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Replacing platinum as an oxygen reduction catalyst is an important scientific and technological challenge. Herein we report a simple synthesis of a complex carbon with very good oxygen reduction reaction (ORR) activity at pH 13. Pyrolysis of magnesium nitrilotriacetate yields a carbon with hierarchical micro/meso/macro porosity, resulting from in situ templating by spontaneously forming MgO nanoparticles and from etching by pyrolysis gases. The mesopores are lined with highly graphitic shells. The high ORR activity is attributed to a good balance between high specific surface area and mass transport through the hierarchical porosity, and to improved electronic conductivity through the graphitic shells. This novel carbon has a high surface area (1320 m(2) g(-1) ), and high nitrogen content for a single precursor synthesis (∼6 %). Importantly, its synthesis is both cheap and easily scalable.

Solid oxide fuel cells (SOFCs) have appeared as a promising technology for a wide variety of potential commercial applications to lessen the urgency of energy shortage and environmental pollution associated with using conventional fossil fuels. Among the worldwide SOFCs research activities, the progress of SOFCs fed with hydrocarbon fuels that contain trace amount of H 2 S is one of the most important research directions. Thereby, it becomes crucial to design novel electrode materials with enhanced catalytic activity, stability and tolerances to carbon deposition and sulfur poisoning. Lasubstituted SrTiO 3 (LST) based perovskite anodes have been widely investigated because of their high electronic conductivity in reducing atmospheres, excellent dimensional and chemical stability upon redox cycling and outstanding sulfur and coking tolerances. In this review paper, we will describe the development of LST-based anode materials for SOFCs in recent years. The synthesis, structure and fuel cell performance of the doped LST and LST-based composite anode materials are summarized in detail. The mechanism of H 2 S-induced enhancement effect for electrochemical reactions on the LST-based anode materials is explored. The challenges related to the future developments of LST-based anode materials for SOFCs are also discussed.

wileyonlinelibrary.comelectrical power each year, energy conversion effi ciency is, therefore, a key factor in reducing the environmental impacts and utilizing the valuable natural resources responsibly. In comparison with the conventional electricity generation methods, fuel cells are perhaps among the most promising alternatives, showing excellent environmental-friendliness, high efficiency and reasonable energy density. [1][2][3][4] Practically, in each type of fuel cells, the rate-determining step is always believed to be the oxygen reduction reaction (ORR), due to the lack of the affordable yet high-performance electrocatalyst. [5][6][7][8] For instance, the high cathodic overpotential loss is a major factor in undermining the performances of the state-of-the-art solid oxide fuel cells (SOFCs) at temperatures between 500 and 700 °C. [ 7 ] Similarly, in the researches on proton exchange membrane fuel cells (PEMFCs), desperate efforts are devoted to the development of highly active ORR catalysts to replace the stateof-the-art carbon supported platinum. [ 8 ] Indeed, the noble metal contained materials, including Pt and its alloys, [ 8 ] were proven to be superior ORR catalysts. However, the problem is the very limited precious metals resources on this planet for large scale commercialization of the electrochemical devices referred above, not to mention their high prices and the ease of suffering degradations due to poisoning and/or leaching of metals. Alternatively, non-precious metals and compounds [ 9,10 ] as well as metal-free materials, [11][12][13] e.g., organometallic compounds and heteroatom-doped carbon materials, were developed that showed good ORR performances. In spite of that, the gradual deactivations of these catalysts during the stability test were commonly observed, and the complicated synthesis protocols posted another challenge regarding the practical application. Recently, studies on perovskite oxides, [4][5][6][7][14][15][16][17][18][19][20][21][22][23][24] such as La 0.5 Sr 0.5 CoO 2.91 (LSC), [ 16 ] Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF), [ 17,18 ] PrBa 0.5 Sr 0.5 Co 2-x Fe x O 5+δ (PBSCF), [ 19 ] and Sr 0.95 Ag 0.05 Nb 0.1 Co 0.9 O 3-δ , [ 20 ] offered a new dimension in tackling these challenges. Specifi cally, the double perovskite catalyst with a general formula of AA′B 2 O 5+δ demonstrated much higher oxygen ion diffusion rate and surfaceexchange coeffi cient relative to the ABO 3 -type, contributing to a faster ORR. [ 4,7,[19][20][21][22][23][24][25][26][27][28][29] The effi ciencies of a number of electrochemical devices (e.g., fuel cells and metal-air batteries) are mainly governed by the kinetics of the oxygen reduction reaction (ORR). Among all the good ORR catalysts, the partially substituted double perovskite oxide (AA′B 2 O 5+δ ) has the unique layered structure, providing a great fl exibility regarding the optimization of its electronic structures and physicochemical properties. Here, it is demonstrated that the double perovskite oxide, i.e., NdBa 0.75 Ca 0.25 Co 1.5 Fe 0....

Pyrolitic self-templating synthesis is an effective method for creating hierarchically porous N-doped carbons.