Incorporating another transition metal into gold-based catalysts has been shown to be beneficial to their catalytic performance. To better understand the origin of this catalytic behavior, Au–Pt alloy catalysts supported on thermally stable TiO₂ nanotubes (TiO₂ SNTs) were prepared, and their structural properties, adsorption of CO, and catalytic activity for CO oxidation were investigated. The alloy structure was confirmed by STEM and UV-vis spectroscopy, and the Au–Pt alloy phase could enhance the metal–support interaction (MSI). The catalytic results and DFT analysis indicated that the Au–Pt/TiO₂ SNTs calcined at 400 °C with an Au/Pt ratio = 5 : 1 had the best CO catalytic performance. Based on the XPS and DRIFT results, the synergetic effects between Au and Pt and the hydroxyl groups of the Au–Pt/TiO₂ SNT catalysts played a vital role in the catalytic activity. The hydroxyls bonded onto the cationic Au can react with CO molecules adsorbed on the surface of Au or Pt NPs to form intermediates COOH. The accompanying density functional theory (DFT) calculation results also reveal the determining role of OH in Au–Pt/TiO₂ SNT catalysts. A possible catalytic mechanism of the Au–Pt/TiO₂ SNT catalysts with enhanced catalytic activity was also proposed.

Oriented TiO₂ nanotubes, which are fabricated by anodic oxidation method, are prospective in photoelectrochemical analysis and sensors. In this work, Pt and IrO₂ co-modified TiO₂ nanotubes array was prepared via a two-step deposition process involving the photoreductive deposition of Pt and chemical deposition of IrO₂ on the oriented TiO₂ nanotubes. Due to the improved separation of photo-generated electrons and holes, Pt-IrO₂ co-modified TiO₂ nanotubes presented significantly higher PEC activity than pure TiO₂ nanotubes or mono-modified TiO₂ nanotubes. The PEC sensitivity of Pt-IrO₂ co-modified TiO₂ nanotubes for glutathione was also monitored and good sensitivity was observed.

The gold catalysts supported on various morphologies of α-Fe₂O₃ in carbon monoxide (CO) oxidation reaction have been studied for many researchers. However, how to improve the catalytic activity and thermal stability for CO oxidation is still important. In this work, an unusual morphology of α-Fe₂O₃ was prepared by hydrothermal method and gold nanoparticles were supported using a deposition-precipitation method. Au/α-Fe₂O₃ catalyst exhibited great activity for CO oxidation. The crystal structure and microstructure images of α-Fe₂O₃ were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the size of gold nanoparticles was determined by transmission electron microscopy (TEM). X-ray photoelectron spectra (XPS) and Fourier transform infrared spectra (FTIR) results confirmed that the state of gold was metallic. The 1.86% Au/α-Fe₂O₃ catalyst calcined at 300 °C had the best catalytic performance for CO oxidation reaction and the mechanism for CO oxidation reaction was also discussed. It is highly likely that the small size of gold nanoparticle, oxygen vacancies and active sites played the decisive roles in CO oxidation reaction.

Based on the enhanced charge separation efficiency of the one-dimensional structure and strong surface plasmon resonance (SPR) of gold, a gold modified TiO₂ nanotube (Au/TiO₂NTs) glucose photoelectrochemical (PEC) sensor was prepared. It could be activated by visible red light (625 nm). Under optimal conditions, the Au/TiO₂NTs sensor exhibited a good sensitivity of 170.37 μA·mM⁻¹·cm⁻² in the range of 1–90 μM (R² = 0.9993), and a detection limit of 1.3 μM (S/N = 3). Due to its high selectivity, good anti-interference ability, and long-term stability, the fabricated Au/TiO₂NTs sensor provides practical detection of glucose. It is expected to be used in the construction of non-invasive PEC biosensors.