【摘要】 电催化CO₂还原技术有望同时缓解化石燃料濒临枯竭及大气中CO₂浓度不断攀升等问题.然而,对于高附加值的电催化CO₂还原多碳产物的选择性提升,仍然面临巨大挑战.密度泛函理论（DFT）计算表明,Cu₂O-Cu界面上Cu⁺和Cu⁰的协同耦合效应使其表面上^*COCO中间体的生成能降低,同时H₂O的解离自由能也降低,从而有利于电催化CO₂还原高选择性生成多碳产物特别是C₂H₄.受DFT计算结果的启发,本文设计了一种氧化物衍生铜电极的活化策略,构建Cu₂O-Cu界面,以Cu⁺和Cu⁰协同促进电催化CO₂还原高效高选择性生成C₂₊产物.其中,Cu₂O立方体被用作初始催化剂,经方波电位处理后,在Cu₂O-Cu界面上形成了具有Cu⁺和Cu⁰协同作用的S W-Cu₂O/Cu立方体.在H型电解池中,SW-Cu₂0/Cu电催化CO₂还原生成C₂H₄和C₂₊产物的法拉第效率分别为60%和75%,约为前驱体Cu₂O立方体的1.5倍,证明Cu^G和Cu⁺在Cu₂O-Cu界面上的协同作用的确可提高电催化CO₂还原过程中特定高附加值多碳产物的选择性.更多还原

【Abstract】 The electrocatalytic CO₂ reduction technology is expected to simultaneously alleviate increasing CO₂ emissions and the depletion of fossil resources.However,it is still a big challenge to improve the selectivity toward valuable multicarbon products in electrocatalytic CO₂ reduction reaction.In this study,the synergistic role of Cu⁺and Cu⁰ species in Cu₂OCu interfaces is unravelled through density functional theory（DFT）calculations,in which the electrode surface exhibits low free energy of ^*COCO intermediate formation and H₂O dissociation,which are beneficial to the high selectivity towards multi-carbon products,especially C₂H₄.Guided by these DFT results,an oxide-derived copper electrode activation strategy that builds the synergistic Cu⁺and Cu⁰ on Cu₂O-Cu interfaces is designed to boost the selectivity toward multi-carbon products.Interestingly,Cu₂O cubes chosen as the pristine catalyst are activated via a square-wave（SW）potential treatment to form SW-Cu₂O cubes that bear Cu⁺ and Cu⁰ species.The asprepared SW-Cu₂O cubes exhibit superior Faradaic efficiencies for C₂H₄（60%）and C₂₊products（75%）in an H-type cell,which are about 1.5 times that of the Cu₂O cubes.This study demonstrates the synergistic Cu⁰ and Cu⁺on Cu₂O-Cu interfaces for improving the selectivity of a specific valuable multi-carbon product in electrocatalytic CO₂ conversion.更多还原