化石燃料的燃烧导致大气中二氧化碳(CO2)的浓度迅速上升,并引发了严重的能源、环境危机.由可再生电力驱动的电催化CO2还原为增值化学品和燃料是解决当前化石燃料枯竭的一种有效方法.采用"一锅法"制备了磷(P)修饰的高分散性"钴-氮-碳"(Co-N-C/P)催化剂,通过扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)和X射线光电子能谱(XPS)等手段对催化剂的形貌、元素分布、缺陷程度、表面元素价态及配位结构进行了表征,并考察了其在H型电解槽中电催化CO2还原为CO的性能.测试结果表明,所制备的Co-N-C/P催化剂在-0.9 V vs.RHE的外加电位下具有97.0％的CO法拉第效率(FECO),电流密度为4.58 mA/cm2,并可以进行26 h的稳定性测试.与Co-N-C催化剂相比,P的掺杂更有利于Co原子在碳黑基底上的良好分散,相应的FECO提高了约38.9％,说明P的掺杂有效提高了 Co-N-C催化剂的电催化CO2还原为CO的性能.
Study on phosphorous-doped cobalt-nitrogen-carbon catalysts for electrocatalytic reduction of carbon dioxide
The burning of fossil fuels has led to a rapid increase in the concentration of carbon dioxide(CO2)in the atmosphere,resulting in a serious energy and environmental crisis.Electrocatalytic re-duction of CO2 to value-added chemicals and fuels,driven by renewable electricity,is an effective method for addressing the current depletion of fossil fuels.In this paper,a phosphorus-modified highly dispersible cobalt-nitrogen-carbon(Co-N-C)catalyst was prepared using a"one-pot"method.The catalyst's morphology,element distribution,defect degree,surface element valence and coordination structure were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),Raman spectroscopy,and X-ray photoelectron spectroscopy(XPS).The performance of the catalyst in the electrocatalytic reduction of CO2 to CO in an H-type cell was investigated.The results showed that the prepared Co-N-C/P catalyst exhibited a 97.0％CO Faraday Efficiency(FECO)at an applied po-tential of-0.9 V vs.RHE,with a current density of 4.58 mA/cm2,and demonstrated stability over a 26-hour test.Compared with the Co-N-C catalysts,the P-dopant facilitated a good dispersion of Co atoms on the carbon black substrate,resulting in an approximately 38.9％increase in FECO.These findings demonstrated that the P-dopant significantly enhanced the performance of Co-N-C catalysts effectively for the electrocatalytic reduction of CO2 to CO.
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