Valorization of Industrial Waste Sludge via Defect Engineering: Oxygen Vacancy Mediated Enhancement in Water Splitting, Energy Storage, and Photocatalytic Performance

High Resolution Image Download MS PowerPoint Slide Sustainable management of potentially hazardous industrial waste persists as a major remediation challenge across the globe. Herein, we have demonstrated a sustainable design strategy that not only provides a remediation of industrial waste but also utilizes the same in a multifunctional manner as a strategic component of several energy and remediation-related assemblies. Precisely, waste sludge of electrochemical industries was collected and appropriately conditioned to induce lattice defects and oxygen vacancies. The conditioned sludge was adequately characterized and was revealed to possess highly enriched metallic content. Both the oxygen vacancies and the high metallic/metal oxide content enhanced the textural and electronic attributes of the sludge-derived materials, which was validated using different applications. For the energy generation aspect, the sludge material was applied to develop a hydroelectric cell, which exhibited an excellent power of 13.6 W/m 2 with an open circuit voltage of 0.9 V. Besides, the conditioned sludge was applied as a supercapacitor and displayed excellent performance with a maximum capacitance of 338 F/g, and a maximum energy density of 53 Wh/kg was observed with 91% capacitance retention up to 2000 cycles. Furthermore, the defect-engineered sludge was also tested as a photocatalytic material and performed excellently for treating a model water contaminant, methylene blue (MB), under sunlight exposure. With these outcomes, this study shows that not only industrial waste materials can be sustainably treated but they can also be strategically harnessed to develop multifunctional conjugates to tackle several critical challenges persisting in the energy and remediation related sectors.