Hierarchical porosityvialayer-tunnel conversion of macroporous δ-MnO₂nanosheet assemblies

Abstract

This work reports the layer-tunnel conversion of porous dehydrated synthetic alkali-free δ-MnO2 analogs prepared by exfoliation, flocculation, and heat treatment of nanosheets derived from highly crystalline potassium birnessite.

Alternative‐Ultrathin Assembling of Exfoliated Manganese Dioxide and Nitrogen‐Doped Carbon Layers for High‐Mass‐Loading Supercapacitors with Outstanding Capacitance and Impressive Rate Capability

“…Preparation of δ-Manganese Dioxide and Manganese Dioxide/Nitrogen-Doped Carbon: The synthesis of pristine birnessite MnO 2 was followed by the previously reported methods including mixing precursors and a thermal treatment at 800 °C for 24 h. [85][86][87] MnCO 3 and K 2 CO 3 were mixed in IPA at a molar ratio of 40:9 for 5 min at 2000 rpm using a Taylor-Couette flow-based fluid-dynamic reactor (Figure S1, Supporting Information). The fluid-dynamic reactor was comprised of concentric inner and outer cylinders with a gap size of 500 µm and an aspect ratio of Γ = L/d ≈ 20.…”

Bullet-like microstructured nickel ammonium phosphate/graphene foam composite as positive electrode for asymmetric supercapacitors

“…The higher specic energy of Ni(NH 4 ) 2 (PO 3 ) 4 $4H 2 O/60 mg GF//ppAC asymmetric device was obtained to be 52 Wh kg À1 with a specic power of 861 W kg À1 at 1 A g À1 which are much better than the values reported in the literature. 5,[22][23][24][52][53][54][55] The phase angle vs. frequency for the Ni(NH 4 ) 2 (PO 3 ) 4 $4H 2 O/60 mg GF//ppAC asymmetric device in Fig. 9(b) shows the phase angle value of about À83 .…”

Urchin-like hollow SiO2@γ-MnO2 microparticles for the rapid degradation of organic dyes

“…In recent years, the research on g-MnO 2 for AOPs has stimulated an extensive interest in the eld of treatment of organic dyes in wastewater. [32][33][34][35][36] In addition, it is well known that materials with excellent performance depend not only on the crystalline structure and composition but also on the morphology; sometimes, even the inuence of morphology plays a key role in the physicochemical performance. 37,38 To date, MnO 2 microparticles with different morphology, including 0-D nanoparticles, 1-D nanowires, nanorods, nanotubes, 2-D nanosheets, as well as 3-D hierarchical nanostructures, have been successfully prepared.…”