Issue 46, 2018

Insights into in situ one-step synthesis of carbon-supported nano-particulate gold-based catalysts for efficient electrocatalytic CO2 reduction

Abstract

Gold materials are typical catalysts for electroreduction of CO2 into CO. However, a conventional two-step method involving pre-forming gold nanoparticles and their subsequent deposition on carbon is inconvenient and uneconomical. Herein, carbon supported gold/gold sulfide nanoparticles (ca. 4.2 nm) and gold/gold(III) compound nanoparticles (ca. 4.1 nm) were synthesized via an in situ one-step procedure using sodium sulfide (SS) and urea (UR) as precipitating agents, respectively. Preliminary electroreduction at −0.78 V versus the reversible hydrogen electrode (RHE) in CO2-saturated KHCO3 could reduce and reconstruct the two freshly prepared catalysts, i.e., Au–SS/C and Au–UR/C, into carbon-supported metallic gold nanoparticles with a somewhat larger size and result in a substantial removal of residual CTAC ligands. Detectable amounts of mono- and poly-sulfides remained on the Au surface of the reduced Au–SS/C. Studies on electrocatalytic CO2 reduction revealed that the electrochemically reduced forms of Au–SS/C and Au–UR/C deliver 1.7-fold and 2-fold enhanced maximum CO current densities at around −0.96 V versus RHE compared with polycrystalline Au foil, respectively. Besides, they exhibit CO faradaic efficiencies as high as 91.8% and 94.2%, respectively, and show good long-term stability. Argon-annealing of the two freshly prepared catalysts could also transform the gold sulfide and gold(III) compound into metallic gold, but decreased the number and/or accessibility of active sites, being proved as a counterproductive strategy for electroreduction of CO2 to CO.

Graphical abstract: Insights into in situ one-step synthesis of carbon-supported nano-particulate gold-based catalysts for efficient electrocatalytic CO2 reduction

Supplementary files

Article information

Article type
Paper
Submitted
07 Sep 2018
Accepted
25 Oct 2018
First published
26 Oct 2018

J. Mater. Chem. A, 2018,6, 23610-23620

Insights into in situ one-step synthesis of carbon-supported nano-particulate gold-based catalysts for efficient electrocatalytic CO2 reduction

Y. Zhang, L. Hu and W. Han, J. Mater. Chem. A, 2018, 6, 23610 DOI: 10.1039/C8TA08698B

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