Synergistic Chemisorbing and Electronic Effects for Efficient CO₂ Reduction Using Cysteamine-Functionalized Gold Nanoparticles

Abstract

Inspired by the architectural feature of the natural enzyme of carbon monoxide dehydrogenase, cysteamine-capped Au nanoparticles (CA−Au NPs) are investigated with remarkable mass activity for CO 2 reduction. CA− Au NPs exhibit exclusive CO selectivity, low onset overpotential, and a 110-fold enhancement in mass activity compared with ligand-free Au NPs. Electronic structure and in situ spectroscopy analyses indicate that increased activity is due to the electronic effect derived from thiolate anchoring on the surface and chemisorbing CO 2 and intermediates by terminal -NH 2 functional groups. Our study provides the basis for fabricating effective catalysts for CO 2 reduction.

Transition metal-based catalysts for the electrochemical CO2reduction: from atoms and molecules to nanostructured materials

“…419 An analogous boosting effect due to cysteamine capping agents was also recently reported for Au NPs, showing an exclusive CO selectivity at low overpotential and a 110-fold enhanced mass activity in comparison with the naked Au NPs. 420 XAS spectroscopy confirmed the effect of the Au-S interactions on altering the electronic structure of the gold surface and EXAFS analysis confirmed a lower Au-Au coordination number for cysteamine-Au NPs in comparison with the ligandfree Au NPs. Furthermore, the replacement of cysteamine with 1-propanethiol as a capping agent (terminal CH 3 group) resulted in a significant drop of the CO 2 RR catalytic activity, thereby probing the critical role played by the NH 2 group of the former.…”

“…Furthermore, the replacement of cysteamine with 1-propanethiol as a capping agent (terminal CH 3 group) resulted in a significant drop of the CO 2 RR catalytic activity, thereby probing the critical role played by the NH 2 group of the former. 420 Notably, outer coordination sphere effect on CO 2 RR activity and selectivity has been also observed on polycrystalline Au foil functionalized with thio-tethered ligands. 421 Depending on the pK a of the terminal group of the thiolate ligand, the activity and faradaic efficiency toward CO, H 2 and HCOO À could be tuned.…”

“…The use of cysteamine as anchoring agent has revealed to be beneficial for the CO 2 RR performances of Au NPs and Ag NPs. 388,419,420 For an optimal particle size of 5 nm, Ag NPs on carbon decorated with cysteamine molecules showed a considerably lower overpotential and a 4-fold enhanced CO faradaic efficiency at À0.75 V vs. RHE compared to a polycrystalline Ag foil. 388 While Tafel slope analysis suggested the formation of the *CO 2 À adduct to be rate-limiting, DFT calculations highlighted an electronic effect on the Ag surface induced by the Ag-S interaction, which is reminiscent of the throughstructure substituent effects observed in molecular catalysts (see Section 3).…”

Electrochemical Reduction of Carbon Dioxide on Au Nanoparticles: An in Situ FTIR Study

“…As a model electrocatalyst, Au has been broadly and intensively studied, where CO has been reported as the main product from the CO 2 reduction process . The mechanisms of CO 2 reduction on Au electrode surfaces are primarily based on hypotheses and theoretical calculations/modeling .…”

Highly Selective Electrocatalytic Reduction of CO2 into Methane on Cu–Bi Nanoalloys

“…The electrochemical reduction of CO 2 into value-added products provides an attractive strategy for reducing atmospheric CO 2 concentrations. − Intensive studies focusing on metal-based electrocatalysts for the CO 2 reduction reaction (CO 2 RR) have been conducted to distinguish candidates that are capable of reducing CO 2 into value-added chemicals, such as CO, , HCOOH, , CH 4 , , C 2 H 4 , , and C 2 H 5 OH . Cu is the only pure metal catalyst that is known to electrochemically convert CO 2 into appreciable amounts of hydrocarbons, such as CH 4 and C 2 H 4 .…”