The ZnO nanoparticles were synthesized using sodium lignosulfonate as a stabilizing agent and sodium hydroxide as a precipitation agent. The negatively charged ZnO nanoparticles were deposited onto cellulose paper through a layer-by-layer approach.

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.

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.

2,2-Pyridylbenzimidazole is used for the first time as nitrogen coordination compound for synthesizing nitrogen-doped carbon catalyst for oxygen reduction reaction (ORR). The as-prepared catalyst exhibits better catalytic activity and stability than commercial carbon supported platinum (Pt/C) catalyst for ORR in alkaline media. Excellent methanol tolerance ability is also demonstrated. We propose that the presence of trace metal residues in this catalyst can profoundly promote ORR.

Highly active non-precious metal catalysts based on nitrogen-doped carbon xerogel (NCX) for the oxygen reduction reaction (ORR) is prepared with resorcinol(R)-formaldehyde (F) resin as carbon precursor and NH3 as nitrogen source. NCX samples doped with various transition metal species are investigated to elucidate the effect of transition metals on the structure and ORR activity of the products. As-prepared NCX catalysts with different metals are characterized using nitrogen-adsorption analysis, X-ray diffractometry, X-ray photoelectron spectroscopy, and Raman spectroscopy. The structural properties and ORR activities of the catalysts are altered by addition of different metals, and NCX doped with iron exhibits the best ORR activity. Metal doping evidently promotes the formation of more micropores and mesopores. Raman and XPS studies reveal that iron, cobalt, and nickel can increase pyridinic-N contents and that iron can catalyse the formation of graphene structures and enhance quaternary-N contents. Whereas the total N-content does not determine ORR activity, Metal-N4/C-like species generated from the interaction of the metals with nitrogen and carbon atoms play important roles in achieving high ORR activity.

N-doped carbon catalysts have attracted great attention as potential alternatives to expensive Pt-based catalysts used in fuel cells. Herein, an ordered hierarchically porous carbon codoped with N and Fe (Fe-NOHPC) is prepared by an evaporation-induced self-assembly process followed by carbonization under ammonia. The soft template and Fe species promote the formation of the porous structure and facilitate the oxygen reduction reaction (ORR).The catalyst possesses an ordered hierarchically porous structure with a large surface area (1172.5 m(2) g(-1) ) and pore volume of 1.03 cm(3) g(-1) . Compared to commercial 20% Pt/C, it exhibits better ORR catalytic activity and higher stability as well as higher methanol tolerance in an alkaline electrolyte, which demonstrates its potential use in fuel cells as a nonprecious cathode catalyst. The N configuration, Fe species, and pore structure of the catalysts are believed to correlate with its high catalytic activity.

Nitrogen-doped carbon electrocatalyst with hierarchically porous structure displays excellent catalytic activity. More prominently, the catalyst presents superior stability as well as tolerance of methanol and SO2 to the Pt/C catalysts in 0.5 M H2SO4.

A novel non-platinum oxygen reduction reaction (ORR) catalyst was synthesised by the pyrolysis of carbon-supported vitamin B12 under ammonia atmosphere. The resultant catalyst was characterised by transmission electron microscopy (TEM), scanning TEM (STEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses. Results demonstrated that the catalyst had a spherical structure. XPS revealed that the nitrogen configuration was changed after pyrolysis, and nitrogen species played a key role in catalysing the ORR. The catalyst exhibited an enhanced ORR activity than commercial 20% Pt/C in alkaline media. The catalyst had an electron transfer number of 3.9, which was very close to the ideal theoretical value of 4. Moreover, the catalyst displayed superior methanol tolerance to Pt/C in alkaline medium, demonstrating its potential application as a cost-effective catalyst for direct methanol alkaline fuel cells.