A highly selective and durable electrocatalyst for carbon dioxide (CO2) conversion to formate is developed, consisting of tin (Sn) nanosheets decorated with bismuth (Bi) nanoparticles. Owing to the formation of active sites through favorable orbital interactions at the Sn‐Bi interface, the Bi‐Sn bimetallic catalyst converts CO2 to formate with a remarkably high Faradaic efficiency (96%) and production rate (0.74 mmol h−1 cm−2) at −1.1 V versus reversible hydrogen electrode. Additionally, the catalyst maintains its initial efficiency over an unprecedented 100 h of operation. Density functional theory reveals that the addition of Bi nanoparticles upshifts the electron states of Sn away from the Fermi level, allowing the HCOO* intermediate to favorably adsorb onto the Bi‐Sn interface compared to a pure Sn surface. This effectively facilitates the flow of electrons to promote selective and durable conversion of CO2 to formate. This study provides sub‐atomic level insights and a general methodology for bimetallic catalyst developments and surface engineering for highly selective CO2 electroreduction.

Electrochemical CO 2 reduction (CO 2 RR) using renewable energy sources represents a sustainable means of producing carbon-neutral fuels. Unfortunately, low energy efficiency, poor product selectivity, and rapid deactivation are among the most intractable challenges of CO 2 RR electrocatalysts. Here, we strategically propose a "two ships in a bottle" design for ternary Zn−Ag−O catalysts, where ZnO and Ag phases are twinned to constitute an individual ultrafine nanoparticle impregnated inside nanopores of an ultrahigh-surface-area carbon matrix. Bimetallic electron configurations are modulated by constructing a Zn−Ag−O interface, where the electron density reconfiguration arising from electron delocalization enhances the stabilization of the *COOH intermediate favorable for CO production, while promoting CO selectivity and suppressing HCOOH generation by altering the rate-limiting step toward a high thermodynamic barrier for forming HCOO*. Moreover, the pore-constriction mechanism restricts the bimetallic particles to nanosized dimensions with abundant Zn−Ag−O heterointerfaces and exposed active sites, meanwhile prohibiting detachment and agglomeration of nanoparticles during CO 2 RR for enhanced stability. The designed catalysts realize 60.9% energy efficiency and 94.1 ± 4.0% Faradaic efficiency toward CO, together with a remarkable stability over 6 days. Beyond providing a high-performance CO 2 RR electrocatalyst, this work presents a promising catalyst-design strategy for efficient energy conversion.

Microporous framework membranes with well-defined micropore structure such as metal-organic framework membranes and covalent organic framework membranes hold great promise for the enormous challenging separations in energy and environment fields.

A new tantalum-based electrocatalyst for the lithium-sulfur system is developed to overcome some key challenges in lithium-sulfur batteries. Efficient crystallinity tuning is realized via a pore-constriction mechanism in the ''ship in a bottle'' nanostructure, which offers abundant polysulfide-retaining and catalytically active sites. Oxygen vacancies in tantalum oxide manipulating electron structure with increased intrinsic conductivity function as catalytic centers to accelerate sulfur redox reactions. Excellent rate capability and cycling stability are achieved at practically relevant sulfur loadings and electrolyte content.