Silica materials are used in a wide range of applications such as catalysis, photocatalysis, CO₂ capture, and environmental remediation. These nanomaterials (NMs) have been extensively investigated since the advent of Stöber silica. However, the absence of pores and small surface area of Stöber silica limited its applications. Later, the discovery of MCM-41 type mesoporous silica using surfactants as structural directing agents became revolutionary in the field of silica NMs. This review focuses on the methods used for synthesizing mesoporous silica nanoparticles and their applications in various fields including catalysis (i.e., support for nanoparticle catalysts) and environmental remediation (CO to CO₂ conversion, volatile organic compound (VOC) removal, and CO₂ capture). The current issues/challenges in realizing the practical applications of these conventional materials are also highlighted. This review also compares the characteristics and applications of MCM-41, SBA-15, and KCC-1 to demonstrate the effect of the morphology and pore architecture of silica on the properties of silica-based NMs. The scope for future developments in the synthesis and applications of silica materials with different pore sizes and morphologies is discussed.