ZnO coral-like nanoplates decorated with Pd nanoparticles for enhanced VOC gas sensing

A high working temperature of the ZnO nanomaterial-based gas sensor could shorten the lifetime of the sensor and increase its power consumption. Enhancing the volatile organic compound (VOC) sensing performance of ZnO nanomaterial-based gas sensors in terms of gas response and temperature is vital for their practical application. Decoration of noble metals onto nanostructures is an effective approach for improving their sensing characteristics. Herein, hydrothermally synthesized ZnO coral-like nanoplates decorated with Pd nanoparticles are introduced to achieve the improved VOC sensing performance. The morphology, crystal structure, composition, atomic structure, and gas sensing properties of the synthesized pristine and Pd-ZnO coral-like nanoplates were investigated. The results showed a remarkable reduction of optimal working temperature from 450 degrees C for the pristine ZnO based sensor to 350 degrees C for the Pd-ZnO based sensor. The sensor response to acetone at the optimal operating temperature of 350 degrees C was improved three times by surface decoration with Pd nanoparticles. The response time and recovery time of the Pd-ZnO sensor were about three times faster than that of the pristine ZnO sensor. The Pd-ZnO sensor reached a theoretical detection limit of 17 ppt and a sensitivity of 3.5-2.5 ppm acetone at 350 degrees C. The sensor transient stability after several on/off switching cycles from air to gas revealed the effective reusability of the fabricated devices. A plausible mechanism for the VOC sensing of the porous Pd-ZnO coral-like nanoplate-based sensor is also discussed. (C) 2021 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.

Automated summary

By decorating Pd nanoparticles onto ZnO nanostructures, the optimal working temperature of the sensor can be significantly reduced, with improved response and recovery time to acetone, as well as increased sensitivity and detection limit. The Pd-ZnO sensor demonstrates effective reusability through multiple on/off switching cycles.