Switching N2O Adsorption Geometry from the O-End to the N-End on Au Nanoparticle-Decorated ZnO Enables Enhanced Sensing Performance

Nitrous oxide (N 2 O) is a potent greenhouse gas, but its chemical inertness hinders sensitive chemiresistive sensing. We demonstrate here that Au-decorated ZnO (Au-ZnO) dramatically enhances N 2 O detection. At an operating temperature of 260 ° C, the Au-ZnO sensor responds to 25 ppm N 2 O with a value of 7.6, which is a 3.8-fold enhancement over the ZnO sensor. It also exhibits high selectivity against common greenhouse gases, a lower theoretical limit of detection (0.24 ppm), a fast response time (10 s), and reliable stability. The previously elusive mechanism has been uncovered by integrating experimental characterizations and density functional theory calculations. A strong metal–support interaction, abundant oxygen vacancies at the Au-ZnO interface, and an electron-rich surface collectively switch N 2 O adsorption geometry from the O-end (physisorption on ZnO) to the N-end (weak chemisorption on Au-ZnO). This switch induces significant intramolecular charge rearrangement of N 2 O, which is crucial for enhancing the selective N 2 O sensing reaction. The abundance of reactive sites, the spillover effect, and the catalytic action of Au nanoparticles, as well as the narrowed band gap, promote N 2 O adsorption, surface reactions, and rapid charge transfer collectively. This work goes beyond the traditional oxygen-ionosorption model by showing that switching adsorption geometry and intramolecular polarization are crucial for activating inert molecules. This provides a detailed explanation of how to create high-performance N 2 O sensors.