This work presents a systematic study of cellulose (CLS) as a sacrificial biomass for photocatalytic H₂ evolution from water. The idea is indeed to couple a largely available and not expensive biomass, and water, with a renewable energy like solar radiation. An aqueous CLS suspension irradiated either at 366 nm (UV-A) or under sunlight in the presence of Pt/TiO₂ behaves as a H₂ evolving system. The effects of irradiation time, catalyst and CLS concentrations, pH and water salinity are studied. Addition of CLS to the sample significantly improved H₂ evolution from water splitting, with yields up to ten fold higher than those observed in neat water. The mechanism of the photocatalytic process relies on the TiO₂-mediated CLS hydrolysis, under irradiation. The polysaccharide depolymerisation generates water-soluble species and intermediates, among them 5-hydroxymethylfurfural (HMF) was identified. These intermediates are readily oxidized following the glucose photoreforming, thus enhancing water hydrogen ion reduction to give gas-phase H₂. The formation of “colored” by-products from HMF self-polymerization involves a sort of “in situ dye sensitization” that allows an effective photoreaction even under solar light. The procedure is evaluated and successfully extended on cellulosic biomasses, i.e. rice husk and alfalfa (Medicago sativa) stems, not previously investigated for this application.

Heterogeneous photocatalysis is one of the most studied and promising techniques for degradation of contaminants of emerging concern, especially pharmaceuticals, and it represents a potential application in wastewater treatment of recalcitrant pollutants, such as fluoroquinolones, which are almost not abated by standard WWTPs. Although photodegradation partially contributes to alleviate their accumulation into the aquatic systems, heterogeneous photocatalysis assures complete sequestration and mineralization of FQs and their photoproducts and offers many advantages with respect to the other advanced oxidation processes (AOPs). The present brief review summarizes the most recent studies regarding the development and application of novel photocatalytic materials to the removal of FQs from contaminated waters. The collected data are arranged relating the mechanistic aspects to specific catalysts’ properties, such as adsorption capacity, easy recovery, and reusability, especially under actual conditions. Graphical Abstract