Manjunatha Kempasiddaiah, Rajib Samanta, Ravi Kumar Trivedi, Dev Shrivastava, Brahmananda Chakraborty, Sudip Barman
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引用次数: 0
Abstract
An efficient method for reducing atmospheric CO2 involves employing electrochemical CO2 reduction reactions (ECO2RR). Within this context, the ECO2RR to formate is recognized as a highly promising pathway to produce value-added fuels and chemicals. However, the challenge lies in suppressing the evolution of CO and H2 during the electroconversion of CO2. In this regard, Bi-MOFs and their derivatives, such as N-doped carbon-supported α-Bi2O3–CNx and Bi NPs/NC, were examined as potential electrocatalysts for ECO2RR. In an aqueous bicarbonate electrolytic solution, the α-Bi2O3–CNx-600 composites demonstrated a remarkable Faradaic efficiency of 93.8% at −0.79 V vs RHE, with minimal H2 production. This efficiency was consistently maintained at an average of 91.2% over the wide potential range of −0.69 to −0.99 V vs RHE. Furthermore, high partial current densities were also achieved for α-Bi2O3–CNx-600 composites in 0.5 M KHCO3 (−42.59 mA cm–2 at −0.99 V), displaying excellent durability for over 10 h. The improved catalytic performance and selectivity were ascribed to a higher Bi loading as well as well-dispersed α-Bi2O3 within the carbon frameworks (CNx), providing abundant active sites. Moreover, a higher content of N-doping in the α-Bi2O3–CNx-600 lattice likely facilitated *OCHO generation. Density functional theory calculations were also utilized to scrutinize the reaction mechanism underlying the CO2 reduction reaction to formic acid (HCOOH) over α-Bi2O3(−120) monoclinic and Bi(012) rhombohedral composites. The computed Gibbs free energy changes associated with the reduction of CO2 to HCOOH and hydrogen (H2) formation on the α-Bi2O3 catalyst suggest a potential suppression of the hydrogen evolution reaction (HER), aligning with experimental findings. Hence, these findings suggest that the prepared α-Bi2O3–CNx-600 catalysts hold significant potential for the efficient electrochemical reduction of CO2 to fuels.
期刊介绍:
ACS Applied Energy Materials is an interdisciplinary journal publishing original research covering all aspects of materials, engineering, chemistry, physics and biology relevant to energy conversion and storage. The journal is devoted to reports of new and original experimental and theoretical research of an applied nature that integrate knowledge in the areas of materials, engineering, physics, bioscience, and chemistry into important energy applications.