A series of ZnCo2O4/rGO/Pt nanocubes with excellent photocatalytic activity towards visible light

H2S/Butane Dual Gas Sensing Based on a Hydrothermally Synthesized MXene Ti3C2Tx/NiCo2O4 Nanocomposite

Real-time sensing of hydrogen sulfide (H2S) at room temperature is important to ensure the safety of humans and the environment. Four kinds of different nanocomposites, such as MXene Ti3C2Tx, Ti3AlC2, WS2, and MoSe2/NiCo2O4, were synthesized using the hydrothermal method in this paper. Initially, the intrinsic properties of the synthesized nanocomposites were studied using different techniques. P-type butane and H2S-sensing behaviors of nanocomposites were performed and analyzed deeply. Four sensor sheets were fabricated using a spin-coating method. The gas sensor was distinctly part of the chemiresistor class. The MXene Ti3C2Tx/NiCo2O4-based gas sensor detected the highest response (16) toward 10 ppm H2S at room temperature. In comparison, the sensor detected the highest response (9.8) toward 4000 ppm butane at 90 °C compared with the other three fabricated sensors (Ti3AlC2, WS2, and MoSe2/NiCo2O4). The MXene Ti3C2Tx/NiCo2O4 sensor showed excellent responses, minimum limits of detection (0.1 ppm H2S and 5 ppm butane), long-term stability, and good reproducibility compared with the other fabricated sensors. The highest sensing properties toward H2S and butane were accredited to p-p heterojunctions, higher BET surface areas, increased oxygen species, etc. These simply synthesized nanocomposites and fabricated sensors present a novel method for tracing H2S and butane at the lowest concentration to prevent different gas-exposure-related diseases.

Hydrogen peroxide-assisted photocatalytic dye degradation over reduced graphene oxide integrated ZnCr2O4 nanoparticles

Zinc chromite nanoparticles (NPs) and zinc chromite-reduced graphene oxide (ZnCr₂O₄-rGO) nanocomposite have been synthesized by the combined effects of reflux condensation and calcination processes. The structural properties were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible studies, etc. Structural morphology was investigated by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) that indicate the formation of particles in the nanometer regime. The presence of the elements Zn, Cr, O and C has been confirmed by energy-dispersive X-ray spectroscopy (EDX) images which show the purity of the synthesized products. The photocatalytic activities of both as-prepared samples under visible light irradiation were investigated in presence of hydrogen peroxide (H₂O₂) and the results show that ZnCr₂O₄-rGO nanocomposite has a quite higher photo-activity response than virgin ZnCr₂O₄ NPs. The enhanced photo response indicates that, in ZnCr₂O₄, the photo-induced electrons favor to transfer to the rGO surface and the recombination of electron-hole pairs inhibited for which it results in the significantly increased photocatalytic activity for the ZnCr₂O₄-rGO photocatalyst and this phenomenon is also supported by the band gap value and photoluminescence results. Our outcomes demonstrate that ZnCr₂O₄-rGO nanocomposite is a more promising material to build up an efficient photocatalyst for waste water treatment.