“Electro-dissolution” of gold nanoclusters for constructing ammonia sensor

Abstract

• The sensor overcomes the common obstacles in ammonia detection, the high energy barrier of ammonia electrocatalysis and the toxicity of N -ads. • Further improved the electro-dissolution mechanism for ammonia detection by theoretical analysis and expanded the application to more substances. • The economical and facile constructed sensor has excellent reproducibility under high-intensity work both in theory and practice. Overcoming the electrocatalytic energy barrier mediated by Gerischer-Mauerer's mechanism has always been a major challenge in ammonia detection. The previous report [1] that ammonia can electro-dissolve Au gives us inspiration to establish a more efficient and reusable electrochemical transmission technique for ammonia detection and, above all, remove the ammonia electrocatalytic barrier. In this work, the latent electro-dissolution activity of ammonia towards Au was employed to construct the sensing interface. The sensor applied the potentiostatic electrodeposition method to grow Au crystals on the surface of carbon cloth, offering a simple and low-cost alternative for practical production. Additionally, the electro-dissolution sensing method effectively addresses the limitation of high energy barrier and toxic products ( N -ads) in catalytic oxidation of ammonia. Cyclic Voltammetry and Tafel curve demonstrate the electrochemical properties of Au/CC and help to predict the relationship between the ammonia concentration and current through theoretical analysis, which were further confirmed by an i-t curve. We proved that the sensor has excellent reproducibility under high-intensity work in theory and it exhibits high stability over 7 weeks in practice. The economical and facile constructing electrode method and the outstanding performance in long-term reuse greatly reduce the cost. Generally, the sensor is suitable for continuous ammonia monitoring in wastewater and quantitative analysis of products by chemical companies.