Computational screening of M/Cu core/shell nanoparticles and their applications for the electro-chemical reduction of CO2 and CO

Abstract

To improve the catalytic activity of copper nanoparticles (Cu NPs) in the electro-chemical catalysis of the CO₂ reduction reactions (CO₂RRs), the formation and use of core/shell nanoparticles (CSNPs) with Cu as the shell composite may be an effective way. Using Cu₇₉ NP as the representative, we performed computational screening and confirmed four M_x@Cu_79−x CSNPs that can stably exist. Then, the catalytic performance of the screened CSNPs was tested through first-principles calculations. The free energy profiles indicate that Fe₁₉@Cu₆₀ is more desirable for CO₂RR catalysis due to its high selectivity for CO rather than HCOOH at a low potential. Moreover, when it electro-catalyzes CO₂ into CH₄, the Fe₁₉@Cu₆₀ CSNP exhibits much lower limiting potential (−0.58 V) compared with pure Cu₇₉ NP (−0.86 V) or the Cu (211) surface (−0.70 V). Taking the cost into consideration, the Fe₁₉@Cu₆₀ CSNP is highly recommended as a promising electro-catalyst for CO₂RRs. In addition, when CO is taken as the initial reactant to be reduced, all the screened CSNPs exhibit lower limiting potentials than Cu₇₉ NP. From the view of material design, the significant weakening of CO binding originating from the change in the d-band center could be the reason why the formation of a core/shell structure will enhance the catalytic performance of Cu NPs in CO reduction.