Calcination Treatment Research Articles

Synergistic removal of tetracycline hydrochloride by nano-MnOx/NCF composite fiber (MNCs) catalysts via heterogeneous peroxymonosulfate (PMS) activation

Nnano-MnOx/NC composite fibers (MNCs) has been successfully prepared by the calcination treatment of Mn-Nitrilotriacetic acid (Mn-NTA) fibers precursor that are synthesized by hydrothermal method. The in-situ formed nano-MnOx is adhered to the N doped carbon nanofibers. The as-prepared MNCs fibers are employed as catalyst to decompose tetracyclines hydrochloride (TCH) by activating peroxymonosulfate. Compared with other MNCs catalyst, the synergistic effect of Mn3O4 and N-doping carbon in MNC-700 during the catalytic process endows MNC/PMS system with the superior mineralization capacity for TCH degradation with less amount of catalyst and PMS. Quenching experiments and EPR tests confirm that the oxidative degradation of TCH involves radical and non-radical route. Multiple reactive oxygen species (SO4−, OH, and 1O2) contribute to the degradation of TCH. Our research offers an effective strategy for the TCH degradation through PMS activation using the composite fibers of MnOx and N doped carbon.

Target-oriented element activation and functional group synthesis lead to high quality modified clay for Prorocentrum donghaiense control

Single source with series modifications (SSSM) is a new method to modify clay surfaces by activating clay mineral resources for harmful algal blooms control. In this study, the optimal preparation conditions for this method were obtained using response surface methodology. Based on the material analysis, an important way to obtain modified clay (MC) with the excellent Prorocentrum donghaiense removal performance was explored and the optimum preparation conditions were as follows: calcination temperature 750°C, alkali neutralization pH 3.7 and clay supplementation ratio 1.3:1. Under these conditions, the calcination treatment can effectively activate the aluminum element in the clay lattice and obtain the largest amount of highly active Al IV and Al V, which are readily released from the lattice as activated aluminum. When the alkali neutralization pH was adjusted to 3.7, the activated aluminum was hydrolyzed and induced into highly positively charged polyhydroxyaluminum compounds. The supplemented kaolin increased the yield of the MC product by surface convergence of the activated aluminum in the system. As a result, the optimized MC can form large particle size flocs with good regeneration and stability during the algal removal process, which greatly improved its ability to coagulate and sediment algal cells. Overall, the MC prepared by the SSSM method achieved high algal removal efficiency through targeted element activation and functional group shaping.

Green synthesis of Zeolite@Ag/TiO2 heterostructure for the enhanced Cd2+ adsorption from aqueous solution

A simple approach has been developed to synthesize zeolite-based Ag-doped TiO2 (Z@Ag/TiO2) heterostructure using impregnation processes followed by calcination treatments e. g. 500, and 700 °C. The nanocomposite heterostructure was characterized via XRD, EDX, XRF, FTIR, and UV–Vis DRS techniques, and the surface charge analysis was carried out using the pH drift method. The ability of the prepared materials was tested for the adsorption of Cd2+ ions from solution under normal conditions of pH, temperature, and visible light (compact fluorescent light, CFL). The characterization results revealed that the support materials significantly alter the optical (i.e. reduction in bandgap energy, from 3.20 to 2.92 eV), and surface charge (i.e. pHPZC, from 6.6 to 7.6) properties of the TiO2 nanoparticles (NPs). The prepared Z@Ag/TiO2 materials exhibited maximum removal efficiencies (∼168 mg/L) for the removal of Cd2+ as compared to pure TiO2 (∼68 mg/L), from single solution. A further significant enhancement in the Cd2+ removal efficiency (99 %, removal = 198 mg/L) was observed in the presence of photo-generated positive hole scavenger, e. g. organic additive methylene blue (MB). The high-temperature regenerated samples showed more regeneration efficiency as compared to Fenton regeneration. Meanwhile, the re-utilization study of the easily separable heterostructure revealed a gradual decrease of 8–15 % after three cycles compared to the fresh sample. The desorption study indicated negligible desorption (0.3 %) from the freshly used sample which reached ∼ 2.3 % from the four times used samples. The easy separation, lessor desorption, and re-utilization of the Z@Ag/TiO2 composite show the effectiveness of the prepared materials for Cd2+ ions removal.

Insights into the oxygen vacancies in titanium-aluminum composite oxides for Ru-catalyzed bio-oil upgrading using guaiacol as a model compound

The high quality liquid products obtained from upgrading of bio-oil through hydrogenation can serve as viable alternatives to fossil fuels, thereby alleviating the strain on energy supply. In this study, a series of titanium-aluminum composite oxides (TixAlyO) was prepared by a sol-gel method and used as supports to fabricate ruthenium (Ru)-based catalysts for the hydrogenolysis upgrading of bio-oil. Various techniques, including in situ pyridine adsorption-Fourier-transform infrared spectroscopy (in situ Py-FTIR), in situ CO diffuse-reflectance Fourier-transform infrared spectroscopy (in situ CO DRIFTS), and CO2 temperature-programmed desorption (CO2-TPD), were employed to characterize the physicochemical and electronic structures of the catalysts. Using guaiacol as a model compound for bio-oil, the compositions and structures of the TixAlyO supports, as well as the effect of calcination treatment of the supports in an N2 atmosphere, on the hydrogenolysis reactivity, were investigated in detail. The results indicated that the hydrogenolysis rate of Caromatic−O bonds showed a significant linear correlation with the oxygen vacancy/Lewis acid content. Furthermore, the presence of oxygen vacancies facilitated the formation of small Ru nanoparticles. Importantly, calcination of the support in an N2 atmosphere facilitated the formation of metal/oxide interface sites in the Ru/Ti5Al5O-N catalyst, further augmenting its Lewis acidity and reducing the activation energy for the hydrogenolysis of the Caromatic−O bonds. The hydrogenolysis rate of the Caromatic−O bond in guaiacol over the oxygen vacancy-rich catalyst Ru/Ti5Al5O-N was increased by a factor of 2–4 compared to those over Ru-based catalysts with a single oxide support. This study exemplified a novel strategy of oxygen vacancy-promoted hydrogenolysis upgrading of bio-oil.

Aluminium-doped vanadium nitride as cathode material for high-performance aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are increasingly favored for their environmentally friendly and impressive energy storage performance. Vanadium nitride (VN) is receiving much attention as a cathode material for AZIBs due to its high electrical conductivity and controllable structure. However, the direct use of VN in AZIBs presents challenges such as sluggish kinetics, insufficient specific capacity and limited stability. Herein, a heteroatom doping strategy is utilized to improve the electrochemical energy storage performance of the VN by incorporating aluminium (Al) via a hydrothermal process and a subsequent calcination treatment. Electrochemical characterizations indicate that the as-synthesized aluminium-doped VN (Al-doped VN) exhibits an outstanding specific capacity of 544 mAh·g−1 at 1 A g−1 and retains a high rate capacity of 275.6 mAh·g−1 at 10 A g−1. Further studies show that the Al incorporation effectively modulates the electronic configuration of the VN, which accelerates the charge transfer kinetics and thus enhances the electrochemical storage performance of VN. The phase transformation mechanism of the Al-doped VN is also investigated and the results show that the VN undergoes partial conversion into Zn3(OH)2V2O7·2H2O during the charge/discharge process.

Activation of periodate by CNT for selective catalytic oxidation: The overlooked significant role of residual metal species as catalytic sites

Carbon nanotubes (CNTs) catalyzed activation of peroxides has been extensively investigated, while the role of residual metal species in CNT in the catalysis is largely overlooked. In the study, calcination treatment of pristine CNT at high temperatures was employed as an approach to gain an insight into the role of residual metal species as catalytic sites in promoted catalytic activation of periodate (PI). Firstly, the calcination treatment at 500–1100 °C significantly promoted PI activation by calcined CNT. By constructing the quantitative structure–activity relationships (QSARs) between several surface and bulk properties of CNT (such as total surface oxygen content, surface carbonyl group, bulk defect and residual metal species) and PI activation performance, the residual metal species were identified as the catalytic sites. Moreover, the purification method of pristine CNT in the concentrated HNO3 was confirmed to be not efficient to remove these residual metals. The calcination treatment can tune the electronic structure of residual metal species, and promote their exposure and electron donation capacity for PI activation, thus significantly improving PI activation performance. Moreover, IO3• was identified as the dominant reactive species in CNT/PI system via a line of approaches including quenching experiments, PI decomposition in the presence/absence of organic pollutants, electrochemical testes, high selectivity in degradation of organic pollutants, QSARs of substituted phenols, and analysis of degradation products of 4-bromophenol. Furthermore, the CNT/PI system exhibited a wide pH application range of 3–11, high anti-interference to bicarbonate, chloride and phosphate in water. The study advances the understanding on the residual metal species in CNT and its overlooked catalytic role in PI activation, and also provides a high-performance oxidation process for wastewater purification.

Interface and doping engineering of V2C‐MXene‐based electrocatalysts for enhanced electrocatalysis of overall water splitting

AbstractThe restacking and oxidizable nature of vanadium‐based carbon/nitride (V2C‐MXene) poses a significant challenge. Herein, tellurium (Te)‐doped V2C/V2O3 electrocatalyst is constructed via mild H2O2 oxidation and calcination treatments. Especially, this work rationally exploits the inherent easy oxidation characteristic associated with MXene to alter the interfacial information, thereby obtaining stable self‐generated vanadium‐based heterointerfaces. Meanwhile, the microetching effect of H2O2 creates numerous pores to address the restacking issues. Besides, Te element doping settles the issue of awkward levels of absorption/desorption ability of intermediates. The electrocatalyst obtains an unparalleled hydrogen evolution reaction and oxygen evolution reaction with the overpotential of 83.5 and 279.8 mV at −10 and 10 mA cm−2, respectively. In addition, the overall water‐splitting device demonstrates a low cell voltage of 1.41 V to obtain 10 mA cm−2. Overall, the inherent drawbacks of MXene can be turned into benefits based on the planning strategy to create these electrocatalysts with desirable reaction kinetics.

Facile boosting catalytic thermal decomposition of ammonium perchlorate from 3D porous nano Co3O4@ZnO composites

The design of efficient catalysts for the pyrolysis of ammonium perchlorate (AP) is important for the performance of composite solid propellants. Co3O4@ZnO heterojunction composites were fabricated by hydrothermal and calcination treatments and used to promote the thermal decomposition of AP. The influences of the Co/Zn molar ratio on the catalytic performance and the content of decomposition products of AP were investigated by various techniques such as TEM, XPS, BET, EIS, and TG-IR. The results revealed that the Co/Zn = 3 sample exhibited excellent performance with the high-temperature decomposition (HTD) temperature of AP reduced from 410°C to 295 °C and the apparent activation energy decreased to 98.7 kJ/mol in the case of 2 wt% addition, attributed to the construction of a heterojunction with abundant active sites enhancing the charge transfer capability between the Co3O4 and ZnO. The decomposition pathway of AP is influenced by the catalyst components, and the Co/Zn = 3 nanostructures demonstrated outstanding catalytic performance by accelerating the decomposition of HClO4 and the conversion of NH3, and promoting the production of N2O, NO, and NO2. This work provides a feasible strategy for the development of Co3O4@ZnO catalysts with excellent catalytic activity towards AP.

Characterization of SnO2-based gas sensors to analyze diesel and biodiesel blends

This study analyzed biodiesel blends using sensors constituted by SnO2 pellets with gold interdigitated contacts deposited on the surface. Tin dioxide was synthesized by the polymeric precursor method with further calcination treatment at 500°C, conformed and sintered at three temperatures to form three different samples: 700°C (Sn1), 900°C (Sn2) and 1100°C (Sn3). The samples were analyzed by X-Ray Diffraction, FEG-SEM (Field Emission Gun - Scanning Electron Microscopy), Raman spectroscopy, and electrical measurements. Results confirmed the formation of rutile-type tetragonal cassiterite phase, with quasi-spherical particles a moderate degree of heterogeneity in particle size 30-90 nm). Raman vibrational modes and infrared spectrum also confirmed the presence of tin oxide in high purity rutile phase. Sensorial measurements showed high sensitivity, response, and recovery time in tests with biodiesel/ethanol mixtures, allowing to distinguish between blends with a wide range of composition and serving as a potential device to detect adulterated fuel.

Ni doped carbon-based composites derived from waste cigarette polypropylene filter rod with electromagnetic wave absorption performance

Abstract Polypropylene is widely used in the plastics industry, especially in the tobacco industry, served as cigarette filters to reduce tar and harm. However, it’s difficult to degrade these polypropylene plastics and suitable methods for recycling and reuse is urgent. This research proposes an efficient method for the reuse of polypropylene cigarette filters by mixing waste polypropylene filters with nickel source in different proportions, followed by a facile calcination treatment to prepare nickel-modified carbon-based composite materials with excellent microwave absorption properties. Morphology and magnetic properties of as-prepared samples were analyzed via XRD, SEM, and VSM, exhibiting an increase in carbon content with raising nickel content. Nickel ion anchored on polypropylene fiber may facilitate better fixation of carbon chains during the polypropylene decomposition process. Among the as-prepared samples, CN2 exhibited superior microwave absorption performance, with an optimal absorption peak of -26.76 dB at 7.97 GHz when matched with a given thickness of 4.3 mm, and an effective absorption bandwidth of 3.64 GHz (8.04 GHz to 11.68 GHz) with a matching thickness of 3.5 mm, covering the X band. Therefore, the as-prepared microwave absorbers provides a feasible solution for the recycling and reuse of polypropylene filters, aligning with the tobacco industry requirements for green and sustainable development.

Poly(lactic acid)/poly(vinyl butyral) composites containing kaolin modified by acids and calcination

AbstractThe compatibility between two distinct polymers in the blend is important to maximize various properties of the blends. This study investigated the effects of kaolin modifications through acid and calcination treatments on the compatibility, molecular weight, its distribution, and various properties of poly(lactic acid) (PLA)/poly(vinyl butyral) (PVB) blends. In addition, the incorporation of the modified kaolin as a compatibilizer into the blends enhanced their mechanical and thermal properties, addressing the challenges of immiscibility between distinct polymers. The experimental approach included the utilization of scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, x‐ray diffraction, Fourier transform infrared spectroscopy, rheometer, and melt flow index to examine the structural, molecular, and thermal, mechanical and rheological behaviors of the composites. The changes in various molecular weights were correlated with other properties. The incorporation of surface‐treated kaolin into the blend improved the compatibility between PLA and PVB, exhibiting a singular melting temperature peak and a less distinct interface between two different polymers. This research contributed to the development of sustainable material solutions by demonstrating the potential of modified inorganic fillers in improving the performance of biodegradable polymer blends.

Zn-doped V2O5 film electrodes as cathode materials for high-performance thin-film zinc-ion batteries

Zn-doped V2O5 film electrodes were prepared by in-situ growth on indium‑tin oxide (ITO) conductive glass by a low-temperature liquid-phase deposition method and calcined by calcination treatment, and assembled into thin-film zinc-ion batteries (ZIBs). After galvanostatic charge/discharge (GCD) tests with 90 and 200 charge/discharge cycles, the ZIBs system provided specific capacities of 95.7 mAh m−2 and 63.9 mAh m−2 with capacity retention rates of 97.88% and 78.72%, respectively. The electrochemical reaction process of the Zn-doped V2O5 film electrode was analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to understand the insertion/extraction mechanism of Zn2+. The doping of appropriate amount of Zn2+ in the preparation plays the role of “pillar”, which helps to stabilize the structure of V2O5 and improve the cycling stability and lifetime. Therefore, the research may provide a new idea for the assembly and preparation of thin-film ZIBs with improved performance.

Electronic structure engineering of CNTs@NiFe-LDH composite via heteroatom doping for efficient seawater electrolysis

Exploring cost-effective, efficient, and durable bifunctional electrocatalysts for seawater splitting is crucial for green hydrogen production. Electronic structure engineering stands out as a promising method to tailor catalyst properties and enhance catalytic performance. In this work, a bifunctional composite, N-CNTs@NiFeZr-LDH, for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), is designed and fabricated. Results show that the incorporation of Zr into NiFe-LDH and N into CNTs generates a synergistic effect that optimizes the electronic structure of the composite, leading to a noticeable improvement in catalytic performance. Interestingly, a straightforward calcination treatment further enhances the catalytic performance. The optimized sample exhibits a current density of 100 mA cm−2 with ultra-low overpotentials of 210 and 185 mV for the HER and OER, respectively, in simulated seawater (1.0 M KOH + 0.5 M NaCl). When applied to overall water splitting in simulated seawater, a two-electrode electrolyzer assembled by the optimized sample achieves a current density of 350 mA cm−2 with only 1.65 V, and can operate steadily for 100 h. In natural seawater, the assembled electrolyzer delivers 350 mA cm−2 requiring only 1.68 V, together with an impressive stability. Besides offering an efficient bifunctional catalyst for seawater electrolysis, this work underscores the crucial role of electronic engineering in enhancing the intrinsic catalytic activity.

Facile and precise synthesis of core-shell ZnO/C nanorods with excellent microwave absorption

Carbonaceous materials have great prospects in microwave absorption due to their lightweight and corrosion resistance. However, their high conductivity leads to poor impedance matching, posing a significant challenge for obtaining outstanding microwave absorption (MA) materials from carbonaceous materials. In this work, the core-shell ZnO/C nanorods (ZCNs) are prepared by covering conductive carbon on the surface of ZnO nanorods through a simple stirring process in ambient temperature and calcination treatment. The thickness of carbon shell is carefully regulated to realize appropriate impedance matching and strong microwave dissipation capability. ZCN with 30.2 nm of carbon shell achieves outstanding microwave absorption in low frequency and broadband microwave absorption because of the synergies of optimized impedance matching and enhanced dielectric loss: the reflection loss of 49.9 dB at 6.32 GHz, and the effective absorption bandwidth of 6.4 GHz at a corresponding thickness of 2.0 mm. RCS simulation results have verified its excellent performance in practical application. This study proposes a simple and effective idea for the efficient utilization of carbonaceous materials in microwave absorption.

Insights into the impact of self-contained sulfur impurity on the superior photocatalytic activity of UV100

The commercial Hombikat UV100 is a TiO2 photocatalyst that is less studied and used than Aeroxide P25, resulting in limited knowledge associated to it. In this study, we used ICP-OES, XPS, and TGA analyses to show that UV100 contains non-negligible traces of sulfur as-received, which can be migrated to the surface of TiO2 through a simple calcination treatment. Ionic chromatography, DRIFTS, and pyridine-TPD analyses confirmed that a portion of the surface sulfate after the thermal induced migration can be removed by distilled water, along with associated sodium cations, without impacting the surface chemistry of the photocatalyst. Calcination of UV100 enhanced the photocatalytic activity in the liquid-phase degradation of phenol, paracetamol, and chloramphenicol, and this activity remained relatively unaffected by the leaching of sulfate. Although EPR indicated that surface-bound sulfate might act as electron trapping centers or oxygen chemisorption centers, the primary reason for the improved photocatalytic activity is likely the increased crystallinity of the anatase phase due to high-temperature calcination, aided by sulfur’s retarding effect on the anatase-to-rutile transition.

Multi-mode luminescence anti-counterfeiting and visual iron(Ⅲ) ions RTP detection constructed by assembly of CDs&Eu3+ in porous RHO zeolite

Carbon dots (CDs)-based composites have shown impressive performance in fields of information encryption and sensing, however, a great challenge is to simultaneously implement multi-mode luminescence and room-temperature phosphorescence (RTP) detection in single system due to the formidable synthesis. Herein, a multifunctional composite of Eu&CDs@pRHO has been designed by co-assembly strategy and prepared via a facile calcination and impregnation treatment. Eu&CDs@pRHO exhibits intense fluorescence (FL) and RTP coming from two individual luminous centers, Eu3+ in the free pores and CDs in the interrupted structure of RHO zeolite. Unique four-mode color outputs including pink (Eu3+, ex.254 nm), light violet (CDs, ex.365 nm), blue (CDs, 254 nm off), and green (CDs, 365 nm off) could be realized, on the basis of it, a preliminary application of advanced information encoding has been demonstrated. Given the free pores of matrix and stable RTP in water of confined CDs, a visual RTP detection of Fe3+ ions is achieved with the detection limit as low as 9.8 μmol/L. This work has opened up a new perspective for the strategic amalgamation of luminous guests with porous zeolite to construct the advanced functional materials.

MOF-Derived Zn/N-Doped Porous Carbon Film on a Carbon Nanotube for High-Performance Supercapacitors.

Designing high-performance binder-free electrochemical electrodes is crucially important toward supercapacitors. In this paper, a Zn/N-doped porous carbon film coating on flexible carbon nanotubes (ZIF-8@CT-800) derived from the epitaxial Zn-MOF film growth on cotton textile was successfully fabricated via a combination of the liquid-phase epitaxial (LPE) method and calcination treatments. The ZIF-8@CT-800 serves directly as a self-supported electrode for supercapacitors and exhibits a high areal capacitance of 930 mF·cm-2 at a current density of 1 mA·cm-2 and a good recyclability of 86% after 2000 cycles. The excellent supercapacitor property is ascribed to the unique structural design of ZIF-8@CT-800, which provides appropriate channels for enhanced electronic and ionic transport as well as increased surface area for accessing more electrolyte ions. This work will provide significant guidance for designing MOF-derived porous carbon to construct flexible binder-free electrode materials with high electrochemical performance.

Low-Temperature Catalytic Transfer Hydrogenation of Biomass-Derived Furfural over Irreversibly Adsorbed and Highly Dispersed Zr(IV) Species.

Developing pure inorganic catalysts for low-energy transfer hydrogenation of biomass-derived furfural and alcohols below 100 °C is still challenging. This work reports highly dispersed Zr(IV) species catalysts prepared by irreversible adsorption of different solvent-dissolved Zr(IV) cations such as Zr4+ or [Zr4(OH)8(H2O)16]8+ on/in SBA-15 through Zr-O coordination, without adding an alkaline precipitant and calcination treatment. In the transfer hydrogenation of furfural to furfuryl alcohol, the Zr(IV) species catalysts exhibited unexpectedly outstanding transfer hydrogenation activity at low temperatures of 70 and 85 °C, superior to other transition-metal (Zr4+, Hf4+, Fe3+, etc.)- and main-group metal (Al3+, etc.)-based inorganic catalysts, which need high reaction temperatures above 100 °C, and comparable to the best-performing metal-organic hybrid catalysts with precise defect engineering modification or specific macromolecular ligands, and had negligible Zr leaching amounts (<0.01%) in water and in the collected liquid reaction medium from 7 cycles of reactions. In addition, the large strong Lewis acidic site amount rather than the large total acidic amount is a crucial condition for the catalysts to obtain high transfer hydrogenation activity, and basic sites were also involved in catalysis, and their absence would induce the acetalization side reaction. Furthermore, the catalysts were universal for low-temperature transfer hydrogenation of other aldehydes.

Hollow engineering of Co/N-doped C@carbon aerogel with hierarchical structure boosting interfacial polarization for ultra-thin microwave absorption and thermal insulation

Rational manipulation of the composition and microstructure design of aerogel materials is considered to be an effective method for achieving the dual functions of microwave absorption and thermal insulation. Herein, hollow Co/N-doped C@carbon aerogel with hierarchical structures was designed and constructed via a synergistic strategy including directed freeze-drying, ZIF-67 in situ growth, chemical etching and calcination treatment. Co/N-doped hollow carbon nanocages derived from ZIF-67 with uniform heterojunctions and layered micro-mesopores were constructed using tannic acid and heat treatment process. After that, abundant macroporous structure from the carbon aerogel itself was further introduced to upgrade the impedance matching property, light weight and interfacial polarization loss capability. Remarkably, as-fabricated Co/N-doped C@carbon aerogel (ZTA@A-900) displays optimal MA performance with a minimum reflection loss (RLmin) value of −54.0 dB at 15.32 GHz and a broad effective absorption bandwidth (EAB) of 4.04 GHz (13.44–17.48 GHz) at a thickness of only 1.4 mm. Furthermore, the ideal CST simulation results and excellent thermal insulation property of ZTA@A-900 make it an outstanding candidate for microwave absorbers under extreme conditions. Thus, our work opens up a new avenue for the design and fabrication of multifunctional lightweight microwave absorbers.

Facile synthesis of porous Au-decorated SnO2 microflowers with abundant oxygen vacancies for trace VOCs detection

Hierarchical Au-decorated SnO2 (Au@SnO2) microflowers with a porous structure were successfully synthesized. The preparation process involves in a hydrothermal method, calcination treatment, as well as modification. The hierarchical structure consisted of a large number of porous, uniform nanosheets. Excellent gas-sensing performances were demonstrated by the gas sensors fabricated using Au@SnO2 microflowers, for detecting volatile organic compounds (VOCs). In particular, for the accurate and fast detection of formaldehyde, the 2%Au-decorated SnO2 microflowers sensors showed a strong sensing response (76.5) for formaldehyde (100 ppm) at 140 °C, approximately three times higher than that (28.2) observed for the pure porous SnO2 microflowers. The response and recovery times (10 s/16 s) were shorter than those (12 s/25 s) of the pure SnO2, respectively. The detection limit for the 2%Au@SnO2 sensor was 19.03 ppb. The sensing mechanism of Au@SnO2 sensors was also investigated. Favorable porous 3-dimensional structure, high catalytic activity, and electron sensitization effect of Au nanoparticles (NPs) improved the gas-sensing performance. Furthermore, the catalytic activity of Au NPs was maximized due to their uniform distribution on the surface of each porous SnO2 nanosheet. The Au-decorated SnO2 microflowers sensors have great potential for the accurate, fast, and highly sensitive response detection of formaldehyde gas.