Polyvinylpyrrolidone-Assisted Hydrothermal Synthesis of CuCoO₂ Nanoplates with Enhanced Oxygen Evolution Reaction Performance

Abstract

Tuning size and morphology and exploiting new catalytic materials are several important strategies commonly used to develop highly efficient oxygen evolution reaction (OER) electrocatalysts. In this work, we report the synthesis of CuCoO 2 (CCO) nanoplates through a facile one-step polyvinylpyrrolidone-assisted hydrothermal process. The influence of hydrothermal reaction parameters, including the precursor composition, reaction temperature and duration, on the morphology, size and crystal phase of CCO crystals has been investigated in detail. In addition, X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) have been used to comprehensively characterize CCO's crystal structure, morphology, composition and chemical states of elements. Furthermore, the electrocatalytic performance of CCO nanoplates toward the OER is studied and compared to that of CCO micrometer-sized crystals. The CCO nanoplates only require a low overpotential of 390 mV to attain an anodic current density 10 mA cm −2 in alkaline solution, and show comparatively fast OER kinetics with a Tafel slope of 70 mV dec −1 and reasonably good long-term catalytic stability, substantially outperforming CCO microcrystals, which highlights the importance of size and morphology of CCO for use in OER electrocatalysis.

Disclosing the Structural, Electronic, Magnetic, and Morphological Properties of CuMnO2: A Unified Experimental and Theoretical Approach

“…A deep analysis of FE-SEM reported by Fu et al indicates that hexagonal prisms obtained at 180 °C can be related to the nanoplate-like architecture. In addition, other Cu-based delafossite materials show nanoplate-like morphology ,− as observed for CuMnO 2 , confirming that such architecture is characteristic of this material class.…”

“…Delafossite materials have attracted remarkable attention recently due to their potential applications as multiferroic, oxygen storage devices, photovoltaic and photocatalytic semiconductors, hydrogen photocathodes, and environmentally friendly platforms, among others. − This class of compounds can be described by a general formula ABO 2 , with A and B being transition metal cations. The crystal structure usually consists of hexagonal delafossite, where the monovalent A + cations are linearly coordinated with two O ions and the parallel O–A–O chains connect edge-sharing [BO] 6 octahedrons formed by B 3+ cations …”

Large-Scale Fabrication of Hollow Pt3Al Nanoboxes and Their Electrocatalytic Performance for Hydrogen Evolution Reaction

“…As a comparison, the HER activity of commercial Pt/C (20 wt % Pt) catalysts was also measured. The overpotential needed to deliver a current density of 10 mA cm –2 (i.e., η 10 ) has been widely used as a performance indicator of electrocatalysts. ,, As shown in Figure a, the hollow Pt 3 Al nanoboxes need a η 10 of 38 mV to afford the HER catalytic current density of 10 mA cm –2 , lower than that of the commercial Pt/C nanoparticles (η 10 = 52 mV). The HER reaction kinetics are analyzed by the Tafel plot (Figure b).…”

Cobalt Nanoparticles Embedded in N, S Co‐Doped Carbon towards Oxygen Reduction Reaction Derived by in situ Reducing Cobalt Sulfide

“…Interestingly, with the introducing of sulfur species and increase of its content, the shift to lower binding energy of pyridinic N, pyrrolic N and graphitic N species can be observed in Figure b, meaning that electronic cloud gets denser, which comes from sulfur species. Meanwhile, the high resolution O 1s spectra of CoSMe‐X‐800 samples (Figure c) show three different peaks: 531.3 eV (lattice O), 532.3 eV (C=O) and 533.3 eV (OH−) . Clearly, when introducing the sulfur resources, the peaks of all the O species shift towards lower binding energy, indicating the electron transfer from sulfur species to O species, which can be confirmed by XPS spectra of S 2p.…”