电化学还原二氧化碳合成碳材料电催化还原氧气合成过氧化氢

Electrochemical Reduction of Carbon Dioxide to Carbon Materials for Two-Electron Oxygen Reduction Reaction

研究了3种不同阳极(铜丝,镀锌铁丝和镍丝)材料对在熔盐中电化学还原CO_(2)制备的碳材料结构和形貌的影响,并探究了制备的3种碳材料,中空四面体碳(HQC,Cu作为阳极时的还原产物)、碳纳米片(CNS,Fe作为阳极时的还原产物)和海绵状多孔碳(SPC,Ni作为阳极时的还原产物),对2电子氧还原反应(2e;ORR)的电催化性能。研究表明,使用镀锌铁丝作为阳极材料制备的CNS由大量的碳纳米片构成,且该纳米片上具有丰富的孔洞结构以及较大的I_(D)/I_(C)(Raman光谱中D峰与G峰的强度之比,其比值反映材料的缺陷程度)值(0.996)。与HQC和SPC相比,CNS表现出最高的2e;ORR电催化活性和H_(2)O_(2)选择性(接近90%)。CNS的高活性和高选择性归因于其高的I_(D)/I_(C)值和高C—O/C=O比值,说明结构缺陷和C—O/C=O官能团对CNS催化性能至关重要。此外,CNS还具有非常优异的电催化稳定性,在长达14 h的恒电压电化学催化测试后,环电流几乎无衰减。这种以CO_(2)为碳源合成可用于电催化合成过氧化氢(H_(2)O_(2))的碳材料的方法,不仅可以作为缓解温室效应的潜在选项,也为CO_(2)衍生碳的实际应用提供了新的思路。

In this paper,the effects of three different anodic materials(copper wire,galvanized steel and nickel wire)on the structure and morphology of carbon materials prepared by electrochemical reduction of CO_(2)in molten salt were studied.Three carbon structures,e.g.,hollow quadrilateral carbon(HQC,the product with Cu as an anode),carbon nanosheet(CNS,the product with galvanized steel as an anode)and sponge porous carbon(SPC,the product with Ni as an anode),were prepared,and their electrocatalytic properties towards the two-electron oxygen reduction reaction(2e;ORR)were explored.The results show that the CNS prepared by using galvanized steel as the anode material is composed of a large number of carbon nanosheets,in which there are abundant pore structure defects.Compared with HQC and SPC,CNS shows the highest 2e;ORR electrocatalytic activity and H_(2)O_(2)selectivity(close to 90%).The high activity and selectivity of CNS are attributed to its high I_(D)/I_(C)(I_(D)/I_(C)is the ratio of the intensity of D peak and G peak in Raman spectrum,and its ratio reflects the defective degree of the material)value and high C—O/C=O ratio,indicating that structural defects and C—O/C=O functional groups are crucial to the catalytic performance of CNS.In addition,CNS exhibits excellent electrocatalytic stability,and the ring current almost does not decay after 14 hours potentiostatic test.The use of CO_(2)as the carbon source to synthesize electrocatalytic carbon materials not only can be used as a potential option to mitigate the greenhouse effect,but also provide a new idea for the practical application of CO_(2)derived carbons.