Linghui Kong , Min Wang , Yongxiao Tuo , Shanshan Zhou , Jinxiu Wang , Guangbo Liu , Xuejing Cui , Jiali Wang , Luhua Jiang
{"title":"A cascade of in situ conversion of bicarbonate to CO2 and CO2 electroreduction in a flow cell with a Ni-N-S catalyst","authors":"Linghui Kong , Min Wang , Yongxiao Tuo , Shanshan Zhou , Jinxiu Wang , Guangbo Liu , Xuejing Cui , Jiali Wang , Luhua Jiang","doi":"10.1016/j.jechem.2023.09.024","DOIUrl":null,"url":null,"abstract":"<div><p>Combination of CO<sub>2</sub> capture using inorganic alkali with subsequently electrochemical conversion of the resultant <span><math><msubsup><mtext>HCO</mtext><mrow><mtext>3</mtext></mrow><mtext>-</mtext></msubsup></math></span> to high-value chemicals is a promising route of low cost and high efficiency. The electrochemical reduction of <span><math><msubsup><mtext>HCO</mtext><mrow><mtext>3</mtext></mrow><mtext>-</mtext></msubsup></math></span> is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface. Herein, we adopt a comprehensive strategy to tackle this challenge, i.e., cascade of in situ chemical conversion of <span><math><msubsup><mtext>HCO</mtext><mrow><mtext>3</mtext></mrow><mtext>-</mtext></msubsup></math></span> to CO<sub>2</sub> and CO<sub>2</sub> electrochemical reduction in a flow cell. With a tailored Ni-N-S single atom catalyst (SACs), where sulfur (S) atoms located in the second shell of Ni center, the CO<sub>2</sub> electroreduction (CO<sub>2</sub>ER) to CO is boosted. The experimental results and density functional theory (DFT) calculations reveal that the introduction of S increases the <em>p</em> electron density of N atoms near Ni atom, thereby stabilizing *H over N and boosting the first proton coupled electron transfer process of CO<sub>2</sub>ER, i.e., *+e<sup>–</sup>+*H+*CO<sub>2</sub>→*COOH. As a result, the obtained catalyst exhibits a high faradaic efficiency (FE<sub>CO</sub> ∼ 98%) and a low overpotential of 425 mV for CO production as well as a superior turnover frequency (TOF) of 47397 h<sup>−1</sup>, outcompeting most of the reported Ni SACs. More importantly, an extremely high FE<sub>CO</sub> of 90% is achieved at 50 mA cm<sup>−2</sup> in the designed membrane electrode assembly (MEA) cascade electrolyzer fed with liquid bicarbonate. This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO<sub>2</sub>ER, but also provides an alternative and feasible strategy to realize the electrochemical conversion of <span><math><msubsup><mtext>HCO</mtext><mrow><mtext>3</mtext></mrow><mtext>-</mtext></msubsup></math></span> to high-value chemicals.</p></div>","PeriodicalId":67498,"journal":{"name":"能源化学","volume":"88 ","pages":"Pages 183-193"},"PeriodicalIF":14.0000,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"能源化学","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2095495623005399","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
Combination of CO2 capture using inorganic alkali with subsequently electrochemical conversion of the resultant to high-value chemicals is a promising route of low cost and high efficiency. The electrochemical reduction of is challenging due to the inaccessible of negatively charged molecular groups to the electrode surface. Herein, we adopt a comprehensive strategy to tackle this challenge, i.e., cascade of in situ chemical conversion of to CO2 and CO2 electrochemical reduction in a flow cell. With a tailored Ni-N-S single atom catalyst (SACs), where sulfur (S) atoms located in the second shell of Ni center, the CO2 electroreduction (CO2ER) to CO is boosted. The experimental results and density functional theory (DFT) calculations reveal that the introduction of S increases the p electron density of N atoms near Ni atom, thereby stabilizing *H over N and boosting the first proton coupled electron transfer process of CO2ER, i.e., *+e–+*H+*CO2→*COOH. As a result, the obtained catalyst exhibits a high faradaic efficiency (FECO ∼ 98%) and a low overpotential of 425 mV for CO production as well as a superior turnover frequency (TOF) of 47397 h−1, outcompeting most of the reported Ni SACs. More importantly, an extremely high FECO of 90% is achieved at 50 mA cm−2 in the designed membrane electrode assembly (MEA) cascade electrolyzer fed with liquid bicarbonate. This work not only highlights the significant role of the second coordination on the first coordination shell of the central metal for CO2ER, but also provides an alternative and feasible strategy to realize the electrochemical conversion of to high-value chemicals.