Exploration of octahedrally shaped MnCo₂O₄ catalyst particles for visible light driven photocatalytic water splitting reaction

Abstract

MnCo2O4 catalyst with an octahedral geometry and 2.11 eV band gap was developed for visible light driven photocatalytic water splitting considering the crucial roles of Co(iii)OH, and cobalt(ii) oxide and Mn3+ in Co3O4 and Mn2O3 photocatalysts for water splitting.

On the Origin of the Improvement of Electrodeposited MnOx Films in Water Oxidation Catalysis Induced by Heat Treatment

“…[15] MnO only plays am arginal role with about 3% contribution,a nd Mn 2 O 3 and MnO 2 make no measurable contribution. [9,10,16,20,30] The absence of the Mn 2 O 3 and MnO 2 phases also indicates that the Mn oxidation state is not the only factor determining the MnO x XA spectra, otherwise the XA spectra of the reference manganese oxides with pure oxidation states, that is, MnO (2 +), Mn 2 O 3 (3 +)a nd MnO 2 (4 +), would be the only sufficient and necessary basis functions for the linear expansion of the MnO x XA spectra. The shift only occurs when the MnO x films are heated up to 90 8C, consistent with the two categories discussed previously for Figure 1.…”

“…Surprisingly,n oM n 2 O 3 phase was discovered in the MnO x material, even thoughi tc ontains only Mn 3 + centresw hich are often believed to be the most effective ingredient in water oxidation catalysis. [9,10,16,20,30] The absence of the Mn 2 O 3 and MnO 2 phases also indicates that the Mn oxidation state is not the only factor determining the MnO x XA spectra, otherwise the XA spectra of the reference manganese oxides with pure oxidation states, that is, The equal percentage of the birnessite and Mn 3 O 4 phases for the 90 and 120 8Cs pectra in Figure 3i ndicates that the differenceo ft he catalytic performances after theset wo temperature treatments does not originate from the Mn-related species in the MnO x structure. The argument of the loss of the water Table S1 in the SupportingI nformation andplottedwith the error bars created by the fitting algorithm.…”

“…[10,14,18] Previous studies suggest that the birnessite-like MnO x and Mn 2 O 3 exhibit higherc atalytic performance than Mn 3 O 4 and MnO 2 .T he series of ad eclining performance follows an order,( birnessite, Mn 2 O 3 ) > Mn 3 O 4 > (MnO, MnO 2 ), that basically mirrorst he decrease of the Mn 3 + concentration in these manganese oxides. [9,10,16,20] This is supported by investigations showingt hat MnO x films electrodeposited from aqueous electrolytes, which are poorly active at pH 7, show much improved activity in basic solution (pH > 9), ar egime under which Mn 3 + is stabilized. [10] Indeed, suppression of the disproportionation reaction, andc onsequent stabilization of Mn 3 + ,h as been linked to as ignificant increase in catalytic activity.…”

Electrospinning construction of Bi2WO6/RGO composite nanofibers with significantly enhanced photocatalytic water splitting activity

“…Semiconductor photocatalyst has attracted much attention owing to its great potential in energy 30 production and environmental purification [3][4][5] . So far, various 35 semiconductor photocatalysts have been investigated, such as BiVO 4 [6] , Bi 2 WO 6 [7] , MnCo 2 O 4 [8] , C 3 N 4 [9] , TiO 2 [10] , Bi 2 MoO 6 [11] , ZnO [12] . Moreover, the position of the conduction band (CB) potential should be more negative than the reduction potential (H + /H 2 ).…”

Activation of peroxymonosulfate with magnetic and recyclable Fe3 O4 @C/MnCo2 O4 nanocomposites for the decolorization of Acid Orange II

“…The problem of metal leaching can also be reduced by the strong metal–metal bonding interactions in the spinel structures . On the other hand, besides the high performance for energy storage and conversion, spinel manganese cobaltite MnCo 2 O 4 also displays excellent catalytic activity for the reactions of water oxidation and oxygen reduction, photocatalytic water splitting, and photocatalytic reduction of CO 2 . However, in contrast to the larger number of reports on the spinel‐type ferrites MFe 2 O 4 (M = Mn, Fe, Cu, Co, Ni) in activating PMS for the oxidation of organic pollutants, reports on the catalysis of spinel manganese cobaltites for PMS activation are very limited.…”