Catalyst Modulation Towards Electrocatalytic Carbon Dioxide Resourceization

With the rapid development of modern society,the consumption of fossil energy has increased sharply,causing energy shortages and massive emissions of greenhouse gases,especially for carbon dioxide,leading to environmental problems such as greenhouse effect.In the face of the increasingly severe environmental crisis,transformation into a clean and low-carbon energy structure is highly desired.To reduce the carbon emissions,vigorous development of carbon dioxide utilization and conversion technology is crucial.Among various techniques,carbon dioxide electroreduction(CO2RR),that is,the use of clean electricity converted from renewable energy to achieve the mild conversion of CO2 into high value-added chemicals,would provide important technical reserves for the energy structure transformation.However,currently,CO2RR process still has technical bottlenecks such as poor catalytic activity and selectivity,redundant reaction paths,and limited mass transfer kinetics,which involve key steps such as catalyst design,reaction mechanism exploration,and reactor development,limiting the improvement of reaction efficiency and industrialization process.In this dissertation,a series of controllable synthesis methods of copper(Cu)-based catalysts were developed.Starting from the geometric and electronic structure regulation of the catalyst,the reaction pathway and regulation mechanism of CO2RR were deeply explored,and a novel electrochemical reactor for efficient CO2 conversion into mono-carbon(C1)as well as double-carbon(C2)products was constructed.Subsequently,in order to further enhance the added value of CO2-derived products,a synthetic route for mild catalytic CO2 conversion to three-carbon(C3)products was also designed.This paper mainly includes the following contents.1.Starting from the modulation towards the electronic structure of the catalyst,the electronic structure of Cu is controlled by introducing heterometallic single atoms(lead,bismuth,indium)to achieve a single selective reduction of CO2 to formic acid.Combination of in situ spectroscopy and theoretical calculations revealed the*HCOO pathway and insight into selectivity variation.A solid electrolyte reactor was developed to achieve long-term stable production of pure aqueous formic acid solution.2.Starting from the control towards the geometric structure of the catalyst,the nanoconfinement effect on the carbon-carbon coupling of CO2RR was studied by adjusting the layer-number of the multi-hollow Cu nanoshells.It is revealed that with the increase of the Cu shell number,the C1 species is enriched,which promotes the C-C coupling process,thereby improving the selectivity of the C2 product,which is verified by performance evaluation.3.A reaction route design for the preparation of isopropanol by a multi-step electrochemical-chemical process including CO2RR is proposed.A lattice-stretched ruthenium-based catalyst was developed to efficiently catalyze the critical step,the electroreduction of acetone to isopropanol,and the electrochemical direct preparation of pure isopropanol was realized through the design of a novel reactor without subsequent separation.