Life cycle assessment of a microfluidic electrolytic cell using Bi – Sn nanoparticle catalyst and an ionic liquid electrolyte

Abstract

The electrochemical reduction of carbon dioxide (CO ₂ ) to produce formic acid is a sustainable and crucial method for combating greenhouse gas emissions and addressing global warming. This study focuses on conducting a life cycle assessment of formic acid synthesis using microfluidic electrolytic cells with Bi–Sn catalyst and [EMIM][BF ₄ ] (1‐ethyl‐3‐methylimidazolium tetrafluoroborate) as the electrolyte. Experimental input parameters and environmental impacts were assessed using OpenLCA software for life cycle assessment. The ReCiPe 2016 (H) midpoint method was utilized for the cradle‐to‐gate life cycle assessment based on a 1 kg functional unit of formic acid. Material consumption included catalysts, membranes, ionic liquids, and CO ₂ feed, while power consumption was primarily attributed to electricity generation. The overall Global Warming Potential (GWP) was estimated at 3.27 kg CO ₂ eq per kg of formic acid, with operational electricity accounting for 81% of emissions. Sensitivity analysis indicated that utilizing renewable electricity could reduce GWP by up to 76% (from 3.27 to 0.68–0.84 kg CO ₂ eq/kg). A comparison with conventional methods, such as methyl formate hydrolysis or methanol carbonylation, demonstrated the environmental advantages of the microfluidic electrolytic cell system. Key areas for improvement include sourcing renewable energy for the electricity sector, optimizing catalyst placement, and electrolyte recycling. These results support the viability of microfluidic CO ₂ electro‐reduction for formic acid production.