Advancing the Preparation Strategy of High-Performance Integrated Electrodes for eCO₂RR via Sublimation

The uniform dispersion and loading of phthalocyanine molecular catalysts on conductive carbon substrates are crucial for exposing their active sites. The significant amount of solvent needed to achieve appropriate dispersion of phthalocyanine leads to the risk of reaggregation during solvent evaporation. Hence, a solventless strategy is adopted by many to bypass the use of a solvent. In this study, we showcase the deposition of transition metal phthalocyanine (TMPc) molecules onto a self-supporting conductive carbon cloth electrode using an environmentally friendly sublimation technique for efficient electrocatalytic CO₂ reduction. We meticulously investigated the preparation conditions, including the heating temperature and TMPc type, to assess their impact on the CO₂ reduction activity. The as-prepared CC-CoPc-450 electrode demonstrated an outstanding comprehensive performance, showcasing a remarkable maximum CO Faradaic efficiency (FE_CO) of 97.1% at -0.86 V with a current density of 8.3 mA cm^-2. The electrode exhibited excellent stability during the 16 h long-term eCO₂RR process. Density functional theory (DFT) calculations demonstrated the role of d-orbitals in TM-N₄ and the synergy with π-conjugation electrons in facilitating the efficient electron transfer process in eCO₂RR. This study offers a fresh perspective on the eco-friendly dispersion of TMPcs on conductive substrates and provides insights into the design of π-species macrocyclic electrocatalyst electrodes.