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Developing interfacial connections is one of the breakthrough strategies to improve the photocatalytic activity. Herein, ZnBi2O4 nanoparticles-ZnO nanorods heterojunction was successfully synthesized and used, as a dual-function photocatalyst, for photocatalytic degradation of Bisphenol A and hydrogen production with improved photocatalytic activity under simulated sunlight irradiation. The highest H2 production (3.44 mmol g−1 h−1) was obtained for ZnO-20 wt% ZnBi2O4 sample, which is around 12.7 times higher than pure ZnO. According to the HRTEM result, the intimate interfacial connections are formed between ZnO and ZnBi2O4 which could act as trapping centers for charge carriers and results in the boosted photocatalytic activity. Further, a high aspect ratio of 1D ZnO nanorods and small size of 0D ZnBi2O4 nanoparticles (~10 nm) increases the number of interfacial contacts and thus the charge carriers’ recombination was suppressed more efficiently. Based on the trapping experiments, ESR and Mott-Schottky analysis, ZnBi2O4–ZnO hybrid photocatalyst followed the S-scheme charge transfer mechanism.

Surface modification for templated synthesis is crucial to achieving three-dimensional (3D) architectured materials for catalysis, photonics, energy storage, etc. However, the existing facile and versatile modification methods (e.g. with dopamine and catechol) generate modification layers that are unstable in harsh environments. These methods are thus unsuitable for electrical applications. Here we report that Ce4+ can act as an effective surface modification reagent for a broad range of substrates (chitinous butterfly wings, carbon paper, nickel foam, and polyethylene terephthalate planks) with various structural features owing to its strong oxidizing ability and Lewis acid nature. The modification yields discrete CeO2 seed layers on substrate surfaces in ca. 0.25-2 h, important for the subsequent conformal growth of CeO2 nanoparticles, Ni(OH)2 nanowires, FeOOH nanosheets, and WO3 nanosheets into 3D architectured materials. The conformally synthesized FeOOH on nickel foam (NF) yields an overpotential of 241 mV at 10 mA cm-1 for an oxygen evolution reaction. This value is comparable to a typical catalyst Ni(Fe)OOH-NF for which the Ni/Fe ratio must be well-optimized. This facile and versatile strategy might have broad applications in the conformal fabrication and application of 3D architectured materials, especially when applied in electrical applications of architectured materials (e.g. Li-ion battery).

In this work, novel Bi2WO6-ZnBi2O4 p-n heterojunction was successfully synthesized through combination of sonochemical and hydrothermal procedures. The results revealed that the sonochemically prepared nanocomposites had spherical shape with amorphous structure which became crystalline particles with flak-like morphology after hydrothermal treatment. Bi2WO6-ZnBi2O4 nanocomposite with 20 wt% ZnBi2O4 content demonstrated the highest photocatalytic performance compared to the pure Bi2WO6 and ZnBi2O4 samples toward the degradation of Malachite Green (MG). This finding is associated with the efficient separation of photo-generated electron/hole pairs due to the formation of interfacial charge transfer between Bi2WO6 and ZnBi2O4. However, further ZnBi2O4 loading had no significant effect on the enhancement of photocatalytic activity of nanocomposite samples owing to the shielding effect of ZnBi2O4 against incident light. The obtained results were further verified by optical and photocurrent density measurements. Based on the obtained results from active species trapping experiments, electron spin resonance and Mott-Schottky calculations, the Z-scheme charge transfer pathway was proposed as the predominant mechanism for the photocatalytic reactions. Also, the photocatalytic degradation of 2,4-dichlorophenol, as a colorless model pollutant, was conducted on optimal composite sample to study the possible contribution of MG dye sensitization mechanism in the enhancement of photocatalytic efficiency.

The Ag doped CoTiO3 (Ag-CTO) and Ag doped CoTiO3/Chitosan–amylopectin (Ag-CTO/CSAP) were prepared using hydrothermal method for photocatalysis under sunlight irradiation. The optical and morphological properties were studied by different analysis devices. Optical analysis shows a reduction in the band-gap energy of Ag-CTO/CSAP nanocomposites. Photocatalytic activity of the Ag-CTO and Ag-CTO/CSAP was studied. The Ag-CTO/CSAP nanocomposites gained the highest catalytic activity (96.74%) for degradation of Crystal-Violet (CV) dye as an organic dye pollutant under sunlight irradiation in 40 min. This improvement could be due to high surface area, the hybrid effect of the adsorption-degradation process, and decreasing the band-gap energy. Therewith, the Ag-CTO/CSAP nanocomposites have substantial bactericidal and fungicidal properties against P. aeruginosa, S. pneumoniae, A. niger, and C. albicans.

In this project, the Au and Ce co-doped SnS2 decoration on hyperbranched polyethyleneimine (Au/Ce/SnS2/HPEI) nanocomposites were prepared via wet/hydrothermal chemical method. Compared with pure SnS2 and co doped SnS2, Au/Ce/SnS2/HPEI nanocomposite indicated higher photo-degradation performance for the reduction of chromium (VI) under visible light irradiation. Therewith, Au/Ce/SnS2/HPEI nanocomposites was applied for photo-degradation of drug. The possible mechanism shows the superoxide anion radical ( O2−) plays important role in in the removal of Cr(VI). The Au/Ce/SnS2/HPEI nanocomposites shows the best photocatalysis activity for water reduction. The prepared Au/Ce/SnS2/HPEI displayed excellent antifungal activity against Aspergillus niger and Candida albicans fungi.

In this project, Sn-Fe bimetallic nanoparticles were prepared by a facile method. The bimetallic nanoparticles of it could be well established by a field emission scanning electron microscope micrographs. Due to the excellent synergistic influence between Sn-Fe nanoparticles and leucine indicated a great performance for determination of Cr3+. The material was characterized using the XRD, DLS, and zetasizer for the evaluation of crystal structure and morphology information. The potential and effective size of Sn-Fe NPs was −29.10 mV and 30 nm, respectively. Cr3+ ions interaction with the Sn-Fe NPs-leucine probe was carried out in 1 min as response time. The limit of detection of Sn-Fe NPs for Cr(III) colorimetric method was 0.25 nM. The prepared nanoparticles showed impressive photocatalysis efficiency for degradation of MO was about 95.1% in 35 min, thus the prepared nanoparticles may be developed for the detoxification of pollution. The prepared nanoparticles depicted effective antibacterial activity against C. botulinum and, H. pylori bacteria.

The catalysis of hydrogen oxidation reaction (HOR) at the anode is one of the most important topics in achieving high-performance proton exchange membrane fuel cells, especially in the presence of hydrogen fuel impurities and during the start-up/shutdown cycling and cell reversal. To improve catalytic HOR performance, Iridium-Ruthenium alloy (IrRu) catalysts have been explored to address the issues. For fundamental understanding of the catalytic HOR activities, this paper employs density functional theory (DFT) calculations to elucidate and interpret the surface modifications and Ru content effect on hydrogen adsorption energy of the IrRu alloys. The catalytic HOR activity trend of the alloyed IrRu catalysts is calculated to be Ir3Ru > IrRu > IrRu3, which is opposite to that experimentally observed. However, if the surface enrichment of Ir atoms on the IrRu surfaces to form core-shell type catalysts, the calculated trend becomes to IrRu3 > IrRu > Ir3Ru, which is in agreement with the experiment result. In spite of higher surface energy on IrRu3 core-shell surface, the compelling d-band downshift can attribute to the surface charge depletion, decreasing hydrogen adsorption energy, and resulting in the highest catalytic activity. For Ir3Ru core-shell catalyst, a relatively higher charge accumulation on the surface Ir is observed, which can up-shift the d-band and increase hydrogen adsorption, resulting the lowest catalytic activity. The IrRu catalyst has intermediate d-band downshift and hydrogen adsorption energy so that its catalytic activity remains between IrRu3 and Ir3Ru for both alloyed and core-shell structures.