Electrochemical CO2 reduction provides a promising strategy to product value-added fuels and chemical feedstocks. However, it remains a grand challenge to further reduce the overpotentials and increase current density for large-scale applications. Here, spontaneously Sn doped Bi/BiOx nanowires (denoted as Bi/Bi­(Sn)­O x NWs) with a core–shell structure were synthesized by an electrochemical dealloying strategy. The Bi/Bi­(Sn)­O x NWs exhibit impressive formate selectivity over 92% from −0.5 to −0.9 V versus reversible hydrogen electrode (RHE) and achieve a current density of 301.4 mA cm–2 at −1.0 V vs RHE. In-situ Raman spectroscopy and theoretical calculations reveal that the introduction of Sn atoms into BiO x species can promote the stabilization of the *OCHO intermediate on the Bi­(Sn)­O x surface and suppress the competitive H2/CO production. This work provides effective in situ construction of the metal/metal oxide hybrid composites with heteroatom doping and new insights in promoting electrochemical CO2 conversion into formate for practical applications.

The np-Cu@VO2-5% hybrid electrocatalyst enables a 30.1% faradaic efficiency for ethanol production and an ethanol current density of −16 mA cm−2 at −0.62 V vs. RHE, corresponding to a 4-fold increase in activity compared to bare nanoporous Cu.

Electrochemical CO 2 reduction is a promising technology for solving the CO 2 emission problems and producing value-added products. Here, we report a hierarchically porous Cu 1 Au single-atom alloy (SAA) as an efficient electrocatalyst for CO 2 reduction. Benefiting from the hierarchically porous architectures with abundant vacancies as well as three-dimensional accessible active sites, the as-prepared nanoporous Cu 1 Au SAA catalyst shows remarkable CO 2 reduction performance with nearly 100% CO Faraday efficiency in a wide potential range (−0.4 to −0.9 V vs. reversible hydrogen electrode. The in-situ X-ray absorption spectroscopy studies and density functional theory calculations reveal that the Cu-Au interface sites serve as the intrinsic active centers, which can facilitate the activated adsorption of CO 2 and stabilize the *COOH intermediate.

Recently, the spray drying technology has emerged as an effective approach in preparing battery materials due to its advantage of preparing spherical particles with excellent dispersion, [27][28][29] which typically includes atomizing the raw material slurry and dry it into spherical particles with the excellent dispersing ability through high-temperature heat flow. However, the obtained sphere typically exhibits hollow interior with low tap density and specific surface area. The inner surface is hard to contact the electrolyte effectively, resulting in the poor electrochemical performance of active material.There are several reports on the preparation of fluorine-containing cathode materials such as LiVPO 4 F and Na 3 V 2 (PO 4 ) 2 F 3 through the spray drying method. Ding et al. [30] and Sui et al. [31] prepared pure phase LiVPO 4 F with excellent electrochemical performance through a two-step spray drying method. However, it is difficult to accurately match the addition amount of LiF due to the loss of VPO 4 in the spray drying process, and the energy consuming is large. Eshraghi et al. [32] and Shen et al. [33] have successfully synthesized spherical particles of Na 3 V 2 (PO 4 ) 2 F 3 by adding excessive NaF in one-step spray drying method. However, the excessive introduction of sodium element results in the formation of inert sodium salt, which is detrimental to the electrochemical performance of Na 3 V 2 (PO 4 ) 2 F 3 /C cathode. The utilization of high-energy ball milling also destroys the spherical structure and increases the production costs.Both the two-step method and the excessive addition of NaF were used to inhibit the production of impurity. For Na 3 V 2 (PO 4 ) 2 F 3 , the loss of fluorine during the synthesis process leads to the formation of Na 3 V 2 (PO 4 ) 3 , which is also a sodium superionic conductor and possesses only one voltage plateau at 3.4 V with theoretical capacity of 117.6 mAh g −1 . However, low voltage plateau and theoretical capacity lead to low energy density. In comparison, Na 3 V 2 (PO 4 ) 2 F 3 with an average voltage of 3.9 V and theoretical capacity of 128.4 mAh g −1 exhibit a promising application value.In this work, we have successfully synthesized pure phase porous spherical Br-doped Na 3 V 2 (PO 4 ) 2 F 3 particles by a simple one-step spray drying method. The hard template fluoropolymer polytetrafluoroethylene (PTFE) and soft template surfactant cetyltrimethylammonium bromide (CTAB) were utilized as the supplement and regulative agent of fluorine in the synthesis process of Na 3 V 2 (PO 4 ) 2 F 3 /C, respectively. Their influences on the structure, morphology, and electrochemical performance of Na 3 V 2 (PO 4 ) 2 F 3 /C were also investigated systematically. The density functional theory (DFT) calculation was further used to analyze the doping effect of Br on the density of states (DOS) and the diffusion barriers of Na ions.

Electrochemical reduction of carbon dioxide (CO2) to high-value-added products is a promising strategy for mitigating the greenhouse effect and energy shortage. Designing a high-performance electrocatalyst with a low limit potential and tunable reaction path is a critical challenge for CO2 reduction. Two-dimensional (2D) nanostructured materials are considered as competitive catalysts for electrochemical reduction due to their large specific surface area and rich active sites. The current work theoretically evaluates four 2D MBene nanosheets as potential catalysts for CO2 reduction. It is found that Mo2B2 and Cr2B2 show good catalytic selectivity due to their poor hydrogen evolution reaction (HER) performance and low limit potential for CO2 reduction. We found that the Gibbs energy increase for CHO formation is the highest on all MBenes. Among them, Mo2B2 and Cr2B2 maintain a lower limit potential with values of −0.45 and −0.5 eV, respectively. The electronic structure analysis demonstrates that the electron migration from MBene substrates to the antibonding states of adsorbates can lower the Gibbs free energy of hydrogenation reactions of intermediate products.