| dc.description.abstract | With industrial development and the increasing use of fossil fuels, carbon dioxide
emissions have risen continuously, leading to issues such as global warming and climate
change. The electrochemical carbon dioxide reduction reaction (CO2RR) is a crucial
strategy for carbon capture, utilization, and storage (CCUS) of CO2 into valuable fuels.
However, CO2RR faces challenges due to its poor selectivity, and the difficulty of
conversion into high-value C2 products.
In this study, the CO2 – ethylene (C2H4) conversion of Cu catalysts is promoted by
ZnO addition and PVP modification to produce useful fuels and achieve carbon
neutrality simultaneously. The first part examines the change in product selectivity after
adding ZnO into Cu during CO2RR. At -1.0 V (vs. RHE), the main product of Cu and
ZnO is C2H4 (FEC2H4= 36.7%) and CO (FECO=76.3%), respectively. For Cu75-ZnO25/C
(Cu/Zn = 3:1), FEC2H4 significantly improves, reaching 46.5%, and representing a 20%
increase in FEC2H4 compared to Cu. However, after 7 hours, it experienced a 40%
decline, leaving the FEC2H4 at only 22%. The results show that by combining Cu with
ZnO, which generates CO, the local concentration of the key intermediate CO can be
increased, thereby enhancing the C-C coupling kinetics.
In the second part, polyvinylpyrrolidone (PVP) is introduced during the catalyst
synthesis to suppress H2 and CH4 products while maintaining FEC2H4. Cu93-ZnO7/C
PVP demonstrates remarkable stability. At -1.0 V (vs. RHE), the FEC2H4 maintains the
original value (50.2%) after 7 hours. In-situ X-ray absorption spectroscopy analysis
shows that the high C2H4 selectivity and stability of Cu93-ZnO7/C-PCP is attributable
to the stable Cuδ+ protected by PVP under CO2RR conditions. Consequently, this
provides more active sites, thereby enhancing ethylene selectivity.
Overall, the study highlights the synergistic effects of ZnO and PVP in enhancing
ii
the efficiency and stability of Cu catalysts for CO2RR, paving the way for more efficient
CO2 utilization and more sustainable fuel production technologies. | en_US |