Yingming Xu

Traditional tin dioxide (SnO₂) gas sensors suffer from high operating temperatures and poor sensing response toward ammonia (NH₃) at room temperature. Herein, flower-like CeO₂/SnO₂ n-n heterostructures are fabricated via a facile one-pot solvothermal route followed by high-temperature calcination for ppm-level NH₃ detection at room temperature. The CeO₂/SnO₂ heterostructure calcined at 800 °C presents porous flower microspheres assembled by nanoparticles. Gas-sensing measurements demonstrate that the CeO₂/SnO₂-800 sensor delivers a high response of 6.5 toward 50 ppm NH₃ at room temperature. Moreover, the sensor exhibits outstanding selectivity, reproducibility, and long-term stability over 60 days. Combined XPS, in situ FT-IR, O₂-TPD, and EPR characterizations verify that the construction of n-n heterojunctions and abundant oxygen vacancies synergistically boost the concentration of surface-adsorbed oxygen species, thus improving the NH₃ sensing performance. The CeO₂/SnO₂ heterostructure in this work offers a promising strategy for developing low-power room-temperature NH₃ gas sensors.

The application of humidity sensors in emerging fields such as human–machine interaction is rapidly expanding, placing heightened demands on sensitivity, response/recovery time, and stability. However, due to the lack of effective structural design, most existing sensing materials often fail to simultaneously satisfy these requirements. Inspired by both the wrinkled structure of a camel's nose and the regular capillary network of a dog's nose. This study designed and fabricated a Y ₂ O ₃ wrinkled nanotubular array material. X‐ray photoelectron spectroscopy (XPS) and in situ Fourier‐transform infrared spectroscopy (FT–IR) confirmed that this dual‐bionic Y ₂ O ₃ nanotube array exhibits superior water molecule adsorption characteristics. Within a range of 11%–97% RH, the sensor demonstrates high response (17448), short response/recovery times (0.54/3.26 s), low hysteresis (1.4%), and excellent selectivity against interfering gases. After undergoing one hundred cycles of simulated harsh desert‑environment testing, both the sensor's microstructure and its response signals remained unchanged, confirming outstanding structural robustness. Furthermore, a visual water‑source localization module fabricated via micro‑electronic printing successfully achieved timely and accurate identification of subsurface water in arid environments. This work establishes microstructure engineering based on dual‑bionic concepts as an effective design paradigm for developing highly stable and sensitive humidity sensors, thereby opening new avenues for sensing applications under extreme natural conditions.

It is crucial to develop a gas sensor that is fast, efficient, and capable of real‐time monitoring of acetone. In this study, a cost‐effective and environmentally sustainable synthesis approach was employed to in situ fabricate ZnCo ₂ O ₄ nanowire arrays on ceramic tubes. By adjusting the etching time in NaBH ₄ solution, the content of Co ²⁺ and oxygen species concentration in ZnCo ₂ O ₄ were effectively modulated. The ZnCo ₂ O ₄ nanowire arrays sensor etched with NaBH ₄ solution for 30 min (ZCO‐30) exhibited a high response of 42.1 toward 100 ppm acetone at 130°C, a recovery time of 13 s, and a detection limit as low as 100 ppb. The sensor also demonstrated excellent reproducibility, humidity resistance, and long‐term stability. This excellent sensing performance is attributed to the unique array structure of ZnCo ₂ O ₄ , abundant Co ²⁺ , oxygen vacancies, and the content of surface‐adsorbed oxygen species.

Introducing oxygen vacancies has emerged as an essential strategy to affect the sensing properties of nanomaterials. However, existing methods for manipulating oxygen require high cost, complex operation, and harsh conditions. Herein, a simple NH ₄ ⁺ ‐assisted heat treatment approach was designed to regulate the concentration of oxygen vacancies of ammonium tungsten bronze ((NH ₄ ) _0.25 WO ₃ , named as NWO). The resultant NWO‐300 sensor exhibited an extremely high response of 118 to 1 ppm NO ₂ at 40°C. It achieved a detection limit as low as 10 ppb. Such outstanding sensing properties of NWO‐300 were ascribed to the modulated electronic structure and increased active sites caused by oxygen vacancies. The formation of a large number of oxygen vacancies in NWO‐300 is due to the H and N atoms in NH ₃ can extract O atoms on the surface of materials, which was confirmed by X‐ray photoelectron spectroscopy (XPS) and thermogravimetric‐mass spectrometry (TG‐MS) techniques. Moreover, the excellent NO ₂ detection ability of the NWO‐300 sensor enables the detection of air quality under different floors, and its development can be utilized in the field of environmental monitoring applications.

A dual conditioning strategy of “ligand induced-pyrolysis synergy” provides a CeO₂ humidity sensing material with oxygen-rich vacancies, which enables dynamic monitoring of food from undercooked to overcooked.