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Bi‐based materials quickly rise as promising candidates for electrochemical CO2‐to‐formate conversion. However, most of them only display a narrow potential range for the desired formate selectivity. Herein, we designed an oxygen‐vacancy‐rich ultrasmall bismuth subcarbonate supported on reduced graphene oxide composite (Vo‐BOC/G) for electrochemical CO2‐to‐formate conversion. The Vo‐BOC/G exhibits an outstanding formate selectivity up to 100 % at −1.2 V vs. RHE and an impressive partial current density of 38 mA cm−2 in 0.1 M KHCO3. More importantly, the considerable formate selectivity (>80 %) was obtained over an impressively wide potential range of 600 mV, superior over most of reported Bi‐based electrocatalysts under the same conditions. Theoretical results show the abundant Vo defects significantly lower energy barrier for *CO2 formation, resulting in high formate selectivity over a wider potential window. This work may pave the way for Bi‐based materials application in different renewable energy‐conversion devices. [ABSTRACT FROM AUTHOR]

We developed a tandem electrocatalyst for CO2‐to‐CO conversion comprising the single Cu site co‐coordinated with N and S anchored carbon matrix (Cu‐S1N3) and atomically dispersed Cu clusters (Cux), denoted as Cu‐S1N3/Cux. The as‐prepared Cu‐S1N3/Cux composite presents a 100 % Faradaic efficiency towards CO generation (FECO) at −0.65 V vs. RHE and high FECO over 90 % from −0.55 to −0.75 V, outperforming the analogues with Cu‐N4 (FECO only 54 % at −0.7 V) and Cu‐S1N3 (FECO 70 % at −0.7 V) configurations. The unsymmetrical Cu‐S1N3 atomic interface in the carbon basal plane possesses an optimized binding energy for the key intermediate *COOH compared with Cu‐N4 site. At the same time, the adjacent Cux effectively promotes the protonation of *CO2− by accelerating water dissociation and offering *H to the Cu‐S1N3 active sites. This work provides a tandem strategy for facilitating proton‐coupled electron transfer over the atomic‐level catalytic sites. [ABSTRACT FROM AUTHOR]

The correlation between p -orbital energy level and catalytic activity of electrochemical CO 2 reduction reaction (ECRR) is rarely reported, but significantly desired for further design of highly effective main group single-atom catalysts (SACs). Herein, a series of Sn-SACs (Sn-N 3 S 1 , Sn-N 3 P 1 , Sn-N 3 B 1 , and Sn-N 4) were developed as a model system to explore structure-activity relationships of main group SACs for ECRR. Coordination environment regulation could upshift the p -band center of Sn, facilitating the adsorption of intermediates and improving the catalytic activity. Sn-N 3 S 1 with the most positive p -band center shows a 100 % Faradaic efficiency of CO (FE CO), superior over that of Sn-N 4 and other reported SACs. Notably, the catalytic performance of Sn-SACs shows a linear relationship with p -band center of Sn, indicating a high applicability of p -band center as a descriptor for catalytic performance. This work provides a new way to boost ECRR by lowering the p -orbital energy level of main group metal. [Display omitted] • This work, for the first time, provides a systematic exploration for the correlation of coordination environment and catalytic performance for main group SACs. • The p -band center of Sn atom was upshifted by introducing the secondary heteroatom coordination, promoting the adsorption of *CO 2 intermediates and boosting the catalytic performance. • The catalytic performance of Sn-based SACs shows a linear relationship with p -band center of Sn. • The Sn-N 3 S 1 with the highest p -band center shows a 100 % Faradaic efficiency of CO (FE CO) at −0.5 V vs. RHE, superior over that of Sn-N 4 (FE CO of 81.3 % at −0.6 V) and other reported SACs. [ABSTRACT FROM AUTHOR]

Highly coupled metal/dopant-incorporated carbon dyads provide a possibility to modulate the electron density of metallic materials by forming a rectifying interface, thus showing an enhanced activity in electrochemical CO 2 reduction reaction (ECRR). However, understanding the promotion effects of dopants for ECRR is limited to the prediction by theoretical interpretation and case-by-case studies. Herein, we report the direct experimental evidence that the work function, regulated by single structural factor-dopant contents, is significantly correlated to the ECRR reaction activity and kinetics. We prepared a series of PdAu/N x C electrocatalysts composed of ultrafine (∼5.7 nm) PdAu bimetallic nanoparticles and tailorable N-doped carbon supports. The wide range of the amount of N dopants allowed the modification of the band gap of the carbon easily. Using ultraviolet photoelectron spectroscopy (UPS) measurements, we demonstrate that the reactivity and kinetics trends of the PdAu/N x C in the ECRR can be intrinsically correlated with the work function of the catalysts. PdAu/N 7.50 C electrocatalyst with the highest N contents displays a 100% CO 2 -to-CO conversion and high conversion efficiency over a wide potential window, superior over other reported PdAu catalysts. This work provides a novel way to boost ECRR performance by deliberately lowering the work function of the metal/carbon electrocatalysts through the enhancement by dopants. [Display omitted] • A series of PdAu/N-rich carbon dyads were developed. • Electron transfer from NC to metal forms electron-rich regions on the PdAu nanoparticles. • PdAu nanoparticles with rich electronic structure promote the adsorption of *CO 2 and accelerate the catalytic reaction. • PdAu/N 7.50 C demonstrates an excellent CO selectivity over a wide potential range. [ABSTRACT FROM AUTHOR]