The Performance Of Electrochemical CO₂ Reduction On Copper-Based Catalyst With Dual Sites

It is one of the most effective ways that using renewable energy such as solar energy electroreduce CO₂ to value-added chemicals to solve the current energy crisis.However,the electrochemical reaction of CO₂ has many problems such as complex reaction,many products with low selectivity,high overpotential,and its reaction is also accompanied by high thermodynamics and slow kinetics.In order to solve the problems above,it is particularly important to design a catalyst with high selectivity and high efficiency to catalyze the electrochemical CO₂ reduction（ECR）.In this paper,three new copper-based catalysts with dual-site were designed to carry out the ECR to produce C₂₊compounds.Firstly,a ZnO@Cu₂O core-shell nanocatalysts was synthesized by a combination of sol-gel method and epitaxial shell growth method.Compared with ZnO and Cu₂O,the core-shell structure enhanceed the interface between Cu₂O（111）and Cu₂O（200）facet,and increased the electrochemical active area of the catalyst.By adjusting the thickness of the Cu₂O shell,the distribution of the products can be systematically controlled.The ZnO@4Cu₂O catalyst that the molar ratio of ZnO core to Cu₂O shell is1:4 has a suitable shell thickness,which significantly enhances the CO coupling process.The best C₂ product selectivity on ZnO@4Cu₂O reached 49.8%（33.5%ethylene,16.3%ethanol）at-1.0 V vs RHE,and the total current density reached 140.1 m A cm^-2.The effect of the structure of Cu₂O and ZnO dual-site catalysts on the performance of ECR was investigated.A Cu₂O catalyst modified by ZnO dot（QD）,which was prepared with a two-step precipitation method.Due to the introduction of quantum dots,the synergy formed between Cu₂O and ZnO enhances the selectivity and current density of C₂ products.In flow cell,the selectivity of C₂ products on the ZnO/9Cu₂O catalyst reached 47.2%,and the current density increased to 170.5 m A cm^-2.In order to further improve the selectivity of C₂ products,a dual-site catalyst（x Cu₂O/y NPC）with Cu₂O supported was synthesized by wet chemical method.Nitrogen-doped porous carbon with high specific surface area increases the electrochemically active area and accelerates the rate of multi-electron transfer.The effect of the synergistic effect of pyridinic N and Cu₂O on the performance of CO₂electroreduction was studied by adjusting the loading of Cu₂O.The selectivity of C₂products on Cu₂O/4NPC catalyst increased to 54.3%（ethylene 37.2%,ethanol 17.1%）,and the total current density reached 133.2 m A cm^-2 under-1.0 V vs RHE.