Boosted Electrochemical CO 2 Reduction via Hydrogen Sulfide Oxidation Driven Proton Diffusion

Abstract Natural gas sweetening is irrefutable in mitigating the detrimental impacts of hazardous and corrosive pollutants like carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S) on industries and the environment. Consequently, simultaneous conversion of CO 2 and H 2 S into value‐added products is of great demand, alternative to expensive and energy consuming methods. Herein, a bifunctional electrocatalyst (NiCo( x:y )S n ) utilized for CO 2 reduction reaction (CO 2 RR) and H 2 S oxidation in a tandem electrolytic cell exhibited remarkable activity toward CO 2 to methanol and ethanol with a Faradaic efficiency (F.E.) of 29.26% and 50.16%, respectively, and H 2 S electrolysis (sulfide oxidation reaction, SOR) to sulfur with 79.9% yield. Besides, co‐electrolysis viz ., anodic H 2 S oxidation strategy to facilitate the cathodic CO 2 RR with reduced energy consumption and to achieve value‐added products at both electrodes offers “ one stone‐two birds ” strategy: a pollutant remediation along with the production of value added products. Notably, a cell voltage of 0.785 V is saved by CO 2 RR‐SOR compared to conventional CO 2 RR‐OER cells with enhanced yield rates. The plausible mechanistic pathway for CO 2 RR and its enhanced electrocatalytic activity due to H 2 S oxidation by proton diffusion strategy is probed via in situ electrochemical Fourier transform infrared spectroscopy (FT‐IR) which is further supported by four probe electrochemical approach.