Tunable Ag-Ox coordination for industrial-level carbon-negative CO2 electrolysis

The electrochemical CO₂ reduction (eCO₂RR) is promising for eliminating CO₂, generate valuable chemicals and utilize spare electricity. However, its industrialization is greatly hindered by low CO₂ single-pass conversion efficiency (SPCE) in alkaline/neutral electrolytes, and poor compatibility between the electrolysis and intermittent energy system. Herein, a carbon-negative acidic eCO₂RR system is developed using acidic-tolerant Ag based metal-organic frameworks (Ag-MOFs), achieving a high Faradaic efficiency of CO above 97 % in a broad working window of 10–400 mA cm⁻² for unsaturated Ag-O2 clusters, and a high CO₂ SPCE of 46.3 % even under industrial-level 400 mA cm⁻². Being connected to solar cells, the acidic eCO₂RR system displays a remarkable solar-to-chemical efficiency of 19.74 %, offering great potential for industrial eCO₂RR directly driven by renewable energy. Specifically, the CO/HCOOH selectivity could be manipulated by adjusting the coordination number of Ag atoms in Ag-MOFs, and thus a Pourbaix-diagram is proposed to explain the tunable selectivity theoretically.