Recent research on SnS2 materials aims to enhance their photocatalytic efficiency for water pollution remediation through doping and constructing heterojunctions. These methods face challenges in cost-effectiveness and practical scalability. This study synthesizes hexagonal SnS2 nanosheets of various sizes via a hydrothermal method, assessing their performance in degrading methyl orange (MO) and reducing hexavalent chromium (Cr(VI)). The results show that smaller SnS2 nanosheets exhibit higher photocatalytic efficiency under sunlight. Specifically, 50mg of small-sized nanosheets degraded 100ml of MO (10 mgL-1) in 30min and reduced Cr(VI) (10 mgL-1) in 105min. The enhanced performance is attributed to: i) an energy bandgap of 2.17eV suitable for visible light, and ii) more surface sulfur (S) vacancies in smaller nanosheets, which create electronic states near the Fermi level, reducing electron-hole recombination. This study offers a straightforward strategy for improving 2D materials like SnS2.