Biomass materials have attracted the attention of environmental experts due to their innocuity, low cost, and renewability [
21]. Many studies have successfully loaded nanocatalysts onto various biomass materials. For example, Gao et al. [
22] used corn cob powder as the carbon source to fabricate C/Fe
3O
4/Bi
2O
3 and the composite photocatalyst showed a high removal ability for tetracycline. Xu et al. [
23] proposed a novel pyrolysis-loading process to load zero-valent irons on biochar, where the obtained BC-ZVI could efficiently adsorb As(III) and As(V). Combining the pyrolysis process with ultrasonication, Alsaiari successfully prepared AC/TiO
2 nanocomposites, and the used biomass AC was processed from date seeds [
24]. New TiO
2-carbon microsphere composite materials were synthesized by Peñas-Garzón et al. [
25] through the solvothermal procedure, presenting good visible light degradation performance towards diclofenac. However, the biomass materials mentioned above were used in the form of carbon, and the preparation processes required high energy consumption and complex operation. Until now, few researchers have attempted to directly use natural biomass to support nano-photocatalysts. In our previous study [
26], we successfully loaded BiOBr nanosheets on the vein surfaces of a natural Osmanthus tree leaf through a simple wet dripping process. The main components of the natural leaf veins were cellulose, hemicellulose and lignin, and these substances were non-toxic and biodegradable. Second, there were abundant hydroxyl (–OH) and carboxyl (–COOH) groups in the long chains in the molecular structures of the leaf veins, providing a benefit to the adsorption of metal-precursor and pollutant molecules [
27,
28]. Third, the leaf veins with a 3D ramified architecture could provide plenty of space for the growth of the photocatalyst nanoparticles. Moreover, the leaf veins were lightweight and flexible, enabling the vein-based photocatalysts to float on the wastewater, which could greatly simplify the separation and recovery process of the nanocomposites. Using the natural leaf veins as a photocatalyst carrier was verified to be a feasible and promising strategy.