ZnO and TiO2 are semiconductor nanomaterials that are widely used in photocatalysis. However, the relatively high recombination rate and low quantum yield of photogenerated electron–hole pairs limit their practical applications. In this study, a series of TiO2/ZnO/diatomite composites with various compositions were successfully prepared via a two-step precipitation method. They exhibited stronger UV–visible absorption properties and substantially lower fluorescence intensities than those of ZnO and ZnO/diatomite, which was mainly due to the low recombination rate of the photogenerated electron–hole pairs in the composite system. The reaction intermediates of methylene blue were detected by liquid chromatography–mass spectrometry, and the degradation process was determined. The best composite catalyst was used for the degradation of gaseous methylbenzene and gaseous acetone. The gaseous acetone degradation product was determined to be acetaldehyde via gas chromatography–mass spectrometry. The results show that the composite catalyst exhibited a good photocatalytic degradation of both liquid pollutants and harmful volatile gases. When applied to the hydrogen and oxygen evolution reactions, the composite catalyst retained a good photoresponsivity and electrolytic efficiency.

The key to the commercialization of sustainable energy conversion technologies is the development of high-performance catalysts. The discovery of a stable, efficient, and low-cost multi-function catalyst is key. We used a simple green precipitation method to load diatomite nanozinc oxide particles onto a diatomite substrate. The ZnO is nano-sized. This precipitation method produces ZnO nanoparticles in situ on diatomite. The catalyst degraded 90% of a Methylene blue solution and also degraded gaseous benzene and acetone. Not only can the catalyst be used for the organic degradation of wastewater, but it also has the potential to degrade volatile organic compounds. Photocatalytic efficiency is closely related to the generation and separation of photosynthetic electrons and holes. The effective suppression of the composite rate of photoliving carriers, and thus improvement of the photocatalytic activity, has become a key research area. At present, At present, photocatalysis is an effective technology to inhibit photocarrier synthesis, which is often studied in sewage treatment. Photocatalytic water treatment reduces the combination of photoelectrons and holes by applying an external bias, thus improving the quantum efficiency for the complete mineralization of organic pollutants. The composite catalyst was used for oxygen and hydrogen extraction reactions, and a comparison of the catalysts with various loading ratios showed that the electrolysis water activity of the in situ loaded catalyst is due to pure ZnO, and the efficiency is highest when the loading ratio is 10%. This work provides new methods for the design and further optimization of the preparation of electrolytic aqueous catalysts.

Magnetic materials are being increasingly used in anti-counterfeiting coatings, but the dark colors of magnetic materials greatly limit their applications.