Conquering the issue of room temperature H₂ detection at ppm/ppb level and their fundamental sensing mechanism are vitally needed for the development of highly sensitive/selective sensing devices. Herein, a strategy is proposed to synthesize 2D ZnO holey nanosheets by engineering the tunable pore/hole size with controlled oxygen vacancies using the annealing process for H₂ detection at room temperature. 2D ZnO holey nanosheets annealed at 400 °C shows a highly porous network owing to its high surface area, more channels for gas diffusion, and mass transport that exhibits improved gas-sensing performance. ZnO@400 sensor exhibits maximum response of ∼115 (20 times more than ZnO@800 sample) towards 100 ppm of H₂ at room temperature. The sensor response (recovery) times of the order ∼9(6) secs recorded to be fastest for ZnO@400 sensor as compared to ZnO@600 (∼19(13) secs) and ZnO@800 (∼27(20) secs) sensor respectively. Further, the ZnO@400 sensor also displays superior repeatability and stability of ∼97−99% after 45 days. The involved gas sensing mechanism has also been verified by carrying out XPS measurements before and after H₂ exposure at room temperature that helps to complement the theoretical justification about room temperature metallization effect. Thus, 2D ZnO holey nanosheets turn out to be a pivotal strategy to improve the gas sensing performance due to the synergetic effect of highly porous network and large specific surface areas of 2D nanosheets. The present approach proves to be one of the best methodologies to alleviate the restacking issue of the 2D nanosheets by opening up the inaccessible surfaces.

开发高灵敏/选择性感测设备非常需要克服ppm / ppb水平的室温H ₂检测问题及其基本感应机制。在本文中，提出了一种策略，该方法是通过使用室温下检测H ₂的退火工艺，通过控制氧空位来设计可调节的孔径，从而合成2D ZnO多孔纳米片。在400°C下退火的2D ZnO多孔纳米片由于其高表面积，更多的气体扩散通道和质量传递而显示出高度多孔的网络，该物质传输显示出改进的气体传感性能。ZnO @ 400传感器对100 ppm H _2的最大响应为〜115（比ZnO @ 800样品大20倍）在室温下。与ZnO @ 600（〜19（13）sec）和ZnO @ 800（〜27（20）sec）相比，ZnO @ 400传感器的传感器响应（恢复）时间记录为约9（6）秒。 ）传感器。此外，ZnO @ 400传感器在45天后还显示出卓越的可重复性和约97-99％的稳定性。还通过在H ₂之前和之后执行XPS测量来验证所涉及的气体传感机制在室温下暴露，有助于补充有关室温金属化效应的理论依据。因此，由于2D纳米片的高度多孔网络和大比表面积的协同效应，二维ZnO多孔纳米片被证明是提高气体传感性能的关键策略。本方法被证明是通过打开难以接近的表面来减轻2D纳米片重新堆叠问题的最佳方法之一。