Theoretical Screening, Regulation, and Prediction of Transition Metal Phthalocyanine Electrocatalysts for NO Reduction into NH3

The emerging electrochemical nitric oxide reaction reduction (NORR) has received great attention due to its 2-fold functions in producing NH3 and eliminating toxic NO molecule. However, developing applicable NORR electrocatalysts with good stability and low-cost features remains challenging. Herein, we combine density functional theory (DFT) and a descriptor-based method to study the catalytic performance of 3d and 4d transition metal phthalocyanine (MPc) and its derivative with axial chlorine ligand (MPc-Cl) electrocatalysts toward NORR. First, we perform DFT calculations to sample MPc/MPc-Cl candidates via a "Three-step" strategy encompassing NO adsorbability, the first hydrogenation step, and NH3 selectivity. The screened MPc-Cl is found to display remarkably lower limiting potential than MPc. Moreover, we develop a novel descriptor to correlate NORR activity, and the descriptor-predicted NORR limiting potentials are consistent with the DFT-calculated results with a correlation coefficient of 0.98. Our work not only builds a protocol to screen suitable MPc for NO-to-NH3 conversion but also provides guidance to design high-performance MPc-based electrocatalysts.