air battery

A metal-free N-doped porous carbon (N-PC) derived from tapioca was fabricated and used as an enhanced electrocatalyst for aqueous metal/air battery. The electrochemical performance of N-doped porous carbon material as well as undoped porous carbon (PC) was studied by galvanostatic discharge measurements and steady-state linear polarization. Because of the existence of doping N atom, the N-PC exhibits a nice electrocatalytic activity in alkaline solutions. In addition, the N-PC loaded air electrode performs a high discharge voltage of 1.36 V at a current density of 50 mA cm−2 in aluminium/air battery, which should be attributed to highly efficient, new and active sites created by N doping. N-PC could be used as an advanced electrocatalyst for high power aluminium/air battery.

Pig bones derived N-doped carbon with multi-level pores as electrocatalyst for oxygen reduction

In this work, a N-doped highly porous carbon material with multi-level pores and high activity for oxygen reduction reaction (ORR) is successfully prepared by carbonizing pig bones instead of separated carbon/nitrogen-containing and template precursors. The N-doped porous carbon material has high specific surface area of ca. 562.6 m2 g−1. Due to its high surface area and N-doped active sites, the ORR activity of obtained carbon in alkaline media is higher than that of commercial Pt/C catalyst (10 wt.%). In addition, it shows a higher methanol tolerance than Pt/C catalyst and long term-operating stability, rendering it as promising ORR catalyst material for fuel cells.

N-doped porous carbon material made from fish-bones and its highly electrocatalytic performance in the oxygen reduction reaction

N-doped porous carbon material derived of fish bones showed excellent catalytic activity towards oxygen reduction reaction in alkaline medium, as well as long-term stability.

Chicken bone-derived N-doped porous carbon materials as an oxygen reduction electrocatalyst

In this work, a low-cost, N-doped, porous carbon material with high surface area is synthesized by carbonizing chicken bones. The N-doped porous carbon material has high specific surface area. Brunauer-Emmett-Teller (BET) surface area of obtained carbon material is ca. 769m2g−1 with a pore size distribution in the range of 1–4nm. Compared to a commercial Pt/C (10 wt%) catalyst, oxygen reduction in alkaline medium on the synthesized carbon material exhibits comparable electrocatalytic activity, long term-operating durability and excellent CH3OH tolerance, rendering it as a potential alternative to Pt-based catalysts.

Preparation and carbon dioxide uptake capacity of N-doped porous carbon materials derived from direct carbonization of zeolitic imidazolate framework

The preparation, characterization and CO2 uptake performance of N-doped porous carbon materials and composites derived from direct carbonization of ZIF-8 under various conditions are presented for the first time. It is found that the carbonization temperature has remarkable effect on the compositions, the textural properties and consequently the CO2 adsorption capacities of the ZIF-derived porous materials. Changing the carbonization temperature from 600 to 1000°C, the composites and the resulting porous carbon materials possess a tuneable nitrogen content in the range of 7.1–24.8wt%, a surface area of 362–1466m2g−1 and a pore volume of 0.27–0.87cm3g−1, where a significant proportion of the porosity is contributed by micropores. These N-doped porous composites and carbons exhibit excellent CO2 uptake capacities up to 3.8mmolg−1 at 25°C and 1bar with a CO2 adsorption energy up to 26kJmol−1 at higher CO2 coverages. The average adsorption energy for CO2 is one of the highest ever reported for any porous carbon materials. Moreover, the influence of textural properties on CO2 capture performance of the resulting porous adsorbents has been discussed, which may pave the way to further develop higher efficient CO2 adsorbent materials.

One-step scalable preparation of N-doped nanoporous carbon as a high-performance electrocatalyst for the oxygen reduction reaction

N-doped porous carbon materials have been prepared by a simple one-step pyrolysis of ethylenediaminetetraacetic acid (EDTA) and melamine in the presence of KOH and Co(NO3)2·6H2O. The combination of the high specific area (1485 m2·g−1), high nitrogen content (10.8%) and suitable graphitic degree results in catalysts exhibiting high activity (with onset and half-wave potentials of 0.88 and 0.79 V vs the reversible hydrogen electrode (RHE), respectively) and four-electron selectivity for the oxygen reduction reaction (ORR) in alkaline medium—comparable to a commercial Pt/C catalyst, but far exceeding Pt/C in stability and durability. Owing to their superb ORR performance, low cost and facile preparation, the catalysts have great potential applications in fuel cells, metal-air batteries, and ORR-related electrochemical industries. Open image in new window