Polymer‐Supported Liquid Layer Electrolyzer Enabled Electrochemical CO₂ Reduction to CO with High Energy Efficiency

Abstract

The electrochemical conversion of carbon dioxide (CO 2 ) to carbon monoxide (CO) is a favorable approach to reduce CO 2 emission while converting excess sustainable energy to important chemical feedstocks. At high current density (>100 mA cm −2 ), low energy efficiency (EE) and unaffordable cell cost limit the industrial application of conventional CO 2 electrolyzers. Thus, a crucial and urgent task is to design a new type of CO 2 electrolyzer that can work efficiently at high current density. Here we report a polymer‐supported liquid layer (PSL) electrolyzer using polypropylene non‐woven fabric as a separator between anode and cathode. Ag based cathode was fed with humid CO 2 and potassium hydroxide was fed to earth‐abundant NiFe‐based anode. In this configuration, the PSL provided high‐pH condition for the cathode reaction and reduced the cell resistance, achieving a high full cell EE over 66 % at 100 mA cm −2 .

Anode Catalysts in CO2 Electrolysis: Challenges and Untapped Opportunities

“…In almost half of the cases (47%), Ir was employed as the anode catalyst, 10 , 12 , 13 , 16 , 18 , 29 , 32 , 34 , 36 − 87 Another 30% and 14% account for Ni 7 − 10 , 17 , 36 , 39 , 41 − 44 , 88 − 117 and Pt, 32 , 114 , 118 − 133 respectively, while only 9% is related to other metals, metal alloys, or carbon 11 , 45 , 60 , 117 , 134 − 140 ( Figure 3 A). The dominance of Ir and Ni is rooted in the fact that these are the generally used catalysts in acidic and alkaline water electrolyzers, respectively.…”

“…The colors consistently indicate the different catalysts. Data points were gathered from refs − , − , , , , and − …”

Amorphous carbon coating enhances activity of high rate CO2electroreduction to CO

“…1 It targets the conversion of CO 2 to useful chemicals such as CO, formate, hydrocarbon, oxygenated compounds and so on. 2 CO is a particularly promising target to achieve a balanced carbon cycle: 3 with easy separation of products, 4 simple reaction path, 5 high selectivity and energy conversion efficiency. 6 Also, a mixture of CO and H 2 (syngas) 7 can synthesize different fuels and value-added chemicals via well-developed industrial technologies ( e.g.…”

Regulation of Electrocatalytic Activity by Local Microstructure: Focusing on the Catalytic Active Zone

“…[5] At the same time, CO 2 RR is also affected by the competitive hydrogen evolution reaction (HER) and the selectivity of conversion to multi-carbon products is low. [6] The kinetics processes of the above reactions are affected by many factors, such as electrocatalyst properties, [7] interface microenvironment, [8] mass transfer, [9] external field action, [10] etc., which seriously restrict the further improvement of the conversion efficiency of electric energy and chemical energy. Therefore, the design and synthesis of new electrocatalysts with high activity, high selectivity, and high stability have become the core of this field.…”

“…However, both the oxygen evolution reaction (OER) in water splitting and CO 2 reduction reaction (CO 2 RR) involve multi‐step electron transfer processes, which make the kinetics slow, making it necessary to provide extra energy to overcome the reaction barrier [5] . At the same time, CO 2 RR is also affected by the competitive hydrogen evolution reaction (HER) and the selectivity of conversion to multi‐carbon products is low [6] . The kinetics processes of the above reactions are affected by many factors, such as electrocatalyst properties, [7] interface microenvironment, [8] mass transfer, [9] external field action, [10] etc., which seriously restrict the further improvement of the conversion efficiency of electric energy and chemical energy.…”