SnO₂/graphitic carbon nitride (g-C₃N₄) composites were synthesized via a facile solid-state method by using SnCl₄·5H₂O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), thermogravimetry-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), and N₂ sorption. The results indicated that the composites possessed a two-dimensional (2-D) structure, and the SnO₂ nanoparticles were highly dispersed on the surface of the g-C₃N₄ nanosheets. The gas-sensing performance of the samples to ethanol was tested, and the SnO₂/g-C₃N₄ nanocomposite-based sensor exhibited admirable properties. The response value (Ra/Rg) of the SnO₂/g-C₃N₄ nanocomposite with 10 wt % 2-D g-C₃N₄ content-based sensor to 500 ppm of ethanol was 550 at 300 °C. However, the response value of pure SnO₂ was only 320. The high surface area of SnO₂/g-C₃N₄-10 (140 m²·g⁻¹) and the interaction between 2-D g-C₃N₄ and SnO₂ could strongly affect the gas-sensing property.

The SnO₂/g-C₃N₄ composites were synthesized via a facile calcination method by using SnCl₄·5H₂O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), the field-emission scanning electron microscopy and transmission electron microscopy (FESEM and TEM), energy dispersive spectrometry (EDS), thermal gravity and differential thermal analysis (TG-DTA), and N₂-sorption. The analysis results indicated that the as-synthesized samples possess the two dimensional structure. Additionally, the SnO₂ nanoparticles were highly dispersed on the surface of the g-C₃N₄ nanosheets. The gas-sensing performance of the as-synthesized composites for different gases was tested. Moreover, the composite with 7 wt % g-C₃N₄ content (SnO₂/g-C₃N₄-7) exhibits an admirable gas-sensing property to ethanol, which possesses a higher response and better selectivity than that of the pure SnO2-based sensor. The high surface area of the SnO2/g-C3N4 composite and the good electronic characteristics of the two dimensional graphitic carbon nitride are in favor of the elevated gas-sensing property.

In this study, α-Fe₂O₃@g-C₃N₄ photocatalyst was synthesized using an ultrasonic assisted self-assembly preparation method. The α-Fe₂O₃@g-C₃N₄ photocatalyst had a stronger optical absorption in the visible light region than pure graphitic carbon nitride (g-C₃N₄). The Z-Scheme heterojunction between α-Fe₂O₃ and g-C₃N₄ significantly inhibited the recombination of electrons and holes. The photocatalytic performances of α-Fe₂O₃@g-C₃N₄ photocatalyst were excellent in degradation of Rhodamine B (RhB) under visible light irradiation. The results indicated that 5 wt.% α-Fe₂O₃/g-C₃N₄ had the optimal photocatalytic activity because two-dimension (2D) α-Fe₂O₃ nanosheets can be well-dispersed on the surface of g-C₃N₄ layers by ultrasonic assisted treatment. A possible photocatalytic mechanism is also discussed.

Developing an efficient non-noble catalyst for CO oxidation with high catalytic activity remains a challenge for practical applications. In this work, CuO nanorods decorated reduced graphene oxide (RGO) nanocatalysts were prepared via a facile one-step hydrothermal method. The structure and morphology of the as-prepared samples were characterized by XRD, Raman spectroscopy, SEM, TEM, and X-ray photoelectron spectroscopy (XPS). The analysis results show that CuO nanorods were successfully deposited on the surface of RGO sheets with the length of 250–500 nm. The catalytic properties of the as-prepared catalysts for CO oxidation were evaluated by using a microreactor-gas chromatograph (GC) system. The as-prepared RGO–CuO nanocatalysts exhibited high activity for CO oxidation, and the 10 wt % reduced graphene oxide content catalyst can achieve CO total oxidation at 165 °C.

Pd nanoparticles (PdNPs) stabilized by methyl cellulose (MC) were synthesized in an aqueous solution, which are monodispersed nanoparticles. PdNPs/α-Al₂O₃ catalyst was prepared with monodispersed PdNPs and showed better catalytic performance than Pd/α-Al₂O₃ catalyst prepared by the incipient wetness impregnation method using Pd(NO₃)₂ as a precursor. The catalysts were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS). It was found that monodispersed PdNPs were spherical or elliptical nanoparticles with exposed (111) and (100) facets, and the PdNPs/α-Al₂O₃ catalyst showed a more concentrated distribution of Pd particles on the surface of α-Al₂O₃ support than the Pd/α-Al₂O₃ catalyst. The preparation method achieved the highly dispersed PdNPs/α-Al₂O₃ catalyst with smaller Pd particle size and decreased the aggregation of Pd active sites, which was responsible for higher acetylene conversion and ethylene selectivity.