A New Strategy for Photo-Electrochemical Reduction of Carbon Dioxide Using a Carbazole-BODIPY Based Metal-Free Catalyst

Abstract

In this study, a cross-linked boron dipyrromethene (BODIPY) photocatalyst containing a carbazole donor group designed for photoelectrocatalytic carbon dioxide (CO₂) reduction is synthesized and characterized. The BODIPY-based system, coated onto a platinum surface, is evaluated for its electrochemical and photocatalytic performance under light illumination. Cyclic voltammetry (CV) and chronoamperometry measurements reveals enhanced photocurrent responses, confirming the catalyst's ability to effectively drive CO₂ reduction. Gas chromatography/mass spectrometry (GC-MS) analysis identifies the formation of ethanol (C₂H₅OH) as a major reaction product, showing that its yield increased with extended reaction times. Additionally, the photocatalyst demonstrates remarkable performance with significantly increasing turnover numbers (TON) and turnover frequencies (TOF) over time, indicating stable and sustained catalytic activity. With a Faradaic efficiency of 34.79% at a potential of -1.15 V, this BODIPY system exhibits both high activity and long-term stability. The combination of efficient electron transfer and visible light absorption by the carbazole-BODIPY donor-acceptor structure positions this system as a highly promising candidate for sustainable CO₂ conversion applications.