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Functionalization of AU eletrocatalysts by imidazole dithiocarbamate derivatives: exploring the molecular junction as strategy for electroreduction of carbon dioxide

Grant number: 18/10415-7
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): December 01, 2018
Effective date (End): November 30, 2020
Field of knowledge:Physical Sciences and Mathematics - Chemistry
Principal Investigator:Fabio Henrique Barros de Lima
Grantee:Maykon Lima Souza
Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
Associated research grant:13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion, AP.TEM

Abstract

The electrocatalytic reduction of carbon dioxide (CO2) is a key theme on the global research concerning stock and energy conversion. Due the multidisciplinary of the problem, these investigations apply concepts from different sciences. For instance, the functionalization of metallic surfaces by organic molecules is considered an elegant and efficient strategy to modulate the catalytic activity of electrodes. In this project is proposed the exploration of the CO2 electroreduction control in aqueous media by modify Au electrodes surfaces with dithiocarbamates (DTC) containing imidazole and aliphatic carbon chains. The strategy is based on: 1) Solid evidences that DTC (R2N-CS2-) form stronger interaction in metal surface than thiols (RSH), thermally more stable, more resistant to acid and basic pHs, and generate stronger electronic coupling; 2) Pyridine (pyr) anchored on Au electrode was reported to increase the selectivity of the electroreduction of CO2 to HCOO- owing the pyr/pyrH+ species (pKa ~ 5.2); 3) The imidazolium cation (ImNH+) in polymers, promotes the stabilization of the anion radical of carbon dioxide (CO2*-) and favor its electroreduction to CO; 4) The use of imidazole-DTC having aliphatic carbon chains (-CnH2n+1) with different lengths, provides a simple way to modulate the hydrophobic feature of the molecular junction on the metallic surface. Such strategy might be used to control the access of H+ ions to the surface and consequentially the generation of H2 and other hydrogenated products, like HCOO-. The Au electrocatalysts containing DTCs derivatives of the methylamine Imidazole-CnH2n+1 (n = 0, 5 e 8) will be synthesized in the laboratory and faradic efficiencies will be calculated by means of the determination of the reaction products in on-line and in-line experiments, via mass spectrometry and gas chromatography, respectively.