A highly efficient electrocatalyst for oxygen reduction reaction: phosphorus and nitrogen co-doped hierarchically ordered porous carbon derived from an iron-functionalized polymer

Heteroatom-doped carbon materials have shown respectable activity for the oxygen reduction reaction (ORR) in alkaline media. However, the performances of these materials are not satisfactory for energy conversion devices, such as fuel cells. Here, we demonstrate a new type of phosphorus and nitrogen co-doped hierarchically ordered porous carbon (PNHOPC) derived from an iron-functionalized mesoporous polymer through an evaporation-induced self-assembly process that simultaneously combines the carbonization and nitrogen doping processes. The soft template and the nitrogen doping process facilitate the formation of the hierarchically ordered structure for the PNHOPC. The catalyst possesses a large surface area (1118 cm(2) g(-1)) and a pore volume of 1.14 cm(3) g(-1). Notably, it exhibits excellent ORR catalytic performance, superior stability and methanol tolerance in acidic electrolytes, thus making the catalyst promising for fuel cells. The correlations between the unique pore structure and the nitrogen and phosphorus configuration of the catalysts with high catalytic activity are thoroughly investigated

Zn electrode with a layer of nanoparticles for selective electroreduction of CO2 to formate in aqueous solutions

Developing inexpensive and non-toxic electrocatalysts that can reduce CO2 to formate with high selectivity and stability as well as high current densities is an important step for a sustainable carbon cycle. Electrocatalysts that show the highest faradaic efficiency for formate, such as Pb and Hg, are toxic or expensive and have low current densities. Bulk Zn is a cheap metal that has historically been identified to be a CO2 to CO conversion catalyst. In this work, we introduce a novel Zn electrode with a layer of nanoparticles that exhibit high performance toward CO2 electrochemical reduction to produce formate in aqueous solution. The maximum faradaic efficiency for formate production of over 87% is achieved with a formate partial current density of 12.8 mA cm(-2), which are almost 8 times higher than that of bulk Zn foil and 17 times higher than that of bulk Zn foil, respectively. The improvement in catalytic performance is attributed to the catalytically active facets and special surface structure of polycrystalline Zn formed during reduction of polycrystalline ZnO. The catalyst shows no obvious performance deterioration during the 14 h continuous CO2 reduction

Proton exchange membrane fuel cells with chromium nitride nanocrystals as electrocatalysts

Polymer electrolyte membrane fuel cells (PEMFCs) are energy conversion devices that produce electricity from a supply of fuel, such as hydrogen. One of the major challenges in achieving efficient energy conversion is the development of cost-effective materials that can act as electrocatalysts for PEMFCs. In this letter, we demonstrate that, instead of conventional noble metals, such as platinum, chromium nitride nanocrystals of fcc structure exhibit attractive catalytic activity for PEMFCs. Device testing indicates good stability of nitride nanocrystals in low temperature fuel cell operational environment

Template-assisted synthesis of hierarchically porous Co3O4 with enhanced oxygen evolution activity

Oxygen evolution reaction (OER) is one of the most important reactions in the energy storage devices such as metal air batteries and unitized regenerative fuel cells (URFCs). However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium (SDBS) assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction (OER). Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method (noted as Co3O4-T) and commercial IrO2 catalyst for OER in 0.1 M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions. (C) 2015 Science Press and Dalian Institute of Chemical Physics. All rights reserved

Preparation of Ir0.4Ru0.6MoxOy for oxygen evolution by modified Adams' fusion method

A novel anodic electrocatalyst Ir0.4Ru0.6MoxOy for solid polymer electrolyte (SPE) water electrolysis is prepared by the modified Adams' fusion method. The XRD, ICP, and BET are employed to determine the physical characteristics of Ir0.4Ru0.6MoxOy and Ir0.4Ru0.6O2, and the electrochemical properties of the electrocatalysts are examined by cyclic voltammetry (CV) in 0.5 M H2SO4. The results show that Ir0.4Ru0.6MoxOy has much smaller particle size, larger specific surface areas and active surface area compared with Ir0.4Ru0.6O2. The results of single cell performance and the electrochemical impedance spectroscopy (EIS) tests also prove that Ir0.4Ru0.6MoxOy has higher performance than Ir0.4Ru0.6O2. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved

Bismuth nanodendrites as a high performance electrocatalyst for selective conversion of CO2 to formate

A nanostructured bismuth dendrite catalyst was designed and directly grown on treated carbon paper using a novel electrochemical deposition method. It exhibits an excellent performance for efficient CO2 reduction to formate, achieving a maximum faradaic efficiency of 96.4% with a current density of 15.2mA cm(-2). The catalyst is shown to be stable during 10 h of continuous electrolysis