Promoting Electrocatalytic CO2 Reduction to CH4 by Copper Porphyrin with Donor-Acceptor Structures.

Molecular catalysts have been receiving increasingly attention in the electrochemical CO2 reduction reaction (CO2 RR) with attractive features such as precise catalytic sites and tunable ligands. However, the insufficient activity and low selectivity of deep reduction products restrain the utilization of molecular catalysts in CO2 RR. Herein, a donor-acceptor modified Cu porphyrin (CuTAPP) is developed, in which amino groups are linked to donate electrons toward the central CuN4 site to enhance the CO2 RR activity. The CuTAPP catalyst exhibited an excellent CO2 -to-CH4 electroreduction performance, including a high CH4 partial current density of 290.5 mA cm-2 and a corresponding Faradaic efficiency of 54.8% at -1.63 V versus reversible hydrogen electrode in flow cells. Density functional theory calculations indicated that CuTAPP presented a much lower energy gap in the pathway of producing *CHO than Cu porphyrin without amino group modification. This work suggests a useful strategy of introducing designed donor-acceptor structures into molecular catalysts for enhancing electrochemical CO2 conversion toward deep reduction products.

A novel catalyst for efficient electrooxidation of ethanol enabled by 3D open-structured PdCu nanocages.

Mastery over the structure at nanoscale can efficiently tune the catalytic properties of catalysts, enabling great enhancement in electrocatalytic performance toward liquid fuel electrooxidation reactions. Herein, we demonstrate a facile one-pot method for the successful fabrication of binary PdCu nanocatalysts bounded with 3D open-structured nanocages, which show the advantages of high surface areas, facile mass/electron transport, and strong synergistic effect. Impressively, the resultant 3D open-structured PdCu nanocages (NCs) show large promotion in electrocatalytic performance toward ethanol oxidation reaction (EOR) with the mass activity of 1790.8 mA mg-1, being 3.3 times higher than that of commercial Pd/C (536.2 mA mg-1). Besides, the specific activity for EOR on PdCu NCs (7.7 mA cm-2) is also comparable to many Pt-based electrocatalysts, suggesting the dramatically improved electrocatalytic activity. The outstanding electrocatalytic performance of binary PdCu catalysts is attributed to the highly open 3D nanocage structure and strong electronic effect of Pd and Cu.