Lawrence Berkeley National Laboratory

Electrochemical CO 2 reduction (CO 2 RR) is a promising technology to produce value-added fuels and weaken the greenhouse effect. Plenty of efforts are devoted to exploring high-efficiency electrocatalysts to tackle the issues that show poor intrinsic activity, low selectivity for target products, and short-lived durability. Herein, density functional theory calculations are firstly utilized to demonstrate guidelines for design principles of electrocatalyst, maximum exposure of catalytic active sites for MoS 2 edges, and electron transfer from N-doped carbon (NC) to MoS 2 edges. Based on the guidelines, a hierarchical hollow electrocatalyst comprised of edge-exposed 2H MoS 2 hybridized with NC for CO 2 RR is constructed. In situ atomic-scale observation for catalyst growth is performed by using a specialized Si/SiN x nanochip at a continuous temperature-rise period, which reveals the growth mechanism. Abundant exposed edges of MoS 2 provide a large quantity of active centers, which leads to a low onset potential of ≈40 mV and a remarkable CO production rate of 34.31 mA cm −2 with 92.68% of Faradaic efficiency at an overpotential of 590 mV. The long-term stability shows negligible degradation for more than 24 h. This work provides fascinating insights into the construction of catalysts for efficient CO 2 RR.