Method for Electrocatalytic Reduction using Au Nanoparticles Tuned or Optimized for Reduction of CO2 to CO

Patent metadata

Field	Value
Publication number	US-2016230295-A1
Application number	US-201615099691-A
Country	US
Kind code	A1
Filing date	Apr 15, 2016
Priority date	Oct 16, 2013
Publication date	Aug 11, 2016
Grant date	—

Abstract

Selective electrocatalytic reduction of carbon dioxide (CO 2 ) to carbon monoxide (CO) on gold (Au) nanoparticles (NPs) in 0.5 M KHCO 3 at 25° C. Among monodisperse 4-, 6-, 8-, and 10-nm NPs tested, the 8 nm Au NPs show the maximum Faradaic efficiency (FE), up to 90% at −0.67 V vs. reversible hydrogen electrode. Density functional theory (DFT) calculations suggest that edge sites dominate over corner sites on the Au NP surface facilitating stabilization of the reduction intermediates, such as COOH1*, and the formation of CO. This mechanism is further supported by the fact that Au NPs embedded in a matrix of butyl-3methylimidazolium hexafluorophosphate for more efficient COOH* stabilization exhibit even higher reaction activity (3 A/g mass activity) and selectivity (97% FE) at −0.52 V (vs. RHE). Use of monodisperse Au NPs to optimize the available reaction intermediate binding sites thus allows efficient and selective electrocatalytic reduction of CO 2 to CO.

First claim

1 . A process for electrocatalytic reduction of CO 2 to CO wherein the reduction is Catalyzed by gold nanoparticles on a conductive support, and the nanoparticles are sized to present a crystalline structure that achieves a stable and efficient reduction.

2 . The process of claim 1 , wherein the nanoparticles are tuned to present a crystalline structure of the nanoparticles, having lower amount of hydrogen-evolving crystal corner sites and greater amount of CO-converting edge sites, thereby forming a clean CO 2 conversion medium with low formation of by-product species.

3 . The process of claim 1 , wherein the conductive support is Ketjen carbon.

4 . The process of claim 1 , wherein the gold nanoparticles are formed with a diameter under 10 nm to effectively tune the catalytic activity of the particles.

5 . The process of claim 4 , wherein the gold nanoparticles are formed with a diameterof approximately 8 nm.

6 . The process of claim 1 , carried out in alkaline ionic liquid solution.

7 . A catalyst, comprising gold nanoparticles of approximately 8 nm diameter for use in electrocatalytic reduction of carbon dioxide to carbon monoxide.

8 . The catalyst of claim 7 , wherein the 8 nm Au NPs are polycrystalline with an approximately 4 nm crystallite diameter to provide a near-optimum number of edge sites that are particularly active for CO 2 reduction into CO while providing a low number of corner sites active for the HER.

9 . A catalyst, comprising gold nanoparticles of a cuboctahedral crystalline configuration and microcrystal size to present CO-converting edge sites with relatively fewer hydrogen-evolving corner sites, thereby being tuned to form a clean CO 2 conversion medium with low formation of by-product.

10 . The catalyst of claim 8 , wherein the nanoparticles have a microcrystalline dimension less than nanoparticle diameter that tunes the catalyst to resist poisoning by reduction by-products.

Assignees

• Univ Brown

Inventors

• Sun Shouheng
• Peterson Andrew
• Zhu Wenlei
• Michalsky Ronald

Classifications

• C25B11/0473 Primary

  Chemistry & Metallurgy · mapped topic

• C25B11/0415

  Chemistry & Metallurgy · mapped topic

• C30B29/02

  Elements · CPC title

• C25B1/00

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C25B11/0405

  Chemistry & Metallurgy · mapped topic