Artificial synthesis of polyesters at ambient condition via consecutive CO2 electrolysis and fermentation
Guiru Zhang, Ning Ji, Shiheng Lyu, Baoxin Ni, Peng Shen, Ke Ye, Yuting Wang, Xuheng Jiang, Hai Zhang, Xi Liu, Yongcheng Wang, Kun Jiang, Yongcheng Wang, Kun Jiang
Abstract
Electrochemically converting CO 2 into value-added chemicals is a promising approach to mitigate anthropogenic carbon emissions, yet largely limited to short-chained C 1 –C 3 products. Herein, we demonstrate a tandem artificial synthesis of biodegradable polyhydroxybutyrate (PHB) plastic from CO 2 building blocks. Batch synthesis of defects-enriched Bi catalyst is firstly demonstrated by plasma bombardment and following in situ electrochemical reduction, which delivers a HCOOH Faradaic efficiency above 80% at tunable concentration from 2 to 250 mM, an energy efficiency up to 41%, and a single-pass carbon conversion efficiency up to 60%. Annular dark field and second electron microscopic analysis, density functional theory (DFT) calcualtions, coupled with H-type and solid-state electrolyzer assessments, point out the vital role of defective and/or stepped Bi surface sites in promoting CO 2 -to-HCOOH conversion. Thereafter, as-synthesized high-purity HCOOH is used as the sole carbon source for C-chain growth within microbial fermentation reactor with Ralstonia eutropha , where activated formate dehydrogenase and increased metabolites related to Calvin–Benson–Bassham cycle are found to be responsible for the enhanced polyester accumulation.