Synthesis of Highly Dispersed Metal Nanoparticle-Based Heterogeneous Catalysts Via Spray Pyrolysis and Their Application to Dry Reforming of Methane Reaction

Nanosized metal and metal oxide particles in heterogeneous catalysts offer notable benefits in energy and material sciences due to their superior catalytic activity and ease of use. Traditional preparation methods, however, often face challenges in achieving uniform metal dispersion and maintaining structural durability. This study introduces spray pyrolysis as an alternative method for fabricating Ni-based catalysts with enhanced metal dispersion. Spray pyrolysis, an aerosol processing technique, converts precursor solutions into fine droplets that are rapidly heated, forming an inorganic network through fast polycondensation reactions. Metal species are trapped within the inorganic network, which limits their growth. This method is a key effect known as "kinetic quenching" to achieve better metal dispersion. Nickel catalysts supported on silica were produced using spray pyrolysis and evaluated for their performance in the dry reforming of methane, which requires uniform metal nanoparticle dispersion and stability. The spray pyrolysis method resulted in Ni nanoparticles with sizes ranging from 3 to 4 nm, significantly improving catalytic activity and resistance to carbon deposition compared to catalysts prepared via sol-gel and impregnation methods. Analysis through TEM, XRD, and Hydrogen-pulse chemisorption confirmed these improvements, while TPO-MS techniques validated the role of the kinetic quenching effect in enhancing dispersion. This work highlights the potential of spray pyrolysis to advance catalyst preparation by offering superior dispersion and stability, thereby enhancing catalytic performance.