Copper and nickel decorated g-C3N4 as superior catalysts for reduction of toxic pollutants: A combined experimental and theoretical approach

Abstract

Catalytic reduction of pollutants employing the concept of electron-relay effect between sodium borohydride (NaBH4) and pollutant compounds, both adsorbed on catalyst surface, is one of the most effective and facile techniques among other conventional procedures. In this work, potential catalysts were developed by incorporating Cu and Ni into two-dimensional conjugated network of g-C3N4 to modify its surface properties for subsequent application in rapid degradation of hazardous waste-water pollutants. Exhaustive experiments including variation of various parameters such as catalyst-dosage, NaBH4 concentration, pollutants concentration, and pH were performed to analyse the role of metal ad-atoms, determine the best catalyst, and propose the optimum catalytic degradation conditions for each harmful pollutant and their mixtures separately for practical implementations. The as-proposed superiority of the catalyst was validated through first-principles calculations. The experimental results established the materials to be highly efficient catalysts in terms of degradation time and various catalytic parameters in reduction of a vast range of pollutants. In-depth theoretical analysis was performed to understand the role played by Cu-atom incorporation towards dye degradation mechanisms. The most feasible reaction routes for selected pollutants were identified and represented at the atomic reaction level portraying the role of NaBH4 and aqueous electrolyte in the electron-relay process.