Yanbing Zhang

Three-dimensional and stable polyaniline-grafted graphene hybrid materials for supercapacitor electrodes

A novel route is introduced to synthesize hierarchical polyaniline-grafted reduced graphene oxide (rGO) hybrid materials by polyaniline nanorods covalently bonded on the surface of rGO. Aminophenyl groups were initially grafted on rGO via diazonium treatment. Then the PANI nanorods were aligned vertically on rGO to construct a three-dimensional (3D) structure. The 3D structure could shorten the electronic transmission path and form abundant space for electrolyte ions. The hybrid materials fabricated as supercapacitor electrodes exhibited a maximal specific capacitance of 1045.51 F g−1, and the energy density (E) could achieve an upper value of 8.3 W h kg−1 at the current density of 0.2 A g−1 simultaneously. Such highly stable three-dimensional structural materials are very promising for the next generation of high-performance electrochemical supercapacitors.

Fabrication of Mn-FeOx/CNTs Catalysts for Low-Temperature NO Reduction with NH3

Mn-FeOx/carbon nanotubes (CNTs) catalysts were firstly prepared via simple incipient wetness method and used for low-temperature selective catalytic reduction (SCR) of NO with NH3. The structure and surface properties of the catalysts were characterized by N2 sorption, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H2-TPR). It was found that Mn-FeOx/CNTs catalyst exhibited excellent low-temperature SCR activity and SO2 resistance. XRD patterns revealed that metal oxides catalysts were possessed of amorphous structure. FESEM and TEM images showed that metal oxides catalysts were successfully supported on CNTs. The XPS results indicated that the obtained catalyst presented high Mn4+/Mn3+ and OS/(OS + OL) ratios. The H2-TPR profiles showed that Mn-FeOx/CNTs catalyst possessed better low-temperature reducibility. Besides, the obtained catalyst exhibited better SO2 resistance.

Fabrication of Mn–CeOx/CNTs catalysts by a redox method and their performance in low-temperature NO reduction with NH3

Highly active Mn–CeOx/CNTs catalysts were first fabricated by a novel redox method, and a formation mechanism was proposed. The as-obtained catalyst possessed an amorphous structure, and high Ce3+/(Ce3+ + Ce4+) and Oα/(Oα + Oβ) ratios, which endowed it with 52.2–98.4% NO conversion at a weight hourly space velocity of 210 000 ml gcat−1 h−1.

MnO2 catalysts uniformly decorated on polyphenylene sulfide filter felt by a polypyrrole-assisted method for use in the selective catalytic reduction of NO with NH3

A manganese dioxide (MnO2)/polypyrrole (PPy) nanocoating was uniformly decorated on the surface of polyphenylene sulfide (PPS) filter felt via an in situ synthesis method to fabricate a catalytic filter material. The pyrrole functioned as a dispersant for the MnO2 catalysts and the PPy generated acted as a binder to adhere the MnO2 catalysts and filter felt together. The catalytic filter material obtained, had a high adhesive strength between that of the MnO2/PPy nanocoating and the PPS filter felt, and was used for the selective catalytic reduction of nitric oxide (NO) with ammonia under model conditions without any sulfur dioxide or water vapor in the gas. More than 70% conversion of NO was achieved at 160–180 °C at a high space velocity of 38 000 h−1.

Fabrication and formation mechanism of Ce2O3–CeO2–CuO–MnO2/CNTs catalysts and application in low-temperature NO reduction with NH3

Ce2O3–CeO2–CuO–MnO2/CNTs catalysts were synthesized via a redox strategy, and presented 58–85% NO conversion at 80–180 °C. The 6% Ce2O3–CeO2–CuO–MnO2/CNTs catalyst displayed the optimal activity, which may be owing to the generation of amorphous mixed metal-oxide catalysts, and higher contents of Ce3+ and surface oxygen (Oy). The formation mechanism of the catalysts was proposed.