Vat Dye Molecule–Proton Dual Adsorption Catalysis Based on Molybdenum Disulfide for Sustainable Textile Dyeing

The annual global output of denim exceeds a staggering 9 billion meters, valued at over $25 billion. The conventional production relies on sodium dithionite for indigo dye reduction, a costly process that also generates environmentally harmful wastewater with sulfite and sulfate ions. Addressing these issues, we present an eco-friendly, cost-effective electrochemical reduction approach using a novel molybdenum disulfide (MoS2) molecule–proton dual adsorption system for the electrocatalytic hydrogenation (ECH) of indigo dye. This system facilitates a phase shift from 2H to 1T in MoS2 by intercalating organic amine cations, enhancing the coadsorption of active hydrogen and indigo molecules, thereby boosting the ECH activity. The dimethylamine-cation intercalated MoS2 electrode material (MoS2-DMA-CF) achieves over 95% dye reduction efficiency and more than 75% faradaic efficiency in ECH, surpassing traditional methods with a 25% increase in K/S value, improved color fastness, and less than 5% color variation after 10 cycles. Additionally, this method reduces energy consumption by 92.424% and dyeing costs by 90.416%, with the dyeing wastewater exhibiting excellent biodegradability, offering substantial environmental benefits. This innovative approach not only yields significant cost savings but is also highly scalable, providing a sustainable solution for denim fabrication.