Developing methane (CH4) gas sensors with low working temperatures and high response has garnered substantial interest in reliably monitoring CH4 and achieving intrinsic safety. In this work, we combined photo-activation with bimetallic doping to explore CH4-sensing performance. ZnO, Pt/ZnO, and Pt@Ni/ZnO composites with different contents of Pt@Ni were synthesized. Their morphology, structure, and optical properties were characterized using various techniques. Subsequently, their CH4 sensing performance was systematically evaluated under ultraviolet (UV) illumination. The results show that the sensor based on 3Pt@Ni/ZnO composite demonstrated superior CH4 sensing performance among all sensors under UV illumination, presenting a low working temperature of 60 °C, a high response (904.04), which is approximately 60 times higher than pure ZnO (14.97) toward 5000 ppm CH4, and good response and recovery times of 4/174 s. The improved gas-sensing mechanism of the 3Pt@Ni/ZnO sensor was discussed and ascribed to the UV illumination, the synergistic effect of the bimetallic Pt@Ni, and the hollow structure of the ZnO. This study provides a promising gas-sensing material for CH4 detection at a low temperature assisted with UV illumination.
