The increase of the greenhouse gas CO2 in the atmosphere has resulted in serious global warming issues. The electroreduction of CO2 to organic molecules is a critical goal that would positively impact the global carbon balance by recycling CO2 back into usable fuels. However, an electroreduction that is fast enough and can operate to full capacity remains a great scientific challenge.
This collaborative team proposes to investigate a novel class of carbon nanotube (CNT) encapsulated Cu-based nanostructures for efficient electrocatalytic reduction of CO2 in gas diffusion phase, based on their extensive research expertise in catalysis, spectroscopy and electrochemical engineering. The research hypotheses are: 1) that inside CNT channels, CO2 and H species transport and charge transfer can be effectively tuned through optimizing the diameter and length of CNTs and distribution of metal nanoparticles; 2) that the spatial restriction of CNT channels can enhance chain growth probability (to form C2+ fuels); 3) that the cation exchange ionomer can effectively adjust the local pH of reaction sites close to neutral in order to facilitate CO2 reduction. The project will focus on three research tasks: 1) rationally design, accurately synthesize and fully characterize CNTs encapsulated Cu- based bimetallic (Fe, Ag, Pd, etc) nanoparticles having alloy or core-shell structure; 2) investigate mechanistic steps of CO2 reduction at the encapsulated catalyst-cation exchange membrane ionomer interface using in-situ electrochemical FTIR, gas chromatography-mass spectrometry and high performance liquid chromatography; 3) assemble encapsulated catalysts into MEAs and investigate CO2 reduction in gas diffusion electrode environment using electrochemical methods, chromatography analysis, and micro-kinetic modeling.
This research will have several broad scientific and social impacts. First, studies of these novel encapsulated catalytic systems will advance knowledge of precise synthesis of composite catalytic materials and structure-catalytic function relationships. Second, the research efforts will deepen our understanding of electro-driven conversion of CO2 to usable organic fuels (electrofuels). Third, it will advance CO2 conversion knowledge based on solid polymer electrolyte and gas diffusion electrode techniques and support the world-wide research efforts to balance global carbon cycling and alleviate global climate change issues. The students involved will not only acquire hands-on research skills, but also learn analytical, communication, cooperation and innovation skills. In addition, the PIs will incorporate the generated results into the existing undergraduate courses and enterprise projects. The outreach efforts will increase high school students? interests in science, engineering and technology, and eventually benefit our society by a sustainably supply of new generation researchers in these fields.
