Gas flaring reduction to syngas using layered double hydroxide based composite through photocatalytic dry reforming of methane

Abstract

Gas flaring reduction by utilizing methane for syngas production through dry gas reforming of methane is a favorable method, as compared to other syngas producing methods, as it utilizes both greenhouse gases (CO2 and CH4). Though, the dry reforming process is well studied, there are areas that are still being explored in optimizing the process. Currently, the focused area of research is improving the stability and activity of the catalysts used in the dry reforming of methane process. Activity of catalyst mainly depends upon support type, particle size, and dispersion on support, and synthesis method. Whereas catalyst deactivation is primarily due to coke deposition and sintering of metal precursor. In this work efficient well designed 2D/2D CoAl-LDH/g-C3N4 heterojunction for photocatalytic dry reforming of methane (DRM) for syngas production has been designed and fabricated. CoAl-LDH with different concentration coupled with g-C3N4 first tested for optimization of photocatalytic syngas production (CO, H2), as prepared 15 wt.% CoAl-LDH/g-C3N4 exhibited efficient syngas production with proficient selectivity for CO and H2. Productivity of H2 of 15% wt. CoAl-LDH/g-C3N4 is about 4.8 fold that of pure CoAl-LDH and for CO is about 3.8 fold than that of pure CoAl-LDH. The improved photocatalytic activity could be attributed to unique structure and abundant active sties on surface. As compared to other heterojunction, 2D/2D CoAl-LDH/g-C3N4 heterojunction exhibit batter coupling interfaces and strong interfacial interaction, which can easily suppress the photo induced charge carrier’s recombination and decreases the distance of transmission of charges. The good recyclability and efficient sorption process with different feed ratio (CH4/CO2) confirmed its stability and batter activity. Comparison with BRM process, gave opportunity to further extend the study for future improvement in shortcomings related to structure of heterojunction for better performance in BRM. Coupling CoAl-LDH with g-C3N4 in sheet-on-sheet heterostructure is an effective strategy towards syngas production through DRM process.