不同浸渍时间对CuO/Cu@BC电极催化CO2还原性能的影响

Effect of different soaking time on catalytic performance of CuO/Cu@BC electrode for CO reduction

将具有3D网状结构的细菌纤维素(BC)膜作为催化剂载体,通过原位化学还原法制备了负载Cu和Cu O纳米复合材料的催化剂电极(Cu O/Cu@BC),并通过改变BC膜的浸渍时间实现电极结构调控以探索最佳条件。结果表明,具有3D球形结构的Cu O/Cu24h@BC电极对CO2还原表现出较好的电子传输性能和更高的电流密度。Cu O/Cu24h@BC电极的电化学比表面积最大,达12 mF/cm2。Cu O/Cu24h@BC电极可将CO2电催化转化为CO,且产生CO的法拉第效率为52%。

As an environmentally-friendly and costeffective biological 3 D carbon nanomaterial,bacterial cellulose(BC)has been gradually used in flexible electronics.However,the application of BC in electrochemical CO2 reduction(ECR-CO2)reactions is rare.Herein,to promote its applications in ECR-CO2,BC with a 3 D network structure was used as a catalyst carrier,and a catalyst electrode(CuO/Cu@BC)supporting Cu and CuO nanocomposites was prepared by in situ chemical reduction.To investigate optimal conditions,the soaking time of the BC membrane was changed to achieve structure regulation.The results revealed that at a soaking time of 24 h,the CuO/Cu24 h@BC electrode exhibited a high electroactive area(12 mF/cm2),providing a considerable increase in the number of active sites for CO2 absorption;this result was verified by investigation of the electrocatalytic activity and performance.The electrochemical impedance test revealed that the activation resistor of the electrode was small and that the activation energy was high,thereby improving the electron conductivity by building an efficient transfer highway for Cu and CuO.Scanning electron microscopy analysis of the morphology of the CuO/Cu@BC electrode revealed a uniform coverage in addition to the even decoration of nanoparticles(50~70 nm)on the top,facilitating the penetration of the electrolyte.On the other hand,the seaweed structure of the CuO/Cu8 h@BC electrode and the adverse combination of the nanoparticles of the CuO/Cu16 h@BC electrode were disadvantageous to the transformation of CO2.In terms of the product analysis by ECR-CO2,the CuO/Cu24 h@BC electrode exhibited outstanding selectivity for CO with a faradaic efficiency of 52%at a potential of-0.6 V vs.RHE in a 0.5 mol/L KHCO3 electrolyte.All the above results demonstrated that BC was superior as an efficient electrode substrate to support electrocatalysts for CO2 reduction and that the CuO/Cu24 h@BC electrode exhibited good performance for the reduction of CO2 to CO.