Gas sensors are devices that detect toxic gas, combustion/explosive gas, and volatile organic compounds. Through miniaturization of sensors and advances in wireless communication technology, use of the gas sensor in mobile and healthcare applications is rapidly increasing. Mobile gas sensors require low power consumption as well as high sensing performance. In this research, the monolithic photocatalytic micro-LED gas sensor is developed. Direct integration of sensing materials onto the micro-LED platform facilitates ultra-low power (< 1mW) UV photoactivation of sensing materials. Nano-porous In2O3 sensing films are deposited via Glancing angle deposition (GLAD), resulting in the large specific surface area and high sensitivity of sensing materials.