Next Article in Journal
In-Depth Investigation of the Chemical Profile of Pelargonium odoratissimum (L.) L’Hér. Hydrolate by SPME-GC/MS, GC/MS, LVI-GC/MS and PTR-Tof-MS Techniques
Previous Article in Journal
Multivariate Calibration for Selective Analysis of Hydrogen Sulfide and Carbon Monoxide with Thermal Modulation of the SnO2–PdO Sensor
Previous Article in Special Issue
Optimized SILAR Growth of Vertically Aligned ZnO Nanorods for Low-Temperature Acetone Detection
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Chemosensors
Volume 13
Issue 9
10.3390/chemosensors13090324
chemosensors-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Oxygen Vacancy-Engineered Cu2O@CuS p–p Heterojunction Gas Sensor for Highly Sensitive n-Butanol Detection

by
Di Zhang
1,2,†,
Zhengfang Qu
2,†,
Chenchen Li
1,
Huan Wang
2,
Yong Zhang
1,*,
Xiang Ren
2 and
Rui Xu
1,*
1
School of Energy and Environment Science, Yunnan Normal University, Kunming 650500, China
2
School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Chemosensors 2025, 13(9), 324; https://doi.org/10.3390/chemosensors13090324
Submission received: 29 July 2025 / Revised: 27 August 2025 / Accepted: 29 August 2025 / Published: 1 September 2025
(This article belongs to the Special Issue Functionalized Material-Based Gas Sensing)
Browse Figures
Versions Notes

Abstract

The sensitive detection of n-butanol is of high scientific and practical importance for ensuring safety in industrial production. In this study, hollow Cu2O@CuS core–shell nanocubic heterostructures were fabricated via a multistep templating method. The Cu2O@CuS heterostructures demonstrated exceptional performance, with an ultrahigh Brunauer–Emmett–Teller specific surface area that provided abundant active sites and a unique hollow architecture that enhanced mass transport and improved gas adsorption/desorption kinetics. High-density surface oxygen vacancies on the Cu2O@CuS nanocubic heterostructures provide a key structural basis for the preferential adsorption of n-butanol molecules on its surface. The p–p heterojunction configuration further enhanced selective sensor response by optimizing the charge carrier separation and band structure modulation. The developed sensor achieved a detection limit of 3.18 ppm while exhibiting outstanding sensitivity, stability, and response time, meeting the stringent requirements for n-butanol detection in both industrial and agricultural settings. This work provides new insights on how to design materials for gas sensors.

1. Introduction

As an important organic solvent and chemical raw material [1,2], n-butanol is highly flammable, explosive, and strongly corrosive, posing risks to production safety and to the health of workers who are exposed to excessive concentrations for extended periods [3]. Therefore, trace-level and sensitive detection of n-butanol is essential to promptly monitor whether its concentration exceeds safety limits [4,5], prevent harm to personnel or explosion hazards, and ensure emissions meet environmental standards, thus safeguarding production safety, worker health, and environmental sustainability.
Among various gas-sensing platforms, semiconductor-type detectors occupy a dominant position, with their working mechanism rooted in surface redox chemistry that modulates charge carrier concentrations [6]. In gas sensors based on chemiresistive mechanisms, the chemical reactions induced by target gas molecules function as sensing mechanisms that trigger measurable changes in electrical resistance [7,8]. In semiconductor gas sensors heated to operational stability, the adsorbed gas molecules remove electrons from the semiconductor surface and undergo negative ion adsorption, forming a charged surface layer [9]. Semiconductor gas sensors can reliably detect multiple gas species, such as CO, NO2, and freons, with high sensitivity, despite requiring specific work function conditions where the work function of the semiconductor must be lower than the electron affinity of adsorbed molecules [10,11].
Studies have focused on optimizing gas sensor performance by incorporating different dopants, such as noble metals and metal oxides, and by engineering structural features utilizing layered, hollow, and porous architectures [12,13]. Different engineering strategies can produce materials with distinct geometric shapes, large surface areas, and abundant unsaturated active sites, making them suitable for sensing and catalytic applications.
In the field of semiconductor gas sensors, research on gas-sensing properties has long focused on n-type semiconductor materials as the core. However, p-type semiconductor sensors have also gradually demonstrated their application potential in various scenarios due to their distinct resistance change characteristics in applications. Nanosized p-type semiconductors, including those fabricated using NiO [14,15], Cr2O3 [16], Co3O4 [17,18], ZnO [19], CuS [20], CuO [21], and Cu2O [22], have attracted growing interest due to their promising functionalities in fields other than gas sensing. Nanosized p-type semiconducting materials are applied in diverse technologies, including gas detection, energy devices, and catalytic and electrochromic systems. In particular, Cu2O exhibits p-type semiconducting properties with a bandgap of 2.17 eV, and its electrical conductivity and catalytic activity are influenced by the exposed surface areas [23]. Cu2O in various morphologies, including nanowires, nanospheres, octahedral structures, nanorods, and nanocubes, has been evaluated for gas-sensing applications. Notably, Cu2O with (111) surface planes exhibits excellent electrical conductivity [24]. However, improving the gas-sensing performance of Cu2O, a narrow-bandgap p-type semiconductor, is difficult owing to its inherent properties. One effective strategy for enhancing the gas-sensing capability of Cu2O is to design and construct a heterojunction. The p–p heterojunctions prepared via interface engineering strategies can provide strong support for the research and development of high-performance gas-sensing systems, significantly enhancing their performance stability and reliability. Recently, Azmoodeh et al. reported on p–p heterojunction-based ZnMn2O4/polypyrrole nanocomposites, with substantially enhanced hydrogen sensing performance under ambient conditions. The advantageous properties of p–p heterostructures present novel opportunities for hydrogen detection applications [25]. As a typical p-type semiconductor, CuS is widely studied for its exceptional optoelectronic properties [26]. Thus, fabricating heterojunctions by combining Cu2O and CuS for gas-sensing applications holds significant research potential; however, no studies have been reported on heterojunctions between Cu2O and CuS.
In this study, hollow Cu2O@CuS core–shell (core made of Cu2O and a shell of CuS) nanocubic heterostructures were prepared using a controllable multistep templating strategy. The highly anoxic Cu2O and defect-rich surface of CuS were anticipated to provide additional centers for n-butanol gas reactions. After the optimization of sensing conditions, the fabricated gas sensor based on Cu2O@CuS nanocubic heterostructures exhibited excellent sensing performance. In this study, a mechanism behind the sensing reaction on the surface of the fabricated gas sensor has been discussed in detail. The prepared p–p heterojunctions exhibited superior sensitivity to n-butanol compared with other volatile organic compounds (VOCs), demonstrating a successful fabrication of a highly responsive n-butanol gas sensor.

2. Experimental Section

2.1. Apparatus

X-ray diffraction (XRD, Model Smart Lab SE, Rigaku, Japan) determined the crystal structure of the sample with a Cu-Kα radiation source (λ = 1.54 Å) at a voltage of 40 kV and a current of 40 mA. The scanning range was 10°–90°, the step size was 0.02, and the speed was 10° min−1. The morphology and structure of the as-prepared samples were characterized by a field emission scanning electron microscope (FE-SEM Quanta FEG 250) and TEM (JEOL JEM 2100), facilitated with energy-dispersive X-ray spectroscopy (EDS). More information on the crystal structure and crystallinity can also be obtained by high-resolution transmission electron microscopy (HRTEM, JEM-2100F, JEOL). Information about the material elements and surface states was obtained by X-ray photoelectron spectroscopy (XPS, Smart Lab SE, Rigaku, Tokyo, Japan) analysis.

2.2. Preparation of Materials

First, a solution of CuSO4·5H2O (1.5 mmol), trisodium citrate (0.5 mmol), and deionized water (80 mL) was mixed with aqueous NaOH (20 mL, 1.25 mol/L). Next, a water-based solution of l-ascorbic acid (50 mL, 0.03 mol/L) was mixed into the reaction system, stirred for an additional 3 min, and then aged for 1 h. Subsequently, a Na2S solution (40 mL, 6.25 mmol/L) was added to a suspension of the Cu2O nanocubes (100 mg) in deionized water (60 mL) for sulfation over 30 min, followed by a centrifugation and washing cycle. The obtained Cu2O@CuS core–shell nanocubes were suspended in a 1:1 water–ethanol mixed solvent (40 mL). The produced suspension was treated with aqueous Na2S2O3 (16 mL, 1.0 mol/L) to etch Cu2O nuclei. After allowing the treated suspension to rest for 30 min, hollow Cu2O@CuS nanocubes were collected by performing multiple centrifugation and washing cycles [27].

2.3. Construction and Testing of Gas Sensor

The performance of the fabricated gas sensors was characterized using a gas-sensing measurement system. Measurement of the target gas concentration was carried out using a dynamic gas-dispersion approach. First, hollow Cu2O@CuS nanocube powder was mixed with ethanol to improve the stability of the fabricated devices, producing a suspension. The prepared suspension was uniformly applied to the surface of alumina tubes to obtain a homogeneous coating. Subsequently, the residual solvents were removed by heating and aging at an appropriate temperature for 3 h. A piece of Ni–Cr alloy wire, used as a heating element, was inserted into a ceramic tube and soldered to the base of six probes, along with four platinum wires (Figure S1). The working temperature of the fabricated thermocouple was regulated by adjusting the applied heating voltage. The produced contaminating gases were obtained by evaporating liquid ammonia, ethanol, acetone, toluene, formaldehyde, and n-butanol. The relative humidity level was maintained at 20% during the experiment. The resistance ratio R = Ra/Rg was used to quantify the gas response. Ra and Rg represent the sensor resistance in air and in the test gas, respectively. The response and recovery times of the gas sensor were determined by monitoring the time it takes for the signal to reach a 90% stabilization threshold during gas switching cycles. Different VOC concentrations were then calculated using the following formula:
C = ρ   V   R   T   P M   ×   1 atm   ×   18 L
In Equation (1), the parameters are defined as follows: C denotes the target gas concentration (ppm), ρ represents the reagent density (g/mL), V stands for the liquid volume (L), R is the gas constant (0.082 L·atm/mol·K), T is the temperature (K, 298 K), M indicates the molecular weight of the gas (g/mol), and P is the purity factor, where p is 0.25 for NH3 calculation and 0.37 for HCHO calculation. The source solutions of the other gases (CH3CH2OH, C4H10O, C3H6O, and C7H8) are of AR with P set to 1, and CO is supplied by a gas cylinder with a purity of 99.9%. The purities of gas source liquids and gas used in this study are presented in Table 1.

3. Results and Discussion

3.1. Characterization of Cu2O@CuS

The XRD data in Figure 1a shows characteristic Cu2O crystal diffraction peaks with no detectable impurities from other copper compounds [27]. The diffraction peaks align perfectly with the standard Cu2O data (PDF #05-0667). The highest intensity peak, centered at approximately 36.418°, is attributable to the (111) plane of Cu2O. The XRD pattern of Cu2O@CuS confirms the presence of both Cu2O and CuS. Specifically, diffraction peaks attributable to Cu2O are observed, along with peaks corresponding to the (103), (105), and (110) crystal planes of CuS (PDF #06-0464). Furthermore, the peak at 46.136° is assigned to the (220) crystal plane of Cu2−xS, which is understood as an indication of the presence of a heterostructure interface during the sulfidation process. In general, Cu2O with (111) crystalline surfaces exhibits high electrical conductivity, which is advantageous in various scenarios [28]. Scanning electron microscopy (SEM) imaging results in Figure 1b reveal that the Cu2O nanocubes were successfully formed, with their average size measured to be around 400 nm. Figure 1c,d show the SEM images of the hollow Cu2O@CuS nanocubes synthesized via ion exchange with a Na2S solution, followed by selective etching using sodium thiosulfate. Figure 1c,d also show that the nanocubes have a uniform size of approximately 400 nm and a relatively rough surface, endowing them with a large specific surface area. Note that an increase in the specific surface area offers more active sites for gas molecules to interact with the sensing material, enhancing gas-sensing capabilities. The transmission electron microscopy (TEM) image of the Cu2O@CuS nanocubes in Figure 1e shows a relatively brighter middle region, indicating that the prepared nanocubes are hollow.
Energy-dispersive X-ray spectroscopy (EDS) elemental mapping was used to analyze the spatial distribution of Cu, S, and O on the hollow Cu2O@CuS nanocubes. According to Figure 1f and Figure S2, all elements (Cu, S, and O) are uniformly distributed on the surfaces of the hollow Cu2O@CuS nanocubes. EDS analysis of the data presented in Table S2 reveals the weight ratio of Cu2O to CuS is 1:2.48, meaning Cu2O constitutes 28.8% and CuS 71.2% of the composite. A negligible excess of oxygen (0.86 atoms) was disregarded, confirming the material is primarily composed of these two phases.
To examine the interactions between active sites and carriers, electronic state analysis was performed. The electronic states and charge transport behavior of Cu2O and hollow Cu2O@CuS nanocubes were studied using X-ray photoelectron spectroscopy (XPS). In Figure 2a, the XPS survey scans of Cu2O and hollow Cu2O@CuS nanocubes reveal that no impurities were introduced during synthesis. In Figure 2b, the Cu 2p XPS core-level spectra show peaks at 950.90 eV (Cu 2p1/2) and 931.08 eV (Cu 2p3/2) attributable to Cu+, along with peaks at 932.88 eV (Cu 2p3/2) and 952.96 eV (Cu 2p1/2) attributable to Cu2+, indicating the presence of the two primary oxidation states of Cu in both Cu2O and Cu2O@CuS. Furthermore, the Cu (II) peak suggests the existence of a very thin oxide layer on the Cu2O surface. Notably, both the Cu 2p and O 1s XPS spectra provide complementary information about the surface chemistry of Cu2O and Cu2O@CuS. The results of Figure 2c confirm the existence of oxygen species related to oxygen vacancies, and thus infer the existence of oxygen vacancies, which can significantly enhance the catalytic reactivity of Cu2O@CuS [29,30]. Typically, oxygen vacancies on the material surface (including active sites generated by surface reconstruction) can enhance catalytic performance, promote oxygen adsorption, and thereby improve gas-sensing performance [31]. According to the values listed in Table 2, the proportion of oxygen vacancies in Cu2O@CuS (43.48%) is higher than that in Cu2O (31.3%), indicating that CuS promotes the detachment of oxygen atoms from the Cu2O lattice, thereby promoting oxygen molecule adsorption on the surface. In the S 2p XPS spectra in Figure 2d, the peaks at 160.39 and 161.56 eV are attributable to S 2p1/2 and S 2p3/2, respectively. The synergistic results of XPS and XRD confirmed the successful preparation of Cu2O@CuS.
Surface area and pore architecture represent crucial material characteristics [32]. Typically, a larger surface area in gas sensors offers greater availability of active sites, enhancing gas detection sensitivity. The porous properties of Cu2O and Cu2O@CuS were examined using nitrogen adsorption/desorption isotherm analysis. Figure 2e,f show the corresponding adsorption/desorption isotherms, pore size distributions, and summed porosity volumes. The Brunauer–Emmett–Teller (BET) surface area of Cu2O@CuS is determined as 83.1 m2/g, which is a relatively high value for promoting gas adsorption. According to the Barrett–Joyner–Halenda method, the cumulative pore volume and average pore size of Cu2O@CuS are 0.145 cm3/g and 6.99 nm, respectively. A large surface area allows for rapid gas molecule adsorption/desorption kinetics, enabling swift sensor response/recovery while improving the sensitivity.

3.2. Gas-Sensing Properties

A series of gas-sensing tests were performed to evaluate the gas-sensing performance of the hollow Cu2O@CuS nanocube-based gas sensor, particularly its ability to detect various VOCs, with a focus on n-butanol. Note that the operating temperature of a gas sensor significantly affects its sensing performance. In general, sensors require a specific operating temperature to enable optimal activity of the sensing material because target molecules often lack sufficient energy to surpass the activation barriers at relatively lower temperatures. When the operating temperature exceeds the optimal range, the sensor signal decreases. The core cause of this phenomenon is primarily the reduced reaction efficiency induced by n-butanol desorption [3]. A perfect balance between the adsorption and desorption dynamics of a target molecule on the sensor surface is achieved only at the optimal operating temperature, maximizing reaction kinetics. Furthermore, the working temperature influences both the nature of chemisorbed oxygen species and the mobility of charge carriers. Figure 3a shows that both Cu2O- and Cu2O@CuS-based sensors exhibit a temperature-dependent response toward 100 ppm n-butanol at temperatures ranging from 160 to 300 °C. Both sensors exhibit a similar response curve: initially increasing with temperature, reaching a peak at the optimal operating temperature of 260 °C, and then decreasing. Comparative analysis of the sensor responses reveals that the response of the hollow Cu2O@CuS nanocube-based sensor (58.944) toward 100 ppm n-butanol at 260 °C exceeds that of the pure Cu2O-based sensor (2.856). The superior response of the Cu2O@CuS nanocube-based sensor can be attributed to the catalytic properties of CuS nanoparticles, the presence of a heterojunction between Cu2O and CuS, a large BET-specific surface area, and high concentration oxygen vacancies. Figure 3b illustrates that the response of the hollow Cu2O@CuS nanocube-based sensor improves with the concentration of n-butanol, reaching a maximum value of 58.944 at 100 ppm. Notably, at a low concentration of 1 ppm n-butanol, the Cu2O@CuS nanocube-based sensor produces a measurable response of 2.9717. In addition, the dynamic response curve in Figure 3b demonstrates good reversible cycling properties of the Cu2O@CuS nanocube-based sensor at both low and high concentrations of incoming and outgoing n-butanol molecules. The resistance response curve in Figure 3c shows that the Cu2O@CuS nanocube-based sensor exhibits a stable baseline. The dynamic and resistive response curves in Figure 3e,f, respectively, show that the Cu2O nanocube-based gas sensor exhibits good reversible cyclability with low responses.
Stability is one of the important parameters for the practical application of gas sensors because it determines how reliably they perform over time and under varying conditions [33]. In Figure 3d, the cyclic repeatability test results show that, under the conditions of 100 ppm n-butanol and 260 °C, the hollow Cu2O@CuS nanocube-based gas sensor exhibits small differences in response peaks during multiple cycles; moreover, after each cycle ends, the sensor resistance can fall back to near the initial baseline without obvious baseline elevation, depression, or intensified fluctuation. These characteristics indicate that the sensor has a stable cyclic response and stable baseline resistance. In Figure 3h, the long-term stability test results show that the Cu2O@CuS nanocube-based gas sensor exhibits a relatively stable response over a period of 45 d, implying that the sensor possesses high long-term stability and is suitable for use in practical applications. Additionally, the Cu2O@CuS nanocube-based gas sensor exhibits a response recovery time of 54/29 s after detecting 100 ppm n-butanol, as shown in Figure 3g. Thus, the hollow Cu2O@CuS nanocube-based gas sensor is effective for applications where high response and fast recovery are needed.
Effective selectivity is a decisive factor in determining the practical utility and reliability of gas sensors under real operational conditions. The selectivity of the Cu2O@CuS nanocube-based sensor was assessed for n-butanol in the presence of several interfering gases (NH3, CO, ethanol, acetone, toluene, and formaldehyde) at a uniform concentration of 100 ppm at a sensor operating temperature of 260 °C. Notably, the Cu2O@CuS nanocube-based sensor exhibited a relatively stronger response toward 100 ppm n-butanol (Figure 3i). The excellent gas-sensing selectivity of the Cu2O@CuS heterostructure toward n-butanol stems from the synergistic effect between its surface structure and the molecular properties of n-butanol. Surface oxygen vacancies, acting as active adsorption sites, can interact with the –OH groups of n-butanol molecules to enhance adsorption. Compared with short-chain alcohols and carbonyl-containing molecules, the longer carbon chain and higher polarizability of n-butanol further stabilize adsorption through strong van der Waals forces. This synergistic effect can promote electron transfer and regulate the interfacial charge distribution, thereby significantly enhancing the sensing response. Differences in chemical affinity, molecular polarity, and adsorption–desorption kinetics enable the sensor to distinguish n-butanol from interferents to a certain extent [34]. This indicates that the sensor exhibits favorable performance in n-butanol detection and holds potential for practical applications.
Detection data were analyzed based on the classical Formula (2) for gas sensors. Figure 4a presents the correlation characteristics between the logarithm of the response value of the hollow Cu2O@CuS nanocube-based gas sensor and the logarithm of the n-butanol concentration. Through linear fitting, the relational expression lgGgas = 0.42 + 0.64 lgp was obtained; further, the formula Ggas = 2.63 p0.64 can be derived.
G gas = A   p n
To conduct an in-depth analysis of the sensing mechanism and performance limits of the hollow Cu2O@CuS nanocube gas sensor for n-butanol, the limit of detection (LOD) was calculated based on the aforementioned classical formula and fitting parameters, yielding an LOD of 3.18 ppm. This LOD index can meet the requirements of practical application scenarios for n-butanol gas detection, highlighting the excellent practical potential and certain commercial application value of the gas sensor based on this hollow-structured nanomaterial.
Under conditions of elevated humidity, adsorbed water molecules occupy the active oxygen sites on the sensor surface, thereby reducing its response. Therefore, the effects of different relative humidity (RH) conditions (the range of the RH is from 20% to 80% at ambient temperature 25 °C) on the resistance changes and response of the fabricated sensor were investigated at the optimal working temperature of 260  °C for 100 ppm n-butanol [35]. As shown in Figure 4b, the Cu2O@CuS-based gas sensor exhibits a considerably high response toward n-butanol at a relative humidity below 60%. When the ambient humidity exceeds 60%, the sensor performance slightly degrades; however, the sensor response still remains considerably high.
To demonstrate the sensor performance in this work, a comparison was conducted with previously reported n-butanol sensors. As shown in Table S3, the Cu2O@CuS sensor demonstrates superior performance, confirming that the Cu2O@CuS core–shell nanocubic heterostructure enables excellent n-butanol detection performance through the synergistic effects of ultrahigh specific surface area, hollow transport architecture, preferential adsorption by oxygen vacancies, and carrier regulation via p–p heterojunction.

3.3. Plausible Gas-Sensing Mechanism

A space charge layer model can be used to interpret the macroscopic resistance changes of the sensor. Note that the resistance of a gas sensor changes due to various processes, such as gas adsorption and desorption on the surface.
Both Cu2O (energy gap (Eg) = 1.50 eV) and CuS (Eg = 1.12 eV) are typical p-type semiconductors. The Cu atoms in the Cu2O (111) plane are asymmetrically coordinated [36]; thus, each pair of copper atoms has a dangling bond oriented perpendicular to the (111) face. Notably, compared to the (100) face, the (111) face of Cu2O has a greater number of terminal Cu atoms per unit surface area. Consequently, a higher adsorption of negative oxygen ions on the (111) face considerably improves the sensing performance of the Cu2O@CuS nanocube-based gas sensor.
The integration of CuS with Cu2O results in a p–p heterojunction, enabling carrier flow from CuS to Cu2O under the influence of a steep work function gradient until Fermi level equilibrium is reached (Figure 5). When the Cu2O@CuS heterostructure is exposed to air, O2 molecules are chemisorbed onto the material’s oxygen vacancies, with these vacancies including the active sites generated by surface reconstruction; this process further leads to the formation of oxygen anion species (Oα−), such as O2−, O−, and O2−. During the process of anion generation, the adsorbed oxygen species function as providers of hole carriers, enhancing the hole concentration in the sensing material and expanding the hole-accumulation layer at the heterojunction while thinning the depletion layer. In p-type semiconductor sensor materials, holes can flow along the grain boundaries and through the hole-accumulation layer. Therefore, potential barriers do not significantly impede the flow of holes in p-type semiconductor sensor materials, resulting in a lower baseline resistance [37]. The reaction processes involved during oxygen adsorption and anion generation are described by the following equations [38,39]:
O2 (gas) → O2 (ads)
O2 (ads) + e− → O2− (ads) (T < 100 °C)
O2− (ads) + e− → 2O− (ads) (100 °C < T < 300 °C)
O− (ads) + e− → O2− (ads) (T > 300 °C)
In the presence of n-butanol, a redox reaction occurs between the gas molecules and the previously adsorbed oxygen anions on the Cu2O@CuS p–p heterojunction, releasing electrons to the sensor surface. The recombination of released electrons with holes leads to a decrease in the charge carrier concentration within the sensing layer. Subsequently, the produced electron–hole complexes reduce the hole density in the nanocomposite and break the dynamic carrier equilibrium between Cu2O and CuS. Consequently, the hole accumulation layer thickness diminishes at the Cu2O interface while the hole depletion layer expands at the CuS interface, significantly increasing the resistance in the n-butanol environment. The following equation describes the reaction pathway between n-butanol and oxygen anions [40]:
C4H10O + 12O− (ads) → 4CO2 + 5H2O + 12e−
To summarize, hollow Cu2O@CuS nanocubes, due to their relatively high specific surface area, provide numerous active sites for negative oxygen ion adsorption. Highly anoxic Cu2O and defect-rich CuS surfaces in Cu2O@CuS nanocubes enhance their gas-sensing performance by providing abundant centers for gas reactions. The presence of a heterojunction, along with synergistic electronic effects, further improves the performance of the n-butanol sensor based on Cu2O@CuS nanocubes.

4. Conclusions

This study successfully fabricated hollow Cu2O@CuS core–shell nanocubic heterostructures and applied them to construct a gas sensor for the detection of n-butanol. The prepared sensor exhibited a low detection limit of 3.18 ppm and rapid response/recovery times of 54/29 s, respectively, enabling trace-level monitoring and quantitative analysis of n-butanol in various environments. The sensor’s excellent performance stems from multiple synergistic effects. The high specific surface area offers abundant active sites for gas adsorption; the hollow structure promotes mass transfer and accelerates adsorption/desorption kinetics; the high-density surface oxygen vacancies facilitate the preferential adsorption of n-butanol molecules, suppressing interference from other analytes; and the p–p heterojunction optimizes charge carrier separation and band structure modulation, further enhancing the selective response. During a 45-day stability test, the sensor maintained stable performance and exhibited good responsiveness under 20–80% humidity. These characteristics make the Cu2O@CuS nanocube-based sensor an ideal candidate for industrial n-butanol detection. This work highlights the great potential of heterostructure design and defect engineering in developing high-performance gas-sensing materials.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/chemosensors13090324/s1, Table S1. Reagents used in the experiments; Figure S1. Physical schematic diagram of sensor core device; Figure S2. EDS analysis of hollow Cu2O@CuS nano-cube; Table S2. EDS analysis of hollow Cu2O@CuS nano-cube; Table S3. Comparison of n-butanol gas sensors based on other sensing materials in previous reports [41,42,43,44,45,46].

Author Contributions

Conceptualization, D.Z., Z.Q. and C.L.; Data curation, C.L.; Formal analysis, R.X.; Funding acquisition, Y.Z.; Investigation, D.Z. and Z.Q.; Methodology, D.Z. and Z.Q.; Project administration, H.W.; Software, X.R.; Supervision, H.W. and Y.Z.; Visualization, R.X.; Writing—original draft, D.Z.; Writing—review and editing, Y.Z. All authors have read and agreed to the published version of the manuscript.

Funding

The authors appreciate the support of the National Natural Science Foundation of China (No. 22264025), the Applied Basic Research Foundation of Yunnan Province (No. 202401AS070033), the National Key R&D Program of China (No. 2024YFD1700200), the Yunnan Provincial Department of Education Scientific Research Fund (No. 2025Y0299), and the Reserve talents for young and middle-aged academic and technical leaders project of Yunnan Province (No. 202405AC350071, Yong Zhang).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data will be made available upon request.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Shang, Z.; Yu, X.; Ren, L.; Li, Z.; Wang, H.; Li, Y.; Wang, Y. Synergic effect of hydrogen and n-butanol on combustion and emission characteristics of a hydrogen direct injection SI engine fueled with n-butanol/gasoline. Int. J. Hydrogen Energy 2024, 49, 945–956. [Google Scholar] [CrossRef]
  2. Zhong, W.; Dai, L.; He, Z.; Wang, Q. Numerical study on the combustion characteristics of premixed ammonia flames with methanol/ethanol/n-butanol addition. Fuel 2025, 381, 133527. [Google Scholar] [CrossRef]
  3. Zhao, Z.; Su, Z.; Wu, L. Enhanced n-butanol gas sensors based on ZnO/CuCo2O4 heterojunction: Materials synthesis, sensing performance, and mechanism study. J. Alloys Compd. 2025, 1030, 180962. [Google Scholar] [CrossRef]
  4. Chen, Y.; Luo, Q.; Wan, Y.; Gao, S.; Wang, Y.; Feng, C. High-performance and rapid-response n-butanol sensor based on ZnO/SnO2 heterojunction. J. Taiwan Inst. Chem. Eng. 2025, 170, 106027. [Google Scholar] [CrossRef]
  5. Cheng, L.; Yuan, Z.; Wu, R.; Li, Z.; Zheng, J.; Song, J. A leapfrog improvement in N-butanol detection achieved through single atom catalysts Co-N-C. Chem. Eng. J. 2025, 519, 164855. [Google Scholar] [CrossRef]
  6. Hu, X.; Zhang, K.; Li, R.; Cao, Y.; Tian, D.; Zhu, Z. Synergistic CdS/Ti3C2Tx MXene heterojunction for ultrasensitive and selective n-butanol detection prepared by facile hydrothermal strategy and improved by machine learning. Chem. Eng. J. 2025, 519, 165401. [Google Scholar] [CrossRef]
  7. Chu, J.; Deng, Z.; Pan, J.; Yang, A.; Wang, Q.; Yuan, H.; Yuan, H.; Xin, F.; Rong, M.; Wang, X. Parameter Optimization of Semiconductor Gas Sensor under AC Impedance Measurement. ACS Sens. 2024, 9, 5561–5569. [Google Scholar] [CrossRef] [PubMed]
  8. Wu, Z.; Wang, C.; Liu, X.; Tan, K.; Fu, Z.; Teat, S.J.; Li, Z.W.; Hei, X.; Huang, X.; Xu, G.; et al. Confinement of 1D Chain and 2D Layered CuI Modules in K-INA-R Frameworks via Coordination Assembly: Structure Regulation and Semiconductivity Tuning. J. Am. Chem. Soc. 2023, 145, 19293–19302. [Google Scholar] [CrossRef]
  9. Wang, H.; Zhao, Y.; Yuan, Z.; Ji, H.; Meng, F. Multiscale Bidirectional Temporal Convolutional Framework for Industrial Ketone Organic Solvent Detection Based on Semiconductor Gas Sensor. IEEE Trans. Ind. Electron. 2024, 71, 16772–16782. [Google Scholar] [CrossRef]
  10. Humayun, M.; Bououdina, M.; Usman, M.; Khan, A.; Luo, W.; Wang, C. Designing State-of-the-Art Gas Sensors: From Fundamentals to Applications. Chem. Rec. 2024, 24, e202300350. [Google Scholar] [CrossRef] [PubMed]
  11. Yang, Y.; Mao, J.; Yin, D.; Zhang, T.; Liu, C.; Hao, W.; Wang, Y.; Hao, J. Synergy of S-vacancy and heterostructure in BiOCl/Bi2S3−x boosting room-temperature NO2 sensing. J. Hazard. Mater. 2023, 455, 131591. [Google Scholar] [CrossRef]
  12. Zhang, W.; Yuan, Z.; Zhu, H.; Zhang, S.; Meng, F. Kinetic Modeling in Temperature-Modulated Semiconductor Gas Sensor Utilizing Eley–Rideal Mechanism and Its Application in Discriminative Detection of VOCs. ACS Sens. 2024, 9, 6460–6470. [Google Scholar] [CrossRef]
  13. Kou, Y.; Hua, L.; Chen, W.; Xu, X.; Song, L.; Yu, S.; Lu, Z. Material design and application progress of flexible chemiresistive gas sensors. J. Mater. Chem. A 2024, 12, 21583–21604. [Google Scholar] [CrossRef]
  14. Hu, C.; Feng, Y.; Huo, J.; Zhang, B.; Cui, H.; Wang, S.; Song, Q.; Cao, J.; Dong, X. Regulating microscopic surfaces and structures to boost n-butanol sensing performances in NiCo2O4/NiO composites. Sens. Actuators B Chem. 2025, 429, 137341. [Google Scholar] [CrossRef]
  15. Jiang, B.; Cao, J.; Zhang, K.; Chen, Q.; Ma, P. Modulation of ZnFe2O4 material growth using NiO nanoparticles for highly sensitive response to n-butanol. Sens. Actuators B Chem. 2025, 430, 137321. [Google Scholar] [CrossRef]
  16. Zhou, P.; Tsang, J.; Blackman, C.; Shen, Y.; Liang, J.; Covington, J.A.; Saffell, J.; Danesh, E. A Novel Mechanism Based on Oxygen Vacancies to Describe Isobutylene and Ammonia Sensing of p-Type Cr2O3 and Ti-Doped Cr2O3 Thin Films. Chemosensors 2024, 12, 218. [Google Scholar] [CrossRef]
  17. Wang, G.; Chen, T.; Guo, L.; Wang, H.; Wang, X.; Zeng, H.; Feng, Y.; Zhao, W.; Wang, Y.; Liu, X.; et al. Chemiresistive n-butanol gas sensors based on Co3O4@ZnO hollow-sphere-array thin films prepared by template-assisted magnetron sputtering. Sens. Actuators B Chem. 2024, 413, 135862. [Google Scholar] [CrossRef]
  18. Zheng, Z.; Liu, K.; Zhou, Y.; Zhang, Z.; Su, H.; Nie, X.; Debliquy, M.; Yu, Z.; Zhang, C. Spinel type MCo2O4 (M = Mn, Mg, Ni, Cu, Fe and Zn) for chemoresistance gas sensors. Mater. Today Chem. 2024, 36, 101928. [Google Scholar] [CrossRef]
  19. Zang, D.; Wei, X.; Liu, Q.; Li, Y.; You, R. In-situ growth of ZnO@ZnWO4 heterojunction with flower-like structure by chemical vapor deposition for H2S gas sensor. Appl. Surf. Sci. 2025, 679, 161149. [Google Scholar] [CrossRef]
  20. Chen, X.; Wang, T.; Shi, J.; Lv, W.; Han, Y.; Zeng, M.; Yang, J.; Hu, N.; Su, Y.; Wei, H.; et al. A Novel Artificial Neuron-Like Gas Sensor Constructed from CuS Quantum Dots/Bi2S3 Nanosheets. Nano-Micro Lett. 2021, 14, 8. [Google Scholar] [CrossRef] [PubMed]
  21. Kim, J.; Mirzaei, A.; Zheng, Y.; Lee, J.; Kim, J.; Kim, H.W.; Kim, S.S. Enhancement of H2S sensing performance of p-CuO nanofibers by loading p-reduced graphene oxide nanosheets. Sens. Actuators B Chem. 2019, 281, 453–461. [Google Scholar] [CrossRef]
  22. Huang, C.; He, X.; Dai, T. Realization of a self-powered Cu2O ozone gas sensor through the lateral photovoltaic effect. J. Mater. Chem. C 2022, 10, 16517–16523. [Google Scholar] [CrossRef]
  23. Ren, W.; Luan, J.; Yin, L.; Xu, R.; Wang, C.; Zhang, P.; Cui, G.; Yang, K. Ultrasensitive room-temperature NO2 gas sensor based on graphene-modified Cu2O nanocomposites: A combined experimental and first-principles study. Measurement 2025, 245, 116647. [Google Scholar] [CrossRef]
  24. Tan, C.; Hsu, S.; Ke, W.; Chen, L.; Huang, M.H. Facet-Dependent Electrical Conductivity Properties of Cu2O Crystals. Nano Lett. 2015, 15, 2155–2160. [Google Scholar] [CrossRef] [PubMed]
  25. Azmoodeh, Z.; Nasirian, S.; Milani Moghaddam, H. Improving H2 gas sensing with ZnMn2O4/Polypyrrole Nanocomposite. Int. J. Hydrogen Energy 2024, 85, 854–864. [Google Scholar] [CrossRef]
  26. Cho, D.; Lee, G.; Lee, Y.; Cho, A.; Lee, S.; Kim, G.H.; Park, G.; Jang, S.; Choi, M.; Shim, Y.; et al. Ultrathin Copper Monosulfide Films for an Optically Semitransparent, Highly Selective Ammonia Chemosensor. ACS Appl. Mater. Interfaces 2024, 16, 60530–60540. [Google Scholar] [CrossRef]
  27. Li, Z.; Liu, X.; Li, S.; Feng, E.; Wu, Z.; Yang, Z.; Ma, X.; Han, X. Shape-controlled hollow Cu2O@CuS nanocubes with enhanced photocatalytic activities towards degradation of tetracycline. Environ. Technol. 2023, 44, 2702–2712. [Google Scholar] [CrossRef]
  28. Pan, L.; Dai, L.; Burton, O.J.; Chen, L.; Andrei, V.; Zhang, Y.; Ren, D.; Cheng, J.; Wu, L.; Frohna, K.; et al. High carrier mobility along the [111] orientation in Cu2O photoelectrodes. Nature 2024, 628, 765–770. [Google Scholar] [CrossRef]
  29. Frankcombe, T.J.; Liu, Y. Interpretation of Oxygen 1s X-ray Photoelectron Spectroscopy of ZnO. Chem. Mater. 2023, 35, 5468–5474. [Google Scholar] [CrossRef]
  30. Idriss, H. On the wrong assignment of the XPS O1s signal at 531–532 eV attributed to oxygen vacancies in photo- and electro-catalysts for water splitting and other materials applications. Surf. Sci. 2021, 712, 121894. [Google Scholar] [CrossRef]
  31. Dai, W.; Wan, K.; Pang, K.; Guo, J.; Liu, S.; Wu, K.; Tang, C.; Sun, Y.; Shi, X.; Tang, Z.; et al. In-depth understanding and precise modulation of surface reconstruction during heterogeneous electrocatalysis: From model to practical catalyst. Chem 2025, 11, 102345. [Google Scholar] [CrossRef]
  32. Yu, Z.; Li, F.; Di, H.; Pan, Y.; Lv, L.; Ma, Y.; Chen, Q. A facile one-pot method for preparation of the rGO–CuS/Cu2S with enhanced photocatalytic activity under visible light irradiation. J. Mater. Sci. Mater. Electron. 2016, 27, 5136–5144. [Google Scholar] [CrossRef]
  33. Hung, C.M.; Le, D.T.T.; Van Hieu, N. On-chip growth of semiconductor metal oxide nanowires for gas sensors: A review. J. Sci. Adv. Mater. Devices 2017, 2, 263–285. [Google Scholar] [CrossRef]
  34. Teterycz, H.; Halek, P.; Wiśniewski, K.; Halek, G.; Koźlecki, T.; Polowczyk, I. Oxidation of Hydrocarbons on the Surface of Tin Dioxide Chemical Sensors. Sensors 2011, 11, 4425–4437. [Google Scholar] [CrossRef] [PubMed]
  35. Li, W.; Lefferts, M.J.; Wang, Y.; Lister, A.M.; Forssberg, A.; Chen, R.; Wang, L.; Castell, M.R. Chemiresistive Polymer Percolation Network Gas Sensor Created with a Nanosphere Template. Adv. Mater. Interfaces 2023, 10, 2202042. [Google Scholar] [CrossRef]
  36. Mallik, M.; Monia, S.; Gupta, M.; Ghosh, A.; Toppo, M.P.; Roy, H. Synthesis and characterization of Cu2O nanoparticles. J. Alloys Compd. 2020, 829, 154623. [Google Scholar] [CrossRef]
  37. Wu, H.; Zhou, Y.; Guo, J.; Zhao, L.; Wang, T.; Yan, X.; Wang, C.; Liu, F.; Sun, P.; Lu, G. Highly sensitive and selective xylene sensor based on p-p heterojunctions composites derived from off-stoichiometric cobalt tungstate. Sens. Actuators B Chem. 2022, 351, 130973. [Google Scholar] [CrossRef]
  38. Yamazoe, N.; Fuchigami, J.; Kishikawa, M.; Seiyama, T. Interactions of tin oxide surface with O2, H2O and H2. Surf. Sci. 1979, 86, 335–344. [Google Scholar] [CrossRef]
  39. Zhu, Y.; Meng, X.; Wang, X.; Gao, W. Low detection based on Pd Pt /In2O3 nanospheres for rapid hydrogen detection. Sens. Actuators B Chem. 2024, 410, 135654. [Google Scholar] [CrossRef]
  40. An, D.; Liu, N.; Zhang, H.; Sun, Q.; Li, C.; Li, Y.; Zhang, Q.; Lu, Y. Enhanced n-butanol sensing performance of SnO2-based gas sensors by doping In2O3 via co-precipitation method. Sens. Actuators B Chem. 2021, 340, 129944. [Google Scholar] [CrossRef]
  41. Guo, W.; Shuai, Y.; Liu, X.; Zhang, J.; Wang, J.; Mahmoud, K.H.; El-Bahy, Z.M.; Mubarak, N.M. A n-butanol gas sensor with enhanced gas sensing performance based on Co-doped BiVO4 polyhedrons. Sens. Actuators B Chem. 2022, 354, 131221. [Google Scholar] [CrossRef]
  42. Wang, C.; Zhang, B.; Zhao, Z.; Zhang, Z.; Zhang, S.; Bala, H.; Zhang, Z. Enhanced n-butanol sensing properties of Au modified TiO2 nanorod arrays: A combined experimental and first-principle study. Appl. Surf. Sci. 2023, 641, 158458. [Google Scholar] [CrossRef]
  43. Wang, B.; Wang, Z.; Wan, Y.; Wang, Y.; Gao, S.; Chen, Y.; Luo, Q.; Feng, C. Novel Bi-doped ZnFe2O4 nanofibers based gas sensor for enhanced n-butanol sensing. J. Taiwan Inst. Chem. Eng. 2024, 157, 105395. [Google Scholar] [CrossRef]
  44. Pan, H.; Li, Z.; Lou, C.; Lei, G.; Xie, J.; Zheng, W.; Liu, X.; Zhang, J. Anchoring Fe2O3 nanosheets on NiO nanoprisms to regulate the electronic properties for improved n-butanol detection. Sens. Actuators B Chem. 2022, 354, 131223. [Google Scholar] [CrossRef]
  45. Qian, X.; Chen, Y.; Tao, Y.; Zhang, J.; Zhang, G.; Xu, H. Facile synthesis of NiFe2O4-based nanoblocks for low-temperature detection of trace n-butanol. RSC Adv. 2024, 14, 2214–2225. [Google Scholar] [CrossRef]
  46. Lv, L.; Cheng, P.; Wang, Y.; Xu, L.; Zhang, B.; Lv, C.; Ma, J.; Zhang, Y. Sb-doped three-dimensional ZnFe2O4 macroporous spheres for N-butanol chemiresistive gas sensors. Sens. Actuators B Chem. 2020, 320, 128384. [Google Scholar] [CrossRef]
Chemosensors 13 00324 g001
Figure 1. (a) XRD patterns of Cu2O and Cu2O@CuS. SEM images of (b) Cu2O and (c,d) Cu2O@CuS. (e) TEM image of Cu2O@CuS. (f) EDS images of Cu2O@CuS.
Figure 1. (a) XRD patterns of Cu2O and Cu2O@CuS. SEM images of (b) Cu2O and (c,d) Cu2O@CuS. (e) TEM image of Cu2O@CuS. (f) EDS images of Cu2O@CuS.
Chemosensors 13 00324 g001
Chemosensors 13 00324 g002
Figure 2. (a) XPS survey scans, (b) Cu 2p spectra, and (c) O 1s spectra of Cu2O and Cu2O@CuS. (d) S 2p spectrum, (e) pore size distribution and cumulative pore volume, and (f) N2 adsorption/desorption isotherms of Cu2O@CuS.
Figure 2. (a) XPS survey scans, (b) Cu 2p spectra, and (c) O 1s spectra of Cu2O and Cu2O@CuS. (d) S 2p spectrum, (e) pore size distribution and cumulative pore volume, and (f) N2 adsorption/desorption isotherms of Cu2O@CuS.
Chemosensors 13 00324 g002
Chemosensors 13 00324 g003
Figure 3. (a) Responses of different sensors to 100 ppm n-butanol measured at different operating temperatures. (b) Dynamic response curve of the hollow Cu2O@CuS nanocube-based sensor obtained by varying the n-butanol concentration at 260 °C. (c) Resistance response of the hollow Cu2O@CuS nanocube-based sensor at different n-butanol concentrations at 260 °C. (d) Cyclic repeatability of the hollow Cu2O@CuS-based sensor at 260 °C. (e) Dynamic and (f) resistive response curves of the Cu2O-based sensor at different n-butanol concentrations at 260 °C. (g) Response–recovery curve of the Cu2O@CuS-based sensor at 260 °C. (h) Long-term response stability of the Cu2O@CuS-based sensor to 100 ppm n-butanol over 45 d at 260 °C. (i) Selectivity of the hollow Cu2O@CuS nanocube-based sensor toward different VOCs at a concentration of 100 ppm at 260 °C.
Figure 3. (a) Responses of different sensors to 100 ppm n-butanol measured at different operating temperatures. (b) Dynamic response curve of the hollow Cu2O@CuS nanocube-based sensor obtained by varying the n-butanol concentration at 260 °C. (c) Resistance response of the hollow Cu2O@CuS nanocube-based sensor at different n-butanol concentrations at 260 °C. (d) Cyclic repeatability of the hollow Cu2O@CuS-based sensor at 260 °C. (e) Dynamic and (f) resistive response curves of the Cu2O-based sensor at different n-butanol concentrations at 260 °C. (g) Response–recovery curve of the Cu2O@CuS-based sensor at 260 °C. (h) Long-term response stability of the Cu2O@CuS-based sensor to 100 ppm n-butanol over 45 d at 260 °C. (i) Selectivity of the hollow Cu2O@CuS nanocube-based sensor toward different VOCs at a concentration of 100 ppm at 260 °C.
Chemosensors 13 00324 g003
Chemosensors 13 00324 g004
Figure 4. (a) Effect of the concentration of n-butanol on the response of the hollow Cu2O@CuS nanocube-based gas sensor at 260 °C. The straight solid line represents the line of best fit. (b) Effect of different relative humidity (at ambient temperature 25 °C) on the response of the sensor to 100 ppm n-butanol at 260 °C. The solid line has been added to serve as a visual guide.
Figure 4. (a) Effect of the concentration of n-butanol on the response of the hollow Cu2O@CuS nanocube-based gas sensor at 260 °C. The straight solid line represents the line of best fit. (b) Effect of different relative humidity (at ambient temperature 25 °C) on the response of the sensor to 100 ppm n-butanol at 260 °C. The solid line has been added to serve as a visual guide.
Chemosensors 13 00324 g004
Chemosensors 13 00324 g005
Figure 5. Schematic showing the sensing mechanism of the hollow Cu2O@CuS nanocube-based gas sensor in air and n-butanol gas.
Figure 5. Schematic showing the sensing mechanism of the hollow Cu2O@CuS nanocube-based gas sensor in air and n-butanol gas.
Chemosensors 13 00324 g005
Table 1. Gas source liquids and gas purity.
Table 1. Gas source liquids and gas purity.
CH3CH2OHNH3HCHOC4H10OC3H6OC7H8CO
Sourceliquidliquidliquidliquidliquidliquidgas cylinder
PurityAR25%37%ARARAR99.9%
Table 2. Different oxygen, Cu (II), and Cu (I) contents in the prepared samples.
Table 2. Different oxygen, Cu (II), and Cu (I) contents in the prepared samples.
MaterialsLattice OxygenVacant OxygenAdsorbed OxygenCu (I)Cu (II)
Cu2O59.3431.39.3647.2442.31
Cu2O@CuS35.8643.4820.6656.2933.73
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Zhang, D.; Qu, Z.; Li, C.; Wang, H.; Zhang, Y.; Ren, X.; Xu, R. Oxygen Vacancy-Engineered Cu2O@CuS p–p Heterojunction Gas Sensor for Highly Sensitive n-Butanol Detection. Chemosensors 2025, 13, 324. https://doi.org/10.3390/chemosensors13090324

AMA Style

Zhang D, Qu Z, Li C, Wang H, Zhang Y, Ren X, Xu R. Oxygen Vacancy-Engineered Cu2O@CuS p–p Heterojunction Gas Sensor for Highly Sensitive n-Butanol Detection. Chemosensors. 2025; 13(9):324. https://doi.org/10.3390/chemosensors13090324

Chicago/Turabian Style

Zhang, Di, Zhengfang Qu, Chenchen Li, Huan Wang, Yong Zhang, Xiang Ren, and Rui Xu. 2025. "Oxygen Vacancy-Engineered Cu2O@CuS p–p Heterojunction Gas Sensor for Highly Sensitive n-Butanol Detection" Chemosensors 13, no. 9: 324. https://doi.org/10.3390/chemosensors13090324

APA Style

Zhang, D., Qu, Z., Li, C., Wang, H., Zhang, Y., Ren, X., & Xu, R. (2025). Oxygen Vacancy-Engineered Cu2O@CuS p–p Heterojunction Gas Sensor for Highly Sensitive n-Butanol Detection. Chemosensors, 13(9), 324. https://doi.org/10.3390/chemosensors13090324

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop