Metal oxide based chemiresistive gas sensors can effectively detect combustible, explosive and toxic gases, and have been widely used for safety monitoring and process control in residential buildings, in various industrial settings, in mines and for environmental monitoring. However, further improvements in sensitivity and selectivity are still needed for many of these gas sensors. Graphene, due to its unique characteristics (such as excellent electrical and thermal conductivity, large surface-area-to-volume ratio, and high chemical stability) is one of the most promising gas-sensing materials. However, alone, graphene exhibits minimal selectivity. This project aims to synergistically leverage the advantages of graphene and semiconducting metal oxides (SMO) to reduce or eliminate the disadvantages of either material by forming graphene/metal oxide composites. In particular, semiconducting metal oxide sensing materials such as SnO2 and ZnO are chosen to generate graphene/SMO hybrid materials. Additionally, a template method based on polystyrene sphere monolayer colloidal crystals is developed to fabricate porous thin films for enhanced performance. By determining their specific content, we aim to achieve sensitive and selective gas detection.