The electrochemical reduction of CO2 is a promising route for converting intermittent renewable energy into storable fuels and useful chemical products.

Carbon monoxide is the key intermediate in the electrochemical CO 2 reduction reaction and determines the overpotentials and selectivities for C 1 and C 2 products on copper electrodes. The kinetic model based on Marcus charge transfer theory was applied to understand the competing C−H and O−H bond formation pathways involved in the CO reduction reaction on different facets of copper. The electrochemical reduction of CO adopts a thermodynamics-controlled CHO* pathway on Cu(110) and Cu(211) surfaces, and it follows a kinetics-controlled COH* pathway on Cu(111) and Cu(100) surfaces. It was found that the initial competing hydrogenation of CO to produce the CHO* or COH* intermediate plays an important role in determining the catalytic activity and selectivity. The simulated potential-dependent rate constant profiles show that the catalytic activity increases as Cu(111) < Cu(110) < Cu(211) < Cu( 100). We suggest that catalyst structure engineering, aiming to decrease the onset potential of the COH* pathway with a lower reaction activation barrier, could be an effective way to promote the electrocatalytic activity of the CO reduction reaction.

The pH‐dependent surface‐enhanced Raman spectra of two typical surface sensor molecules p‐mercaptobenzoic acid (PMBA) and p‐mercaptopyridine (PMPY) were simulated by density functional theory calculations. First, the acid dissociation constants and individual surface Raman spectra of PMBA and PMPY were computed and compared with experimental results. It was found that acid dissociation constants calculated by the hybrid implicit‐explicit model and surface‐enhanced Raman scattering (SERS) spectra simulated by the explicit model most closely coincide with experimental results. Then, the pH‐dependent SERS spectra of PMBA and PMPY were obtained by overlaying the SERS of individual acid species and base species multiplied by their molar fractions, which were calculated from the acid dissociation constants. During the deprotonation process of PMBA, the Raman intensity from COOH stretching decreases and the Raman intensity from COO− stretching increases. During the protonation process of PMPY, the ν8a mode undergoes a significant blueshift and the relative Raman intensity of ν7a mode decreases. At last, pH calibration curves of PMBA and PMPY were obtained according to the simulated pH‐dependent Raman spectra, in which the logarithmic value of relative Raman intensity of characteristic peaks varies almost linearly with solution pH.

The electrochemical reduction of N2 is a promising candidate to ammonia synthesis process. Density functional theory simulations are carried out to study the reaction thermodynamics and kinetics for better understanding...

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