Polyethylenimine‐assisted Synthesis of Au Nanoparticles for Efficient Syngas Production

Abstract

The ability to capture, store, and use CO2 is important for remediating greenhouse‐gas emissions and combatting global warming. Herein, Au nanoparticles (Au‐NPs) are synthesized for effective electrochemical CO2 reduction and syngas production, using polyethylenimine (PEI) as a ligand molecule. The PEI‐assisted synthesis provides uniformly sized 3‐nm Au NPs, whereas larger irregularly shaped NPs are formed in the absence of PEI in the synthesis solution. The Au‐NPs synthesized with PEI (PEI−Au/C, average PEI Mw=2000) exhibit improved CO2 reduction activities compared to Au‐NPs formed in the absence of PEI (bare Au NPs/C). PEI−Au/C displays a 34 % higher activity toward CO2 reduction than bare Au NPs/C; for example, PEI−Au/C exhibits a CO partial current density (jCO) of 28.6 mA cm−2 at −1.13 VRHE, while the value for bare Au NPs/C is 21.7 mA cm−2; the enhanced jCO is mainly due to the larger surface area of PEI−Au/C. Furthermore, the PEI−Au/C electrode exhibits stable performance over 64 h, with an hourly current degradation rate of 0.25 %. The developed PEI−Au/C is employed in a CO2‐reduction device coupled with an IrO2 water‐oxidation catalyst and a proton‐conducting perfluorinated membrane to form a PEI−Au/C|Nafion|IrO2 membrane‐electrode assembly. The device using PEI−Au/C as the CO2‐reduction catalyst exhibits a jCO of 4.47 mA/cm2 at 2.0 Vcell. Importantly, the resulted PEI−Au/C is appropriate for efficient syngas production with a CO ratio of around 30–50 %.

Hydrogen Evolution and Oxygen Reduction Reactions in Acidic Media Catalyzed by Pd4S Decorated N/S Doped Carbon Derived from Pd Coordination Polymer

“…In this case, Pd is much more abundant than platinum, which might have a considerable benefit as electrocatalytic material candidates encompassing a wide variety of applications, such as energy conversion, [ 8 ] specific organic reactions, [ 9 ] and electrochemical sensors. [ 10,11 ] Thus, it is necessary to explore a new kind of non or less noble metal catalysts with the superior catalytic performance to or comparable with Pt/C catalysts.…”

Combined Effect of Catholyte Gap and Cell Voltage on Syngas Ratio in Continuous CO2/H2O Co-electrolysis

“…PEI-Au/C was selected as the e-CORR catalyst [32,33]. As reported previously, Au NPs synthesized in the presence of PEI have a smaller size of 3 nm for enhanced CO 2 reduction activity [32]. The catalyst NPs supported on a highly conductive carbon presented a uniform size distribution (size of approximately 100 nm), as shown in the TEM image (Fig.…”

“…PEI-Au/C was selected as the e-CORR catalyst [32,33]. As reported previously, Au NPs synthesized in the presence of PEI have a smaller size of 3 nm for enhanced CO 2 reduction activity [32].…”

“…Au nanoparticles (NPs) were synthesized in the presence of polyethylenimine (PEI-Au/C) as an e-CORR catalyst [32]. Briefly, the PEI-Au/C powder was synthesized by the chemical reduction of HAu-Cl 4 •3H 2 O (Sigma-Aldrich, St. Louis, MO, USA, 99.9%) using NaBH 4 (Sigma-Aldrich, 99%,) in the presence of PEI (Sigma-Aldrich, 50 wt.% in water, Mw~2000) in an ethanol solution.…”

Insights into Highly-Efficient CO2 Electroreduction to CO on Supported Gold Nanoparticles in an Alkaline Gas-Phase Electrolyzer

“…The application of Au catalyst in the CO 2 electrolyzer has made some progress, 20 but there are still some problems such as high energy consumption 21 and insufficient product selectivity. 22 In our previous work, the gold loading amount on N-doped carbon (CN) was regulated. 14 In this work, the influence of nitrogen doping was further explored by adjusting the C/N mass ratio and quenching the nitrogen site.…”