Metallic bismuth (Bi) shows great promise in electrocatalytic CO2 reduction into formate. However, the direct synthesis of active and stable Bi electrocatalysts remains a grand challenge. Herein, we present an in-plane confined hydrogen-reduction strategy for in situ growth of edge-modified Bi nanoribbons, which enables enhanced and stable reduction of CO2 into formate. Density functional theory calculations suggest that the synergistic effect of a preferentially exposed (113) facet and abundant Bi–O edge sites can contribute to a reduced formation energy for the formate intermediate. Moreover, in situ Raman characterizations reveal the Bi–O edge sites can remain stable during the reaction. Consequently, the Bi nanoribbons exhibit a high formate Faradaic efficiency of over 95% in a wide potential window. More impressively, a negligible degradation in selectivity and activity after more than 100 h of continuous operation can be achieved. This work provides a feasible strategy for fabricating robust catalysts for efficient CO2 reduction.

Aqueous zinc (Zn)-ion batteries have attracted increasing attentions owing to their low cost and intrinsic safety. Nevertheless, the sluggish kinetics at subzero temperatures severely exacerbate the Zn dendrite growth, which hinders their implementation in cold environments. By virtue of high activity and maximum exposure of single atoms, Bi−N 4 moieties were fabricated to serve as Zn nucleation sites to increase Zn nucleation kinetics toward high-rate and low-temperature Zn metal batteries. Benefiting from the boosted kinetics, the Bi−N 4 species render a highly reversible and dendrite-free Zn plating/stripping behavior at 5 mA cm −2 with an average Coulombic efficiency of 99.4% over 1600 cycles at −30 °C, as well as a prolonged life up to 600 cycles in symmetric cells. Low-temperature full cells were also demonstrated with nearly 100% capacity retention after cycling at 0.5 A g −1 for 1400 cycles. This work shows the feasibility of single atoms in manipulating nucleation behaviors toward low-temperature metal batteries.

Achieving high activity and selectivity of multicarbon products in the CO2 reduction reaction (CO2RR) on Cu-based electrocatalysts remains challenging due to the limited concentration of local OH–, sluggish CO2 diffusion, and competitive hydrogen evolution reaction. Herein, we report aerophilic nanocomposites of hydrophobic SiO2 aerosol and Cu2O nanocubes to tailor the microenvironment for enhancing CO2 electroreduction in 0.1 M KHCO3 aqueous electrolyte. Combined in situ infrared analysis, molecular dynamics simulations, and density functional theory calculations reveal that the composite Cu2O/SiO2 enriches the local hydroxyl by blocking the reaction between OH– and HCO3 –, accelerates CO2 diffusion coefficient (from 2.67 × 10–10 to 8.46 × 10–10 m2 s–1), and renders a lower dissociation energy of H2O than bicarbonate (0.49 vs 1.24 eV on Cu2O (111)) as compared to neat Cu2O. Consequently, Cu2O/SiO2 promotes the formation of C2+ products (Faradaic efficiency FEC2+ from 52.4 to 75.6%) and suppresses hydrogen generation (FEH2 from 30.0 to 9.6%) at −1.2 V versus reversible hydrogen electrode. The results provide insight into the selectivity improvement of CO2RR electrocatalysis by regulating the local microenvironment of alkalinity, H2O transportation, and CO2 permeability.

Metallic bismuth (Bi) holds great promise in efficient conversion of carbon dioxide (CO2) into formate, yet the complicated synthetic routes and unobtrusive performance hinder the practical application. Herein, a facile galvanic‐cell deposition method is proposed for the rapid and one‐step synthesis of Bi nanodendrites. Compared to the traditional deposition method, it is found that the special galvanic‐cell configuration can promote the exposure of low‐angle grain boundaries. X‐ray absorption spectroscopy, in situ characterizations and theoretical calculations indicate the electronical structures can be greatly tailored by the grain boundaries, which can facilitate the CO2 adsorption and intermediate formation. Consequently, the grain boundary‐enriched Bi nanodendrites exhibit a high selectivity toward formate with an impressively high production rate of 557.2 µmol h‐1 cm‐2 at −0.94 V versus reversible hydrogen electrode, which outperforms most of the state‐of‐the‐art Bi‐based electrocatalysts with longer synthesis time. This work provides a straightforward method for rapidly fabricating active Bi electrocatalysts, and explicitly reveals the critical effect of grain boundary in Bi nanostructures on CO2 reduction.

Utilizing Zn as a “fencing” agent has enabled the pyrolytic synthesis of atomically dispersed metal–nitrogen–carbon (AD-MNC) materials for broad electrocatalysis such as fuel cells, metal-air batteries, and water electrolyzers. Yet the Zn residue troubles the precise identification of the responsible sites in active service. Herein we developed a simple aerosil-assisted method for preparing AD-MNC materials to cautiously avoid the introduction of Zn. The combined analysis of extended X-ray absorption fine structure (EXAFS) and aberration-corrected high-resolution transition electron microscopy verified the atomic dispersion of Fe species in the as-made Fe-NC sample with a well-defined structure of Fe–N4. Besides, the EXAFS studies indicated the formation of oxygenated Fe–N4 moieties (O–Fe–N4) after the removal of aerosil nanoparticles. Therefore, the immobilization of Fe atoms in the carbon substrate was attributed to the heavily doping N and rich oxygen dangling species at the aerosil surface. Electrochemical measurements revealed that the as-made Fe-NC material furnished with O–Fe–N4 moieties exhibited excellent oxygen reduction reaction (ORR) performance, characterized by individually indicating ∼22 mV higher half-wave potentials, with respect to commercial Pt/C catalyst. Density functional theory (DFT) computations suggested that the dangling oxygen ligand on the Fe–N4 moiety could significantly boost the cleavage of OOH* and the reductive release of *OH intermediates, leading to the enhancement of overall ORR performance.