Bi2S3/In(OH)3 heterojunction for enhanced CO2 electroreduction to formic acid

Electroreduction of CO 2 for formic acid production has been regarded as an efficient option for CO 2 utilization. However, under high current, achieving high selectivity for formic acid is challenging, which cannot meet industrial demands. Herein, we reported a type of Bi/In(OH) 3 (BIO) heterojunction reconstructed from Bi 2 S 3 /In(OH) 3 during electrochemical process, in which In(OH) 3 was applied to modulate the electronic structure of Bi. This strategy efficiently enhanced the ∗OCHO intermediates adsorption and lead to a decent selectivity towards formic acid under high current density. BIO displays faraday efficiency of formic acid beyond 95 ​% across a wide range current density of 200–400 ​mA ​cm −2 , where the highest value reached 97.7 ​% at 400 ​mA ​cm −2 . This work clarified the mechanism of CO 2 electroreduction to HCOOH on heterojunction, guiding the design of advanced catalysts.