Multifunctional CaBi LDH/Ag-gC3N4 catalytic composite for sustainable pollution remediation and photochemical conversion into usable derivatives

Abstract

A simple methodology was devised for synthesizing the CaBi LDH/Ag-gC₃N₄ composite using eggshell-derived calcium. Composite is a potent catalyst for converting atmospheric gases into value-added derivatives and photocatalytic remediation with antimicrobial potential. An innovative CaBi LDH/Ag-gC₃N₄ was effectively fabricated using solvothermal and hydrothermal techniques and was subjected to sophisticated characterizations. Enhanced crystallinity with the intact framework of Ag-gC₃N₄ into CaBi LDH, agglomerated cloud-like structure, easy electron mobility transfer with extensive charge separation and high photocatalysis have been confirmed by characterization studies. The CaBi LDH/Ag-gC₃N₄ composite further demonstrated photocatalytic conversion of N₂ and CO₂ into NH₃ (up to 84.02 µmol/L at 45 min) and functional hydrocarbon derivatives (C₂H₆O ∼350 μmol/L and CH₃OH ∼118.2 μmol/L at 4 hr) respectively under visible light. The composite demonstrated superior photocatalytic remediation of ciprofloxacin (CPF) under visible spectrum and antibacterial efficacy against two pathogens, Escherichia coli and Staphylococcus aureus, supported by well suggested mechanism. The photoreduction mechanism of CaBi LDH/Ag-gC₃N₄ is discussed, and the CB position of g-C₃N₄ (-1.16 eV) showed comparatively having lesser value (negative) than CB of CaBi LDH (-0.73 eV). An intricate mechanism has been devised in each photocatalytic reaction to elucidate the general reactions in line with the intended reactions.