Tuning A-Site Cation Deficiency in Pr0.5La0.5BaCo2O5+ δ Perovskite to Realize Large-Scale Hydrogen Evolution at 2000 mA cm-2.

Industrial-level hydrogen production from the water electrolysis requires reducing the overpotential (η) as much as possible at high current density, which is closely related to intrinsic activity of the electrocatalysts. Herein, A-site cation deficiency engineering is proposed to screen high-performance catalysts, demonstrating effective Pr0.5- xLa0.5BaCo2O5+ δ (P0.5- xLBC) perovskites toward alkaline hydrogen evolution reaction (HER). Among all perovskite compositions, Pr0.4La0.5BaCo2O5+ δ (P0.4LBC) exhibits superior HER performance along with unique operating stability at large current densities (J = 500-2000 mA cm-2 geo). The overpotential of ≈636 mV is achieved in P0.4LBC at 2000 mA cm-2 geo, which outperforms commercial Pt/C benchmark (≈974 mV). Furthermore, the Tafel slope of P0.4LBC (34.1 mV dec-1) is close to that of Pt/C (35.6 mV dec-1), reflecting fast HER kinetics on the P0.4LBC catalyst. Combined with experimental and theoretical results, such catalytic activity may benefit from enhanced electrical conductivity, enlarged Co-O covalency, and decreased desorption energy of H* species. This results highlight effective A-site cation-deficient strategy for promoting electrochemical properties of perovskites, highlighting potential water electrolysis at ampere-level current density.

One-pot synthesis and hydrogen peroxide electrochemical sensing of 3D TiO2/MnO2 nanorods assembled microspheres.

Nanorods assembled 3D microspheres of TiO2/MnO2 were prepared via a simple one-pot hydrothermal approach. The resultant composite material exhibited remarkable electrocatalytic activity for hydrogen peroxide (H2O2) in comparison to each single component. The electrochemical sensor constructed with TiO2/MnO2 exhibited a linear relationship within the range 0.0001-5.6 mmol·L-1 for H2O2. The limit of detection (LOD) and sensitivity for H2O2 were 0.03 µmol·L-1 (S/N = 3) and 316.6 µA (mmol·L-1)-1 cm-2. Moreover, this sensor can be employed to detect trace amount of H2O2 in serum and urine samples successfully, supporting an insight and strategy for a more sensitive electrochemical sensor.

CuCo2O4 nanoneedle arrays growth on carbon cloth as a non-enzymatic electrochemical sensor with low detection limit ketoprofen recognition.

An electrochemical sensor for detecting ketoprofen was constructed by in-situ grown copper cobaltate (CuCo2O4) nanoneedle arrays on a carbon cloth (CC) substrate. The resulting porous nanoneedle arrays not only expose numerous electrochemically active sites but also significantly enhance the electrochemical apparent active area and current transmission efficiency. By leveraging its electrochemical properties, the sensor achieves an impressive detection limit for ketoprofen of 0.7 pM, with a linear range spanning from 2 pM ~ 2 µM. Furthermore, the sensor exhibits remarkable reproducibility, anti-interference capabilities, and stability. Notably, the developed sensor also performed ketoprofen detection on real samples (including drug formulations and wastewater) and demonstrated excellent recognition ability. These exceptional performances can be attributed to the direct growth of CuCo2O4 nanoneedle arrays on the CC substrate, which facilitates a robust electrical connection, provides abundant electrocatalytic active sites, and expands the apparent active area. Consequently, these improvements contribute to the efficient trace detection capabilities of the ketoprofen sensor.

Synergy of Active Sites and Charge Transfer in Branched WO3/W18O49 Heterostructures for Enhanced NO2 Sensing.

Achieving reliable detection of trace levels of NO2 gas is essential for environmental monitoring and protection of human health protection. Herein, a thin-film gas sensor based on branched WO3/W18O49 heterostructures was fabricated. The optimized WO3/W18O49 sensor exhibited outstanding NO2 sensing properties with an ultrahigh response value (1038) and low detection limit (10 ppb) at 50 °C. Such excellent sensing performance could be ascribed to the synergistic effect of accelerated charge transfer and increased active sites, which is confirmed by electrochemical impedance spectroscopy and temperature-programmed desorption characterization. The sensor exhibited an excellent detection ability to NO2 under different air quality conditions. This work provides an effective strategy for constructing WO3/W18O49 heterostructures for developing NO2 gas sensors with an excellent sensing performance.

Promotion of the Efficient Electrocatalytic Production of H2O2 by N,O- Co-Doped Porous Carbon.

H2O2 generation via an electrochemical two-electron oxygen reduction (2e- ORR) is a potential candidate to replace the industrial anthraquinone process. In this study, porous carbon catalysts co-doped by nitrogen and oxygen are successfully synthesized by the pyrolysis and oxidation of a ZIF-67 precursor. The catalyst exhibits a selectivity of ~83.1% for 2e- ORR, with the electron-transferring number approaching 2.33, and generation rate of 2909.79 mmol g-1 h-1 at 0.36 V (vs. RHE) in KOH solution (0.1 M). The results prove that graphitic N and -COOH functional groups act as the catalytic centers for this reaction, and the two functional groups work together to greatly enhance the performance of 2e- ORR. In addition, the introduction of the -COOH functional group increases the hydrophilicity and the zeta potential of the carbon materials, which also promotes the 2e- ORR. The study provides a new understanding of the production of H2O2 by electrocatalytic oxygen reduction with MOF-derived carbon catalysts.

Selective detection of trace carbon monoxide at room temperature based on CuO nanosheets exposed to (111) crystal facets.

In recent years, carbon monoxide (CO) intoxication incidents occur frequently, and the sensitive detection of CO is particularly significant. At present, most reported carbon monoxide (CO) sensors meet the disadvantage of high working temperature. It is always a challenge to realize the sensitive detection of carbon monoxide at room temperature. In this study, CuO nanosheets exposed more (111) active crystal facets and oxygen vacancy defects were synthesized by a simple and environmentally friendly one-step hydrothermal method. The sensor has good comprehensive gas sensing performance, compared with other sensors that can detect CO at room temperature. The response value to 100 ppm CO at room temperature is as high as 39.6. In addition, it also has excellent selectivity, low detection limit (100 ppb), good reproducibility, moisture resistance and long-term stability (60 days). This excellent gas sensing performance is attributed to the special structural characteristics of 2D materials and the synergistic effect of more active crystal facets exposed on the crystal surface and oxygen vacancy defects. Therefore, it is expected to become a promising sensitive material for rapid and accurate detection of trace CO gas under low energy consumption, reduce the risk of poisoning, and then effectively protect human life safety.

Controllable construction of ZnFe2O4-based micro-nano heterostructure for the rapid detection and degradation of VOCs.

Micro-nano heterogeneous oxides have received extensive attention due to their distinctive physicochemical properties. However, it is a challenge to prepare the hierarchical multicomponent metal oxide nanomaterials with abundant heterogeneous interfaces in a controllable way. In this work, the effective construction of the heterogeneous structure of the material is achieved by regulating the ratio of metal salts under thermal solvent condition. Three-dimensional spheres (ZnFe2O4) constructed by zero-dimensional ultra-small nanoparticles, in particular three-dimensional hollow sea urchin spheres (ZnO/ZnFe2O4) constructed by one-dimensional nanorods and three-dimensional hydrangeas (α-Fe2O3/ZnFe2O4) assembled by two-dimensional nanosheets were obtained. The two composite materials contain a large number of heterojunctions, which enhances the sensitivity of material to volatile organic compounds gas. Among them, the α-Fe2O3/ZnFe2O4 composite shows the best sensing performance for VOCs. For example, its response to 100 ppm acetone reaches 142 at 170 °C with the response time shortened to 3 s and the detection limit falling to 10 ppb. Meanwhile, the composite material presents a degradation rate of more than 90% for VOCs at a flow rate of 20 mL/min at 170 °C. In addition, the sensing and sensitivity mechanism of the composite material are studied in detail by combining GC-MS, XPS with UV diffuse reflectance tests.

Porous Cr2O3 Architecture Assembled by Nano-Sized Cylinders/Ellipsoids for Enhanced Sensing to Trace H2S Gas.

How to achieve high sensing of Cr2O3-based sensors for harmful inorganic gases is still a challenge. To this end, Cr2O3 nanomaterials assembled from different building blocks were simply prepared by chromium salt immersion and air calcination with waste scallion roots as the biomass template. The hierarchical architecture calcined at 600 °C is constructed from nanocylinders and nanoellipsoids (named as Cr2O3-600), and also possesses multistage pore distribution for target gas accessibility. Interestingly, the synergism of two shapes of nanocrystals enables the Cr2O3-based sensor to realize highly sensitive detection of trace H2S gas. At 170 °C, Cr2O3-600 exhibits a high response of 42.8 to 100 ppm H2S gas, which is 3.45 times larger than that of Cr2O3-500 assembled from nanocylinders. Meanwhile, this sensor has a low detection limit of 1.0 ppb (S = 1.4), good selectivity, stability, and moisture resistance. These results show that the combination of nanosized cylinders/ellipsoids together with exposed (104) facet can effectively improve the sensing performance of the p-type Cr2O3 material. In addition, the Cr2O3-600 sensor shows satisfactory results for actual monitoring of the corruption process of fresh chicken.

In-situ deposition of POMA/ZnO nanorods array film by vapor phase polymerization for detection of trace ammonia in human exhaled breath at room temperature.

The o-methoxyaniline (OMA) monomer was polymerized in-situ by vapor phase polymerization to form uniform and dense poly-o-methoxyaniline (POMA) film on the surface of ZnO nanorods array film which was pre-prepared by hydrothermal method. The as-prepared POMA/ZnO composite shows the best response at 40 min of vapor phase polymerization time. The response to 100 ppm ammonia at 25 °C is 8.88. The recovery time of 136 s has a certain advantage in the reported room temperature ammonia sensors. The lowest detectable concentration is as low as 0.01 ppm. The fast recovery time and low detection limit make the sensor have broad application prospects. In order to explore the response mechanism of POMA/ZnO composite to ammonia gas, the work function of POMA and ZnO and corresponding band gap energies were tested respectively. And the effect of the formation of p-n heterostructure on gas response was further explored. The actual application test results reflect that the sensor can effectively identify NH3 in the mixed gas during the production, storage and transportation of NH3. This can provide real-time early warning of NH3 leakage. Especially, the sensor can detect trace amount of NH3 in the human body's exhaled breath which is expected to realize the preliminary screening of patients with kidney disease through the detection of exhaled breath in the medical field.

Non-enzymatic nitrite amperometric sensor fabricated with near-spherical ZnO nanomaterial.

A unique near-spherical ZnO nanostructure was synthesized by using mixed solvents composed of polyethylene glycol-400 (PEG-400) and water at the volume ratio of 12:1 via the solvo-thermal method, and it possessed an ideal morphology with higher uniformity, better dispersion and small particle size. Such ZnO was employed to modify glass carbon electrode (GCE) for the construction of electrochemical sensor, i.e. near-spherical ZnO/GCE, whose nitrite sensing performance was evaluated by Chronoamperometry (CA) and Linear Sweep Voltammetry (LSV). In order to emphasis the superior sensing property and extensive suitability for different electrochemical detection techniques, the excellent but not the same nitrite detection performance obtained from CA and LSV was individually given in detail. This sensor based on CA showed broad linearity range of 0.6 µM-0.22 mM and 0.46 mM-5.5 mM, improved sensitivity of 0.785 µA µM-1 cm-2 accompanied with low LOD of 0.39 µM. With regard to LSV, wide linearity response of 1.9 µM-0.8 mM and 1.08 mM-5.9 mM, high sensitivity of 0.646 µA µM-1 cm-2 with LOD of 0.89 µM were obtained. Meanwhile, this sensor displayed outstanding repeatability with RSD of 2.96% (n = 4), high reproducibility with low RSD (1.72%-2.35%, n = 4), strong selectivity towards nitrite with the concentration set at one-tenth of the interfering substances, ideal stability with the peak current intensity above 90% of its initial value after storage for one month and acceptable recovery of 1.72-2.35% to actual samples including ham sausage, pickle and tap water. The near-spherical ZnO nanomaterial may be a preferred candidate for the fabrication of nitrite electrochemical sensor, which may exhibit a fascinating application in terms of food analysis and environmental monitoring.

Rapid detection of H2S gas driven by the catalysis of flower-like α-Bi2Mo3O12 and its visual performance: A combined experimental and theoretical study.

Metal oxide semiconductor (MOSs) are attractive materials for the development of H2S gas sensors. However, detecting H2S with short response and recovery times while also lowering the limit of detection to sub-ppb levels remains a significant challenge. We therefore developed flower-like α-Bi2Mo3O12 microspheres for H2S gas detection that provide fast response and recovery times (3 and 22 s, respectively, for 100 ppm H2S), while also reducing the limit of detection to 1 ppb. The sensor performs well in terms of sensitivity, reproducibility, long-term stability, including humidity stability. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed that H2S dissociates readily on the reduced α-Bi2Mo3O12 surface and that Mo plays a catalytic role, accelerating the rate of H2S decomposition and enabling a fast response. Moreover, test strips containing α-Bi2Mo3O12 were also prepared, which enabled the naked eye detection of ppm-level H2S gas at room temperature; a light-yellow to orange to brown color change occurs when exposed to H2S, due to its conversion into stable sulfides. This work expands the application of α-Bi2Mo3O12 to H2S gas sensing, and provides a strategy for the use of MOSs as sensor materials for the detection of other gases.

Fast detection of NO2 by porous SnO2 nanotoast sensor at low temperature.

In order to challenge high working temperature, low response and low selectivity of present NO2 sensor, porous SnO2 nanotoasts with a large surface area (79.94 m2/g) were synthesized. Thick film sensors fabricated by the SnO2 nanotoasts exhibited a high response to NO2 gas operating at room temperature. Excellent performance for NO2 sensing gas at 50 °C, included the high response of 105.2 (10 ppm), low detection limitation of 0.1 ppm, fast response within 10 s, and wide range of 0.1-10 ppm (R2 = 0.9931). These sensors also demonstrated perfect selectivity, moisture resistance and 90 days of long-term stability. SnO2 nanotoasts sensor has excellent detection ability in actual detection. The superior response of porous SnO2 nanotoasts towards NO2 was attributed to the special porous structure with large specific surface area and oxygen vacancies in sensing material, which helped adsorption of the target gas molecules onto the sensing surfaces and transfer of the charge.

Bimetallic MOFs-derived coral-like Ag-Mo2C/C interwoven nanorods for amperometric detection of hydrogen peroxide.

Coral-like Ag-Mo2C/C-I and blocky Ag-Mo2C/C-II composites were obtained from one-step in situ calcination of [Ag(HL)3(Mo8O26)]n·nH2O [L: N-(pyridin-3-ylmethyl) pyridine-2-amine] under N2/H2 and N2 atmospheres, respectively. The coral-like morphology of Ag-Mo2C/C-I is composed of interwoven nanorods embedded with small particles, and the nano-aggregate of Ag-Mo2C/C-II is formed by cross-linkage of irregular nanoparticles. The above composites are decorated on glassy carbon electrode (GCE) drop by drop to generate two enzyme-free electrochemical sensors (Ag-Mo2C/C/GCE) for amperometric detection of H2O2. In particular, the coral-like Ag-Mo2C/C-I/GCE sensor possesses rapid response (1.2 s), high sensitivity (466.2 µA·mM-1·cm-2), and low detection limit (25 nM) towards trace H2O2 and has wide linear range (0.08 µM~4.67 mM) and good stability. All these sensing performances are superior to Ag-Mo2C/C-II/GCE, indicating that the calcining atmosphere has an important influence on microstructure and electrochemical properties. The excellent electrochemical H2O2 sensing performance of Ag-Mo2C/C-I/GCE sensor is mainly attributed to the synergism of unique microstructure, platinum-like electron structure of Mo2C, strong interaction between Mo and Ag, as well as the increased active sites and conductivity caused by co-doped Ag and carbon. Furthermore, this sensor has been successfully applied to the detection of H2O2 in human serum sample, contact lens solution, and commercial disinfector, demonstrating the potential in related fields of environment and biology. Graphical abstract.

Proteomics unravels new candidate genes of Dasypyrum villosum for improving wheat quality.

Wheat is one of the most widely grown and important food crops in the world, providing approximately 20% of the food energy and protein produced for human consumption. The progress of wheat breeding is seriously restricted by the narrow genetic basis of common wheat germplasms. Dasypyrum villosum, a wild grass species that is commonly used in wheat improvement, has many excellent traits such as disease resistance, drought resistance, cold resistance, strong tillering ability, and processing quality. In this study, we compared and analyzed the cultivated wheat variety Chinese Spring (CS) and D. villosum using comparative proteomics. A total of 883 different abundant proteins (DAPs) were identified. Some of these different abundant proteins are associated with defense and stress, such as the Gα subunit, zinc finger protein family, PR1, HSP family, LEA protein, and serpin family. And a total of 24 different abundant proteins are gluten proteins. There are also 24 different abundant proteins associated with starch and sucrose metabolism. These results will provide potential candidate genes and a foundation for further research on resistance and quality for wheat genetics and breeding. SIGNIFICANCE: Proteins are the direct functional molecules of living organisms. It is of great significance to study the function of plant related genes from the perspective of protein. In this study, proteomics methods based on iTRAQ were used to compare the proteomic differences between wheat varieties Chinese Spring (CS) and D. villosum. The results provide novel insight into improving the quality of wheat. It is helpful to search for potential candidate genes for improving wheat quality and elucidate the molecular mechanisms associated with these genes.

A rational design of layered metal-organic framework towards high-performance adsorption of hazardous organic dye.

Water pollution originating from organic dyes is endangering the survival and development of society; however, adsorbents with high capacity (>5000 mg g-1) for the fast removal (≤30 min) of Congo Red (CR) in aqueous solution have been not reported to date. In the present work, an acid-base stably layered MOF, [Cd(H2L)(BS)2]n·2nH2O (L-MOF-1, H2L = N1,N2-bis(pyridin-3-ylmethyl)ethane-1,2-diamine, BS = benzenesulfonate), was hydrothermally prepared. L-MOF-1 exhibited high-performance adsorption of CR in aqueous solution at room temperature. The experimental adsorption capacity of the L-MOF-1 adsorbent towards CR reached up to about 12 000 mg g-1 in 20 min in the pH range of 2.2-4.7, which is the best adsorbent with the highest capacity and fastest adsorption of CR to date. The spontaneous adsorption process can be described by the pseudo-second-order kinetic and Langmuir isotherm models. Meanwhile, the L-MOF-1 absorbent possessed a highly positive zeta potential in acid condition (even at pH = 2.2, zeta potential = 36.2 mV). Its good adsorption performance mainly originates from its strong electrostatic attraction with CR in acidic condition, together with diverse hydrogen bonds and ππ stacking interactions. Furthermore, the L-MOF-1 absorbent exhibited good selectivity and could be reused five times through simply washing, where its adsorption efficiency was hardly affected. Therefore, L-MOF-1 is a potential absorbent for effectively removing CR from dye wastewater.

Ionic liquid([C12mim][PF6])-assisted synthesis of TiO2 /Ti2O (PO4)2 nanosheets and the chemoresistive gas sensing of trimethylamine.

The architecture of PO43- modified 2D TiO2 nanosheets was constructed by ionic liquids (ILs)-assisted hydrothermal method. The nanosheet structure can be regulated by the addition of different amount of ionic liquid. Using the composite nanosheets  a chemoresistive gas sensor was prepared for trimethylamine (TMA) detection. Most reported TMA sensors need to be operated at a relatively high operating temperature, but in this paper, the as-synthesized PO43--modified 2D TiO2/Ti2O(PO4)2 nanosheet sensor has high response (S = 87.46), short response time (14.6 s), and good reproducibility to 100 ppm TMA gas, when the temperature is 170 °C. In contrast to the single-phase TiO2 sensor, the gas-sensing property of the composite one is obviously enhanced. Moreover, its response shows excellent linear relationship with TMA concentration from 0.2 to 500 ppm, and a detection limit of 0.2 ppm. The TMA detection mechanism was investigated by analyzing the changes of the surface adsorption oxygen content by XPS and gaseous products using gas chromatography after the sensor was in contact with TMA.

Novel neuron-network-like Cu-MoO2/C composite derived from bimetallic organic framework for highly efficient detection of hydrogen peroxide.

Fabrication of non-enzymatic electrochemical sensors based on metal oxides with low valence-state for nanomolar detection of H2O2 has been a great challenge. In this work, a novel neuron-network-like Cu-MoO2/C hierarchical structure was simply prepared by in-situ pyrolysis of 3D bimetallic-organic framework [Cu(Mo2O7)L]n [L: N-(pyridin-3-ylmethyl)pyridine-2-amine] crystals. Meanwhile, the MoO2/C nano-aggregates were also obtained by liquid phase copper etching. Subsequently, two non-enzymatic electrochemical sensors were fabricated by simple drop-coating of the above two materials on the surface of glassy carbon electrode (GCE). Electrochemical measurements indicate that the Cu-MoO2/C/GCE possesses highly efficient electrocatalytic H2O2 property during wider linear range of 0.24 µM-3.27 mM. At room temperature, the Cu-MoO2/C composite displays higher sensitivity (233.4 µA mM-1 cm-2) and lower limit of detection (LOD = 85 nM), which are 1 and 2.5 times larger than those of MoO2/C material, respectively. Such excellent ability for trace H2O2 detection mainly originates from the synergism of neuron-network-like structure, enhanced electrical conductivity and increased active sites caused by low valence-state MoO2 and co-doping of Cu and carbon, and even the interaction between Cu and Mo. In addition, the H2O2 detection in spiked human serum and commercially real samples indicates that the Cu-MoO2/C/GCE sensor has certain potential application in the fields of environment and biology.

Coral-like CoMoO4 hierarchical structure uniformly encapsulated by graphene-like N-doped carbon network as an anode for high-performance lithium-ion batteries.

Encapsulation of metal oxide anode material with hierarchical structure in graphene-like high conductivity carbon network is conducive to improving the lithium storage performance of the anode material. However, it is very challenging to rational synthesizing anode materials with such structure. Herein, a mesoporous spiny coral-like CoMoO4 (SCL-CMO) self-assembled from the mesoporous nanorods made of nanoparticles is prepared by a simple one-step solvothermal method. The layered coral-like CoMoO4@N-doped Carbon (LCL-CMO@NC) composite is synthesized by polymerization of DA on the surface of SCL-CMO at room temperature and the subsequent sintering treatment. This LCL-CMO@NC composite perfectly combines the comprehensive advantages of the spiny coral-like hierarchical architecture and the N-doped graphene-like carbon coating, which not only effectively improve the electron and Li+ ion transport dynamics and accommodate the large volume changes, but also prevent hierarchical structure aggregation and pulverization during cycle process. Therefore, LCL-CMO@NC composite exhibits superior electrochemical kinetics and stability. The reversible specific capacity remained 1321.6 and 132 mA h g-1 after 900 and 10,000 cycles at 0.4 and 5 A g-1, respectively.

Novel Two-Dimensional WO3/Bi2W2O9 Nanocomposites for Rapid H2S Detection at Low Temperatures.

Compared with single-component metal oxides, multicomponent metal oxides show good gas sensing performance in the field of gas sensing, but they still need to be further improved in terms of rapid response. In this paper, a two-dimensional flaky WO3/Bi2W2O9 composite material with a thickness of about 32.3 nm was synthesized by a simple solvothermal method. The composite has good sensing performance and selectivity toward H2S. When the operating temperature is as low as 92 °C, the response to 100 ppm H2S reaches 84.18, and the response time is 2 s, which is extremely fast due to the open system of the two-dimensional nanosheet. A combination of gas chromatography-mass spectrometry (GC-MS) and X-ray photoelectron spectroscopy (XPS) is used to analyze the changes of H2S and the surface chemistry of WO3/Bi2W2O9 composite materials; the sensing mechanism of H2S was studied by a Kelvin probe and UV diffuse reflection. Compared with the pure phase WO3 and Bi2W2O9, good gas sensing properties of the WO3/Bi2W2O9 composite may be due to its unique heterostructure. This is the first application of WO3/Bi2W2O9 in the field of gas sensing and is of great significance for the rapid detection of H2S at low temperatures for multicomponent metal oxides.

Synthesis of ZnO@poly-o-methoxyaniline nanosheet composite for enhanced NH3-sensing performance at room temperature.

Poly-o-methoxyaniline (POMA) and zinc oxide (ZnO) composites were prepared via in situ polymerization and characterized by thermogravimetry thermal analysis, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and N2 sorption measurement. The composites show different morphology when the ratio of POMA and ZnO varies. At a ratio of 2:2, the composite shows thinner nanosheet structure with smooth surface and exhibits best response to NH3 at room temperature. The ZnO@POMA nanosheet sensor shows good selectivity and a wide response range (linear ranges from 0.05-1 pmm and 10-100 ppm of NH3). The lowest detection limit reaches 0.05 ppm. The sensor exhibits good reversibility. Based on the testing results of ultraviolet diffuse reflection spectroscopy and Kelvin probe technique, the adsorption and desorption of NH3 molecules on the sensing material and the formation of p-n heterostructure between ZnO and POMA and their synergistic effects are further explained. More importantly, the sensor possessed excellent moisture resistance. The overall test results of ZnO@POMA show that the sensor has good practical applicability for detecting trace NH3 at room temperature. Graphical abstract.