Self-assembled 2D/2D Z-scheme heterojunction of NiAl-LDH/protonated g-C₃N₄ on conductive 2D V₂C MXene for high-performance solar-driven photocatalytic CO₂ to fuel conversion

Photocatalytic conversion of CO₂ to fuels has been contemplated as a possible way to lessen the energy and environmental dilemmas. In this work, highly conductive vanadium carbide (V₂C) MXene was coupled with protonated carbon nitride (PCN) and nickel-aluminum-layered double hydroxide (NiAl-LDH) to construct a 2D/2D/2D NiAl-LDH/V₂C/PCN Z-scheme heterojunction. The photoactivity of 2D/2D/2D NiAl-LDH/V₂C/PCN nanocomposite for the generation of CO and CH₄ attained 33.57 and 4.46 µmoles in 4 h, respectively. The photocatalytic performance for CO was 4.36 and 3.29 folds as compared to NiAl-LDH and g-C₃N₄ respectively. For CH₄ the photoactivity was 3.07 and 2.69 times greater as compared to NiAl-LDH and g-C₃N₄ respectively. PCN provides abundant protons, a high specific surface area, and efficient charge carrier separation, facilitating enhanced surface reactions. V₂C MXene acts as a conductive substrate supporting the dispersion of PCN and NiAl-LDH, serving as an electron reservoir for efficient charge separation and offering numerous active sites to boost photocatalytic CO₂ reduction under light irradiation. NiAl-LDH, when hybridized with PCN, forms robust interfacial contacts, enabling efficient heterojunction formation, superior charge transport, and high surface CO₂ availability. The improved visible light response range, rapid formation and effective separation of the generated charge carriers, and increased reactants adsorption capacity were attributed to the 2D/2D/2D NiAl-LDH/V₂C/PCN composite's increased photocatalytic activity.