Process optimization and kinetic study for solar-driven photocatalytic methane bi-reforming over TiO₂/Ti₃C₂ supported CoAlLa-LDH-g-C₃N₄ dual S-scheme nanocomposite

The bireforming of methane (CH₄) with carbon dioxide (CO₂) and water, called BRM, is a process for generating syngas, which is utilized as a feed for methanol production. The formation of multi-heterojunction by hybridizing cobalt aluminum lanthanum layered double hydroxide (CoAlLa-LDH), and TiO_{2Anatase/Rutile}@Ti₃C₂ MXene (TiO_2A/R@Ti₃C₂) with graphitic carbon nitride (g-C₃N₄) to form a g-C₃N₄/TiO_2A/R@Ti₃C₂/CoAlLa-LDH dual-S-scheme composite performed as an excellent candidate for photocatalytic BRM. The photocatalytic performance was studied for CO₂ dry reforming of methane (DRM), bireforming of methane (BRM), and CO₂ reduction with H₂O. The photocatalytic BRM was found to be an efficient reforming system with high-quality syngas production. The efficiency of the BRM process was then optimized by employing Response Surface Methodology (RSM). In RSM studies, it was inferred that in the photocatalytic BRM at the feed ratio of 1.67 for (CO₂/CH₄), the CO production reached a maximum with a value of 25.24 μmol at 4.68 h; however, increasing it further caused a decrease in CO production. Furthermore, at a feed ratio of 1.41 for CO₂/CH₄, the production of H₂ reached its maximum with a value of 23.05 μmol at 4.93 h. The hydrogen-rich syngas production demonstrated excellent stability. The photocatalyst stability and regeneration characteristics were studied, demonstrating no decrease in the syngas production or quality.