ZIF-L(Co) derived cobalt doped In2O3 hollow nanofibers with high surface activity for efficient formaldehyde gas sensing

Gas sensors based on semiconductor metal oxides are identified as a highly promising candidate for toxic gas detection, yet they still suffer from high operating temperature due to low surface activity at low temperature. To address this issue, we present an elaborate design for the homogeneous functionalization of ZIF-L(Co) derived cobalt (Co) catalysts into hollow In2O3 frameworks, aiming to highly activate the redox capacity and catalytic efficacy of the In2O3 sensor to HCHO gas. Benefiting from the Co catalysts doping boosts the catalytic activity and generates abundant oxygen vacancies, the optimized 1 wt% Co-doped In2O3 HNFs sensor exhibits a high response of 40.4 toward 100 ppm HCHO at a moderately low temperature of 180 degrees C, which is 4 times higher than that of pristine In2O3 HNFs. Moreover, 1 wt% Co-doped In2O3 HNFs sensor has virtues of high selectivity and excellent long-term stability for HCHO sensing. This study highlights the important influence of Co catalyst on the modulation of surface active sites of metal oxides-based sensors, inspiring the development of cost-effective sensors for indoor hazardous gas monitoring.