Preparation and characterization of the semiconductor CuMnO2 by sol-gel route

Abstract

Nano crystallites of the crednerite CuMnO 2 are prepared by sol gel method with two step annealing process. The powder heated at 450°C under air flow shows a mixture of CuO, Mn 2 O 3 and Cu x Mn 3 x O 4. However, when calcined at 900°C under N 2 atmosphere, the crednerite CuMnO 2 with a monoclinic structure (space group: C2/m) is obtained. The Raman spectrum shows a single peak at 679 cm 1 as signed to A 1g mode whereas the infrared analysis confirms the linearity of CuO 2 3 units. The optical transition at 1.70 eV, determined from the diffuse reflectance is attributed to the inter band d d transi tion of Cu þ ion. The oxide exhibits semiconducting properties with an activation energy of 0.21 eV. The photo electrochemical measurement shows p type conduction due to O 2 insertion in the two dimen sional lattice. The flat band potential (þ0.12 V SCE), indicates a cationic character of both valence and conduction bands deriving from Cu þ : 3d orbital.

Facile Solvothermal Preparation of Mn2CuO4 Microspheres: Excellent Electrocatalyst for Real-Time Detection of H2O2 Released from Live Cells

“…Further, from the Mn 2p spectrum in Figure 2e, the binding energies of 643 and 654.5 eV have been ascribed to Mn 2p 3/2 and Mn 2p 1/2 , correspondingly. 42 The calculated spin-energy separation of 11.5 coincides with the literature. 43 It can be further divided into four peaks.…”

“…Figure c presents the survey scan of MCO, authorizing the presence of Mn, Cu, and O. Further, from the Mn 2p spectrum in Figure e, the binding energies of 643 and 654.5 eV have been ascribed to Mn 2p 3/2 and Mn 2p 1/2 , correspondingly . The calculated spin-energy separation of 11.5 coincides with the literature .…”

“…41,42 In addition, the weak band at 1620 cm −1 and strong vibration at 3430 cm −1 are ascribed to the bending and stretching vibration modes of absorbed water, respectively. 42 Consequently, FT-IR results further confirm the formation of Mn 2 CuO 4 .…”

“…The vibration bands at 437 and 520 cm –1 were assigned to the stretching vibrations of Mn–O . The bands at 556 and 618 cm –1 correspond to the stretching vibrations of Cu–O, whereas a couple of weak intense peaks at 1103 and 658 cm –1 are ascribed to Mn 3+ stretching vibration in the octahedral site and linear units of CuO 2 3– , correspondingly. , In addition, the weak band at 1620 cm –1 and strong vibration at 3430 cm –1 are ascribed to the bending and stretching vibration modes of absorbed water, respectively . Consequently, FT-IR results further confirm the formation of Mn 2 CuO 4 .…”

Relationship between morphological and physical properties in nanostructured CuMnO2

“…In the last few decades, there has been a renewed interest in the research on the CuMnO 2 material due to its an exceedingly rich spectrum of potential applications. As a p-type semiconductor [5][6][7], electrode material [8], CuMnO 2 has also been examined regarding photocatalytic activities for hydrogen production or hydrogen storage [9][10][11], oxygen storage [12,13], energy storage [14,15] as well as in the context of multiferroic peculiarities [16]. Remarkably, by the use of a hydrothermal method, nanoparticles with diameters of 50 -100 nm [6], or nanowires [15], can be obtained.…”