Unexpected electro-catalytic activity of the CO reduction reaction on Cr-embedded poly-phthalocyanine realized by strain engineering: a computational study.

The electrochemical conversion of carbon monoxide (CO) into value-added products is highly promising for carbon utilization and CO removal. Based on previous theoretical studies, we computationally explored the effect of strain engineering on electrocatalysis of the CO reduction reaction (CORR) by two-dimensional (2D) transition metal embedded polyphthalocyanines (MPPcs). By calculating the adsorption energy of CO and the free energies of key intermediates on the MPPcs under uniaxial and biaxial strains, it was revealed that only CrPPc under biaxial strain has the potential to exhibit significant enhancement of the catalytic performance. The free energy diagrams of the CORR catalyzed by CrPPc were plotted under specific biaxial strains, where both the optimal reaction pathway and rate-determining step are found to be evidently changed. What's more, the 5% compressive strain imposed on CrPPc results in an ultra-low limiting potential (UL = -0.09 V) with high selectivity on CH4 as the final product, indicating unexpected electro-catalytic activity. Our study clearly elucidates that moderate strain could greatly enhance the electrocatalytic performance of 2D materials in the CORR.

Significance of density functional theory (DFT) calculations for electrocatalysis of N2 and CO2 reduction reactions.

Density functional theory (DFT) based computational methods have shown great significance in developing high-performance electrocatalysts. In this perspective, we briefly summarized the state-of-the-art research progress of electrocatalysts for the nitrogen reduction reaction (NRR) and CO2 reduction reaction (CO2RR), which are important processes for the conversion of common molecules into value-added products. With the help of DFT calculations, various modulation strategies are employed to improve the catalytic activity and performance of NRR and CO2RR electrocatalysts. DFT calculations are performed to confirm the surface catalytic sites, evaluate the catalytic activity, reveal the possible reaction mechanisms, and design novel structures with high catalytic performance. By discussing the currently applied computational methods and conditions during the calculations, we outlined our concerns on the prospects and future challenges of DFT calculations in electrocatalysis studies.