Microenvironment-Directed Galvanostatic Base Generation for Near-Neutral Hydrolysis of a Nerve-Agent Simulant

Abstract

Organophosphate hydrolysis under near-neutral conditions is intrinsically slow and generally requires strongly basic media or tailored catalysts. Here, we demonstrate that the electrolyte microenvironment can promote hydrolysis of dimethyl 4-nitrophenyl phosphate (DMNP) through an electrochemically generated base. Chemical controls show that DMNP hydrolysis depends on the combined effects of bulk pH, phosphate speciation, electrolyte concentration, and substrate accessibility. Under galvanostatic operation, cathodic water reduction generates OH– in situ, coupling hydrogen evolution to specific-base SN2(P) hydrolysis of DMNP. Time-resolved 31P NMR shows reciprocal DMNP consumption and dimethyl phosphate formation, while complementary UV–vis spectroscopy is consistent with formation of p-nitrophenolate. Although K2HPO4 and NaClO4 provide similar DMNP conversion at the same current, phosphate lowers the required overpotential and substantially improves energy-normalized conversion efficiency. Translation to a zero-gap membrane-electrode assembly enables stable full-cell operation and quantitative DMNP consumption within 1 h in a larger-volume, flow-compatible configuration. These findings establish galvanostatic in situ base generation as a controllable and modular strategy for organophosphate treatment in near-neutral aqueous media.