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The Ce‐CdS‐TiO2 photocatalysts were successfully synthesized by a simple sol‐gel way and loaded on the nickel foam. The specific surface area, crystalline phase, microstructure and surface functional groups of prepared photocatalysts were characterized by Brunauer‐Emmett‐Teller (BET) surface area, X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT‐IR). The photocatalytic tests of Ce‐CdS‐TiO2 samples demonstrated that Ce as the active component plays an irreplaceable role in degradation of gaseous formaldehyde. The results showed that high Ce doping levels restrained the photocatalytic activity due to lower specific surface area, whereas moderate doping levels showed the highest photocatalytic performance due to higher specific surface area and evenly dispersion of the active component. The rate of formaldehyde degradation on 0.9 wt % Ce‐CdS‐TiO2, 1.5 wt % Ce‐CdS‐TiO2, and 2.1 wt % Ce‐CdS‐TiO2 photocatalysts can reach to 59, 84, and 49 %, respectively, which are higher than pure TiO2 (20 %). Ce‐doping into CdS‐TiO2 photocatalyst produce the Ce‐O‐Ti bonds, which enhanced the interaction between Ce and TiO2. The introduction of Ce increased the UV/Vis absorption of Ce‐CdS‐TiO2 photocatalyst. Furthermore, Ce‐CdS‐TiO2 possesses high photocatalytic performance, since Ce may reduce the recombination of photoexcited electrons and holes.

This study focused on measuring the concentration of formaldehyde in furniture markets, malls, hotels, and restaurants in Guilin, Liuzhou, and Nanning in Guangxi, China. Correlations between the indoor formaldehyde concentration and temperature, humidity, and air change rate were also obtained. The sixty sampled public places selected for this study represented the typical public indoor environment in Guangxi. The percentages of measured formaldehyde concentrations exceeding the standard (0.1 mg m -3 ) in furniture markets, malls, and hotels were 94%, 87%, and 20%, respectively. The highest concentrations measured in furniture markets, malls, hotels, and restaurants were 0.313 mg m ). This work shows that wood-related decorations and merchandise that contain high levels of formaldehyde are the major sources of formaldehyde pollution in indoor environments. Further analysis demonstrates that strong correlations (r > 0.80, p < 0.01) exist between the indoor formaldehyde concentration and temperature, humidity, and air change rate, which indicate that these environmental factors appear to be additional key reasons for the high levels of indoor formaldehyde pollution. The results show that a decrease in temperature and humidity or an increase in air change can effectively alleviate the level of indoor formaldehyde pollution. The findings of this study further promote the development of measures to control indoor air pollution.

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