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Electrochemical CO2 Reduction (CO2R) can potentially allow for the sustainable production of valuable fuels and chemicals. Recently, single atom catalysts on a 2D support have been shown to be a promising catalyst candidate. Using state-of-the-art methods, we develop a model for Fe doped graphene which rationalises several critical experimental observations: the contentious origin of the pH dependence of reactivity and the dependence of current-potential relationships on active site. We show that single atom catalysts have the unique ability to stabilise different dipoles associated with critical reaction intermediates, which translates to significant shifts in activity. This provides a new rational design principle and paves the way for rigorous computation-guided catalyst design of new single atom catalysts for CO2R. File list (2) download file view on ChemRxiv SI_Dipole_field_interactions_determine_the_CO2_reducti... (3.76 MiB) download file view on ChemRxiv main.pdf (16.28 MiB)

involved, and affordable cost. [1][2][3] However, the commercial application of the sulfur cathode for the Li-S batteries is restrained by several technical barriers [4][5][6] compared with Li-ion battery. [7] First, the poor conductivity of sulfur and its reaction intermediates limit the sulfur utilization, [8] which leads to decreased energy density and power density. Second, during the charge/discharge process, there is a large volume change, resulting in rapid deterioration of the electrode structure. Various strategies have been investigated to increase electrode conductivity and to accommodate the volume expansion. [9][10][11] Last but not least, the dissolution and transport of lithium polysulfides (LiPSs) in the electrolyte result in the fatal "shuttle effect" that causes the deposition of Li 2 S on Li anode and then degrades the cycle performance. This shuttle effect could be mitigated by 1) trapping/confining the soluble LiPSs in the cathode by physical and chemical adsorption, [12][13][14][15] which prevents the transport of soluble LiPSs in the electrolyte, and 2) enhancing the kinetics of LiPS conversion reactions so that the soluble long-chain LiPS could transform to insoluble short-chain LiPS quickly, limiting the lifetime of soluble LiPS. [16,17] Therefore, a superior Li-S battery could be achieved by designing a cathode with high electricalThe lithium-sulfur (Li-S) battery is widely regarded as a promising energy storage device due to its low price and the high earth-abundance of the materials employed. However, the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox conversion result in inefficient sulfur utilization, low power density, and rapid electrode deterioration. Herein, these challenges are addressed with two strategies 1) increasing LiPS conversion kinetics through catalysis, and 2) alleviating the shuttle effect by enhanced trapping and adsorption of LiPSs. These improvements are achieved by constructing double-shelled hollow nanocages decorated with a cobalt nitride catalyst. The N-doped hollow inner carbon shell not only serves as a physiochemical absorber for LiPSs, but also improves the electrical conductivity of the electrode; significantly suppressing shuttle effect. Cobalt nitride (Co 4 N) nanoparticles, embedded in nitrogen-doped carbon in the outer shell, catalyze the conversion of LiPSs, leading to decreased polarization and fast kinetics during cycling. Theoretical study of the Li intercalation energetics confirms the improved catalytic activity of the Co 4 N compared to metallic Co catalyst. Altogether, the electrode shows large reversible capacity (1242 mAh g −1 at 0.1 C), robust stability (capacity retention of 658 mAh g −1 at 5 C after 400 cycles), and superior cycling stability at high sulfur loading (4.5 mg cm −2 ).