Exploring the superior mild temperature performance of nickel-infused fibrous titania silica for enhanced dry reforming of methane

Abstract

Carbon (IV) oxide (CO2) and methane (CH4) contribute significantly to greenhouse gas emissions and global warming. One potential approach for reducing their environmental impact is transforming these gases into synthesis gas (CO + H2). This study illustrates the advancement of catalysts supported by fibrous titania silica (FTS), which have nickel loadings of 1%, 3%, and 5%. The FTS support, a modified variant of silica-titania, has a distinct fibrous structure and exhibits mesoporous material properties such as a type IV isotherm and an H1 hysteresis loop. After 72 h of operation, the 1Ni/FTS catalyst converted over 80% of CH4 and CO2 with low coke deposition, outperforming other catalysts. The bare FTS support had reduced CH4 conversion at 600°C, CO2 conversion at 650°C, and H2/CO ratio at 700°C. However, the 5Ni/FTS and 3Ni/FTS catalysts showed consistent increases in CH4 conversion at 600°C. The 1Ni/FTS catalyst, with a pore size of 7.39 nm, had strong metal-support interaction and moderate basicity sites, which helped with reactant dissociation and coke gasification. Despite the slightly higher CH4 conversion of the 3Ni/FTS catalyst and the high basicity of the 5Ni/FTS catalyst, the 1Ni/FTS catalyst demonstrated superior thermal stability and coking resistance, as evidenced by negligible weight loss during TGA analysis. Raman shifts revealed the presence of carbon synthesis and the buildup of disordered amorphous carbon. The Id/Ig ratios of FTS, 1Ni/FTS, 3Ni/FTS, and 5Ni/FTS were 1.01, 0.98, 1.01, and 1.01, respectively. The lower Id/Ig ratio of 1Ni/FTS suggests less disorder. The FTS support promises mild-temperature, carbon-neutral CH4 reforming with long-term catalytic applications. This study demonstrates the efficacy of FTS-supported catalysts in constructing long-term and efficient systems for converting greenhouse gasses.