Enabling Stable and Salt-Free Formic Acid Production via Reactive Interface Optimization in Forward-Bias Bipolar-Membrane CO 2 Electrolyzers
Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Electrochemical conversion of CO 2 to liquid products is limited by parasitic reactions that consume products and destabilize operation. Here, we show that salt-free formic acid synthesis in a forward-bias bipolar-membrane CO 2 electrolyzer is governed by a coupled reaction-transport instability driven by parasitic anode formic acid oxidation. Operando mass spectrometry reveals that this process proceeds through CO-mediated poisoning, identifying catalyst tolerance to CO as a key descriptor of anode selectivity. Among the catalysts examined, PtRu/C preferentially promotes hydrogen oxidation over formic acid oxidation. Coupling this catalyst with transport-interface engineering improves product removal, enhances Faradaic and energy efficiency, and enables stable operation at 200 mA/cm 2 for 190 h with a voltage decay of 0.64 mV/h. Techno-economic analysis indicates an 18% reduction in minimum selling price and highlights product concentration as the dominant cost lever. These results establish a general framework for suppressing product oxidation in liquid-product electrolyzers.
Source: ACS Energy Letters
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G102163711, G1055550527, G1313983767, G1664757510, G2287611682, G262962599, G3075337988, G3589692066, G3617077676, G440252240, G4785159920, G498139845, G6234447384, G6420323319, G6848031779, G6918803902, G7021897321, G812432097, G8142658735, G834333836, G847654844, G944719100, G969889393, G993149817
OpenAlex ID: W7166702241