| Summary: | The electrochemical reduction of carbon dioxide (CO<sub>2</sub>) to value-added chemicals and fuels has attracted worldwide interest for its potential to address various contemporary global issues such as CO<sub>2</sub>-related climate change, the earth’s carbon deficit and the energy crisis. In the development of this technology, many efforts have been focused on the design of inexpensive, eco-friendly and effective catalysts. In this work, a bismuth (Bi)-based material was simply synthesized via a scalable method and fully characterized by physical, chemical and electrochemical techniques. The catalyst material consisted of Bi/Bi<sub>2</sub>O<sub>3</sub> nanoparticles and a biochar prevenient from the pyrolysis of brewed coffee waste. It was observed that the surface of the biochar was thoroughly decorated with nanoparticles. Due to its uniform surface, the biochar–BiO<sub>x</sub> electrode demonstrated good selectivity for CO<sub>2</sub> reduction, showing a faradaic efficiency of more than 90% for CO and HCOOH formation in a wide potential range. Particularly, the selectivity for HCOOH reached more than 80% from −0.9 V to −1.3 V vs the reversible hydrogen electrode and peaks at 87%. Besides the selectivity, the production rate of HCOOH also achieved significant values with a maximum of 59.6 mg cm<sup>−2</sup> h<sup>−1</sup>, implying a good application potential for biochar–BiO<sub>x</sub> material in the conversion of CO<sub>2</sub> to HCOOH.
|
|---|