Highly efficient and durable aqueous electrocatalytic reduction of CO2 to HCOOH with a novel bismuth–MOF: experimental and DFT studies

Abstract

Electrochemical reduction of carbon dioxide (ERCO₂) to low-carbon fuel and useful chemicals, which can simultaneously store renewable energy and recover CO₂ in a green manner, has proven to be a viable energy storage and conversion strategy. However, there is always a technical bottleneck in preparation of highly active, selective and stable catalysts. In this work, we hydrothermally synthesized a new type of bismuth-based organic framework (Bi–MOF) and carefully investigated it as the catalyst for ERCO₂. All the samples exhibited excellent performance and the optimized one (i.e. Bi-BTC-D) achieved a high formate Faraday efficiency (FE) up to 95.5% at −0.86 V_RHE and a current density of −11.2 mA cm⁻². Moreover, the FE has been maintained over 90.0% after 12 hours of continuous electrolysis without significant reduction. The measurement results demonstrated that the excellent performance can be attributed to the special structure of Bi-BTC-D. DFT calculations show that the Bi site of Bi-BTC-D is highly efficient for formate production with very low overpotentials. The great potential of using a Bi–MOF as a highly stable, molecularly tunable catalytic material for ERCO₂ is confirmed.