Evaluating electrocatalytic performance in a simple way using the paper microzones method

The green chemistry method for analyzing changes in the concentration of substances during a reaction process is an energy-saving and interesting experimental process. In this paper, the performance of electrolysis of methylene blue (MB) in NaCl electrolyte was studied using a smartphone-based paper microzones method (PMZs), and paper microzone platform was made by discarded label stickers. The linear range spanned from 1.25 mg/L to 15 mg/L for the concentration-absorbance correspondence measured via spectrophotometry, and from 1.25 mg/L to 17.5 mg/L for the concentration-R-value correspondence measured via the PMZs method. The findings revealed that the limit of detection (LOD) value of the PMZs method was 0.494 mg/L, and the limit of quantification (LOQ) value was 1.497 mg/L. Moreover, the accuracy ranking of the measured MB electrolytic change process across different channels was as follows: Red>Grey>Green>Blue. PMZs method also showed well reliability in measuring actual dye polluted wastewater. The results demonstrate the sensitivity and precision of the PMZs method, as indicated by the low LOD and LOQ values. Additionally, the accuracy ranking provides valuable insight into the performance of the method across different color channels, shedding light on the potential applications and limitations of the PMZs technique in color-based electrochemical analyses. The electrolysis reaction led to a red-shift in the absorption characteristics of MB in NaCl electrolyte, resulting in a notable change in its light absorption properties. This information is crucial for researchers and practitioners seeking to employ the PMZs method for accurate and reliable color measurements in various scientific and industrial settings.