Efficient electrosynthesis of ammonium formate from nitrate and PET waste over a Cu-doped CoP

Integrated green electrochemistry upcycles waste PET and reduces nitrate to NH 3 , coupled to produce AF. • Upcycling of waste PET to formic acid (FE 97%). • Nitrate is reduced to ammonia with a FE of 98%. • CO 2 -eq is reduced by 99.81% per ton AF vs conventional for GWP (100y, excl. biogenic carbon). • TEA shows PET upcycling with nitrate reduction to co‑produce AF yields $556.5/ton net profit. Ammonium formate (AF) is a key chemical and fundamental building block in fields such as electrolysis, capacitor industry, organic synthesis. Conventional AF production relies on fossil-fuel-derived formic acid (FA) and ammonia (NH 3 ) obtained from the energy-intensive Haber-Bosch process. This work presents a sustainable electrocatalytic route for the direct synthesis of AF via a cathode-anode synergistic electrolysis, using nitrate (NO 3 - ) wastewater and polyethylene terephthalate (PET) waste as nitrogen and carbon sources, respectively. Employing a Cu-doped CoP (Cu-CoP) bifunctional catalyst, the system simultaneously achieves cathodic NO 3 - reduction to NH 3 with a Faraday efficiency (FE) of ∼ 98%, and anodic oxidation of PET-derived ethylene glycol (EG) to FA with an FE of ∼ 97%. The resulting anode and cathode products are subsequently mixed to form AF. Mechanistic studies reveal that Cu doping induces charge redistribution and upshifts the d -band center, thereby promoting reactant adsorption and activation while reducing the energy barriers for both NO 3 - reduction and EG oxidation. Life cycle assessment (LCA) and techno-economic analysis (TEA) confirm the environmental sustainability and economic profitability of the proposed process. This work establishes an efficient and durable catalytic route for PET upcycling and wastewater treatment, converting waste into value-added chemicals to advance a circular economy. Download: Download high-res image (207KB) Download: Download full-size image This work provides a novel approach for the sustainable synthesis of AF from PET waste and industrial nitrate-containing wastewater.