Selective Catalytic Electroreduction of CO2 at Silicon Nanowires (SiNWs) Photocathodes Using Non-Noble Metal-Based Manganese Carbonyl Bipyridyl Molecular Catalysts in Solution and Grafted onto SiNWs - Université de Rennes Accéder directement au contenu
Article Dans Une Revue ACS Catalysis Année : 2015

Selective Catalytic Electroreduction of CO2 at Silicon Nanowires (SiNWs) Photocathodes Using Non-Noble Metal-Based Manganese Carbonyl Bipyridyl Molecular Catalysts in Solution and Grafted onto SiNWs

Encarnacion Torralba-Penalver
Yun Luo
Jean-Daniel Compain
  • Fonction : Auteur
Sylvie Chardon-Noblat
Bruno Fabre

Résumé

The electrocatalytic redn. of CO2 to CO in hydroorg. medium has been investigated at illuminated (λ \textgreater 600 nm; 20 mW cm-2) hydrogen-terminated silicon nanowires (SiNWs-H) photocathodes using three Mn-based carbonyl bipyridyl complexes as homogeneous mol. catalysts ([Mn(L) (CO)3(CH3CN)](PF6) and [Mn(bpy) (CO)3Br] with L = bpy = 2,2'-bipyridine and dmbpy = 4,4'-dimethyl-2,2'-bipyridine). Systematic comparison of their cyclic voltammetry characteristics with those obtained at flat hydrogen-terminated silicon and traditional glassy carbon electrodes (GCE) enabled us to demonstrate the superior catalytic efficiency of SiNWs-H in terms of cathodic photocurrent densities and overpotentials. For example, the photocurrent densities measured at -1.0 V vs SCE for [Mn(bpy) (CO)3(CH3CN)](PF6) at SiNWs-H exceeded 1.0 mA cm-2 in CO2-satd. CH3CN + 5% vol./vol. H2O, whereas almost zero current was measured at this potential at GCE. Such characteristics have been supported by the energetic diagrams built for the different SiNWs\textbarMn-based catalyst interfaces. The fill factor FF and energy conversion efficiency η calcd. under catalytic conditions were higher for [Mn(bpy or dmbpy) (CO)3(CH3CN)](PF6) (FF = 0.35 and 0.34; η = 3.0 and 2.0%, resp.). Further preparative-scale electrolysis at SiNWs-H photocathode with Mn-based complex catalysts in electrolytic soln. evidenced the quant. conversion of CO2 to CO with a higher stability of the [Mn(dmbpy) (CO)3(CH3CN)](PF6) complex. Finally, in order to develop technol. viable electrocatalytic devices, the elaboration of SiNWs-H photoelectrodes modified with a Mn-based complex has been successfully achieved from an electropolymerizable catalyst, and it was shown that the electrocatalytic activity of the complex was retained after immobilization.

Domaines

Chimie

Dates et versions

hal-01208405 , version 1 (02-10-2015)

Identifiants

Citer

Encarnacion Torralba-Penalver, Yun Luo, Jean-Daniel Compain, Sylvie Chardon-Noblat, Bruno Fabre. Selective Catalytic Electroreduction of CO2 at Silicon Nanowires (SiNWs) Photocathodes Using Non-Noble Metal-Based Manganese Carbonyl Bipyridyl Molecular Catalysts in Solution and Grafted onto SiNWs. ACS Catalysis, 2015, 5 (10), pp.6138-6147. ⟨10.1021/acscatal.5b01546⟩. ⟨hal-01208405⟩
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