The basic scenario of resistive switching in TiO₂ (Jameson et al., 2007) assumes the formation and electromigration of oxygen vacancies between the electrodes (Baiatu et al., 1990), so that the distribution of concomitant n-type conductivity (Janotti et al., 2010) across the volume can eventually be controlled by an external electric bias, as schematically shown in Figure 1B. Direct observations with transmission electron microscopy (TEM) revealed more complex electroforming processes in TiO₂ thin films. In one of the studies, a continuous Pt filament between the electrodes was observed in a planar Pt/TiO₂/Pt memristor (Jang et al., 2016). As illustrated in Figure 1C, the corresponding switching mechanism was suggested as the formation of a conductive nanofilament with a high concentration of ionized oxygen vacancies and correspondingly reduced Ti³⁺ ions. These ions induce detachment and migration of Pt atoms from the electrode via strong metal–support interactions (Tauster, 1987). Another TEM investigation of a conductive TiO₂ nanofilament revealed it to be a Magnéli phase Ti_nO_2n−1 (Kwon et al., 2010). Supposedly, its formation results from an increase in the concentrations of oxygen vacancies within a local nanoregion above their thermodynamically stable limit. This scenario is schematically shown in Figure 1D. Other hypothesized point defect mechanisms involve a contribution of cation and anion interstitials, although their behavior has been studied more in tantalum oxide (Wedig et al., 2015; Kumar et al., 2016). The plausible origins and mechanisms of memristive switching have been comprehensively reviewed in topical publications devoted to metal oxide memristors (Yang et al., 2008; Waser et al., 2009; Ielmini, 2016) as well as TiO₂ (Jeong et al., 2011; Szot et al., 2011; Acharyya et al., 2014). The resistive switching mechanisms in memristive materials are regularly revisited and updated in the themed review publications (Sun et al., 2019; Wang et al., 2020).

Titanium dioxide is often listed in the ingredients list on the product label when used in home, beauty and personal care products.

Apart from the cosmetics industry, the coatings and plastics industry is also expected to contribute significantly to the growth of titanium dioxide in 2023. Coatings made from titanium dioxide offer excellent hiding power, durability and weather resistance, making them ideal for outdoor applications. Demand for high-quality coatings is expected to surge as the construction and automotive industries expand. Titanium dioxide is at the forefront of providing aesthetic and protective coatings, making it an indispensable ingredient in the industry.

I don't see the scientific evidence in the literature that would cause people any concern, said Kaminski.

In Home Care products, the presence of titanium dioxide is declared in line with local regulations, which can vary across the world. In some countries, titanium dioxide is not declared if only a small amount of the ingredient is used. In other countries titanium dioxide is grouped under ‘colourants’ in the ingredients list. In Europe, regulation requires all home care ingredients to be disclosed through a supporting website. You can find our product ingredient information page by visiting ‘