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• A facile hydrothermal synthesis route of Ag@ZnO@rGO was developed. • The efficiency of electrochemical CO 2 reduction is highly dependent on the porosity and conductivity properties. • The effective interaction in porous material enhances high-performance CO 2 reduction. Carbon dioxide (CO 2) accounts for the most significant proportion of greenhouse gas emissions, progress towards decrease the existence of atmospheric CO 2 have received considerable attention. Therefore, focus on carbon capture and utilization, which reduces the content of CO2 and provides an excellent solution to generate value-added and renewable fuels. Herein, the electrochemical CO 2 reduction activity of Ag@ZnO@rGO electrocatalysts prepared by facile synthesis route has been systematically investigated. The good incorporation of Ag in the ZnO NPs matrix (Ag@ZnO) was synthesized through the thermal calcination of Ag+-impregnated ZIF8. Then, Ag@ZnO was coated by rGO using a hydrothermal technique. We found that the efficiency of electrochemical CO 2 reduction is highly dependent on the porosity and conductivity properties. The effective interaction of rGO in Ag-based ZnO porous nanoparticles showed high activity, leading to reach Faradaic efficiencies of about 70% at −1.6 V vs. SCE. To the best of our knowledge, the performance in this work is comparable to the literature. Additionally, the electrocatalyst stays for more than 30 min without any significant change of activity, possessing the ability for applications to reducing CO 2. [ABSTRACT FROM AUTHOR]

• Rapid adsorption of Rhodamine B (Rh.B) by ZIF-8 under visible light irradiation. • Blue-shifted π –π* transition of aromatic π system of Rh.B adsorbed on the ZIF-8. • ZIF-8 generated hydroxyl radicals for the degradation of organic dye under UV light. • Density functional theory coupled with spectroscopic techniques were optimized. The adsorption of Rhodamine B (Rh.B) was achieved by Zeolite imidazolate framework-8 (ZIF-8) in the dark condition, and the adsorption rate was noticeably increased under visible and UV light irradiations. According to fluorescence spectroscopic studies, ZIF-8 under UV light generated hydroxyl radicals for the effective degradation of Rh.B dyes. These featured mechanisms were systematically elucidated by investigating the zeta potentials of ZIF-8/Rh.B; blue-shifted π –π* transition of aromatic system; chemical shift of 13C NMR spectra; FTIR spectra; and high surface area and abundant mesopores of ZIF-8. Furthermore, the interaction mechanism between Rh.B with ZIF-8 was studied using a density functional theory (DFT) coupled with a spectroscopic technique. Herein, nine ZIF-8 clusters and Rh.B molecules were optimized in aqueous solution using the polarizable continuum model to address the solvation effect. The DFT calculations suggested that π-π stacking interactions between the xanthene ring of Rh.B and the imidazole rings of ZIF-8 and electrostatic interactions between electron-deficient Zn centers and Rh.B predominantly contributed to the adsorption of Rh.B on the ZIF-8. The experimental and computations studies provide a new insight for the sophisticated design of ZIF-8 nanostructures for removing organic pollutants efficiently through the combined adsorption and degradation under solar light irradiation. [ABSTRACT FROM AUTHOR]

It is vital to have high sensitivity in gas sensors to allow the exact detection of dangerous gases in the air and at room temperature. In this study, we used 2D MXenes and MoS 2 materials to create a Ti 3 C 2 –MoS 2 composite with high metallic conductivity and a wholly functionalized surface for a significant signal. At room temperature, the Ti 3 C 2 –MoS 2 composite demonstrated clear signals, cyclic response curves to NO 2 gas, and gas concentration-dependent. The sensitivities of the standard Ti 3 C 2 –MoS 2 (TM_2) composite (20 wt% MoS 2) rose dramatically to 35.8%, 63.4%, and 72.5% when increasing NO 2 concentrations to 10 ppm, 50 ppm, and 100 ppm, respectively. In addition, the composite showed reaction signals to additional hazardous gases, such as ammonia and methane. Our findings suggest that highly functionalized metallic sensing channels could be used to construct multigas-detecting sensors that are very sensitive in air and at room temperature. The hypothesized NO 2 -sensing mechanism of the Ti 3 C 2 –MoS 2 composite. [Display omitted] • Formation of Ti 3 C 2 –MoS 2 composite from MXenes and MoS 2. • Clear signal and concentration-dependent to NO 2 gas. • Used to construct multigas-detection sensors in the air. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen (H 2) generation derived by water has been considered as a renewable energy to solve environmental problems and global energy crises. Thus, it is necessary to explore the most effective photocatalysts by using multi-cocatalysts, due to an intimate interaction between different components. Therefore, we already synthesized the TiO 2 /Ti 3 C 2 /g-C 3 N 4 (TTC) photocatalyst from g-C 3 N 4 and Ti 3 C 2 MXene via a calcination technique, and applied this composite for H 2 evolution. By making use of titanium atom from Ti 3 C 2 MXene, titanium dioxide (TiO 2) was in-body developed, which leads to form a close heterostructure between metallic material and semiconductors. Besides, g-C 3 N 4 amorphous with highly surface area also contributes to harvest light irradiation during photocatalytic activity. The optimized TTC-450 heterostructure showed a super H 2 generation efficiency than those of pure g-C 3 N 4 and other samples. Besides, TTC-450 sample also exhibited great recyclability after 4 runs. The proposed mechanism illustrates the efficient movement of generated electrons in TTC system, which leads to high H 2 evolution efficiency. Moreover, the obtained results consistently emphasize the TiO 2 /Ti 3 C 2 /g-C 3 N 4 composite would be a unique material for H 2 production and broaden applications of MXene materials. [Display omitted] • TiO 2 /Ti 3 C 2 /g-C 3 N 4 ternary composites are prepared via a calcination method. • Ti 3 C 2 MXenes are used as a precursor for in situ transformation of TiO 2 phases. • TiO 2 /Ti 3 C 2 /g-C 3 N 4 photocatalyst exhibits a remarkable H 2 evolution performance. • A proposed mechanism for H 2 evolution toward TiO 2 /Ti 3 C 2 /g-C 3 N 4 was illustrated. [ABSTRACT FROM AUTHOR]