(509w) Self-Assembled Monolayers for Electrocatalysis: A Theoretical Study of CO2 Reduction Reaction to CO over Ag
AIChE Annual Meeting
Wednesday, November 10, 2021 - 3:30pm to 5:00pm
First-principles density functional theory (DFT) calculations were performed on 4-MBN/Ag systems. DFT calculations show that the presence of 4-MBN SAMs stabilized the Ag(211) facet, a high-catalytic active facet during CO2RR-to-CO reaction (Figure 1(a)). A local high electric field near Ag induced by 4-MBN SAMs was observed and found linearly proportional to 4-MBN coverages (Figure 1(b)). The induced local electric field was able to alter electronic properties of Ag surfaces and, thus, might change thermodynamics and kinetics of the initial CO2 activation under electrocatalytic conditions (i.e., external electric fields at the electrode/electrolyte interface). We then applied an external electric field to the CO product adsorption. With 4-MBN SAMs, dipole moment and polarizability of the CO adsorption over Ag surfaces were notably influenced as shown in Figure 1(c). Additionally, we observed that 4-MBN SAMs exhibited new organic active sites to activate CO2 and stabilize OCOH*. The surface stabilization effect and electronic surface modification via 4-MBN SAMs provide a new strategy for catalyst design with high efficiency and activity.