RESUMEN
Electrochemically converting carbon dioxide (CO2) into valuable fuels and renewable chemical feedstocks is considered a highly promising approach to achieve carbon neutrality. In this work, a robust interfacial built-in electric field (BEF) has been successfully designed and created in Bi/Bi2Te3 nanowires (NWs). The Bi/Bi2Te3 NWs consistently maintain over 90% Faradaic efficiency (FE) within a wide potential range (-0.8 to -1.2 V), with HCOOH selectivity reaching 97.2% at -1.0 V. Moreover, the FEHCOOH of Bi/Bi2Te3 NWs can still reach 94.3% at a current density of 100 mA cm-2 when it is used as a cathode electrocatalyst in a flow-cell system. Detailed in situ experiments confirm that the presence of interfacial BEF between Bi and Bi/Bi2Te3 promotes the formation of *OHCO intermediates, thus facilitating the production of HCOOH species. DFT calculations show that Bi/Bi2Te3 NWs increase the formation energies of H* and *COOH while reducing the energy barrier for *OCHO formation, thus achieving a bidirectional optimization of intermediate adsorption. This work provides a feasible scheme for exploring electrocatalytic reaction intermediates by using the BEF strategy.
RESUMEN
The practical application of electrochemical CO2 reduction reaction (CO2RR) is hindered by the competing CO production, hydrogen evolution reaction (HER), and the lack of pH-universal catalysts. Here, Te-modified Bi nanorods (Te-Bi NRs) were synthesized through in situ reconstruction of Bi2Te4O11 NRs under the CO2RR condition. Our study illustrates that the complex reconstruction process of Bi2Te4O11 NRs during CO2RR could be decoupled into three distinct steps, i.e., the destruction of Bi2Te4O11, the formation of Te/Bi phases, and the dissolution of Te. The thus-obtained Te-Bi NRs exhibit remarkably high performance in CO2RR towards formate production, showing high activity, selectivity, and stability across all pH conditions (acidic, neutral, and alkaline). In a flow cell reactor under neutral, alkaline, or acidic conditions, the catalysts achieved HCOOH Faradaic efficiencies of up to 94.3%, 96.4%, and 91.0%, respectively, at a high current density of 300 mA cm-2. DFT calculations, along with operando spectral measurements, reveal that Te manipulates the Bi sites to an electron-deficient state, enhancing the adsorption strength of the *OCHO intermediate, and significantly suppressing the competing HER and CO production. This study highlights the substantial influence of catalyst reconstruction under operational conditions and offers insights into designing highly active and stable electrocatalysts towards CO2RR.
RESUMEN
High-entropy perovskite oxides are promising materials in the field of electrocatalysis due to their advantages such as large spatial composition regulation, entropy effects, and tunable material properties. However, the preparation of high-entropy perovskite oxides with stable and controllable structures still remains challenging. Herein, we fabricated a series of high-entropy perovskite oxide porous nanotubes (PNTs) by electrospinning as efficient electrocatalysts for the nitrate reduction reaction (NO3RR). We further revealed that the different diffusion and decomposition behaviors of metal ions and polymers during the calcination process are the key to the formation of high-entropy perovskite oxide PNTs. Especially, LaSrNiCoMnFeCuO3 PNTs show excellent performance of the NO3RR, achieving the maximum NH3 Faradaic efficiency of almost 100%, yield rate of 1657.5 µg h-1 mgcat.-1, and durable stability after successive cycling, being one of the best electrocatalysts for the NO3RR. The mechanism studies show that the charge redistribution induced by the multisite synergistic effect and abundant unsaturated sites in the high-entropy perovskite oxide PNTs favors the adsorption of NO3- and key intermediates and reduces the catalytic energy barrier, thus further achieving high NO3- conversion efficiency.