Multi-contact prismatic spiky block titanium dioxide–graphene covalent composites for formaldehyde degradation

In this study, in situ solvothermal growth was carried out to fabricate multi-contact prismatic spiky block TiO2–graphene covalent composites (PTG) with unique morphologies. Prismatic conical TiO2 projections were uniformly formed on graphene sheets, yielding block PTG with Ti–C and Ti–O–C covalent bonds. The crystal structure and morphological properties of PTG were characterized, and its photocatalytic performance was evaluated. The covalent doping of graphene sheets resulted in the superior gaseous formaldehyde degradation activity of PTG compared to that of prickly spherical TiO2, with a degradation rate of 80.1% under visible light after 120 min. Electron paramagnetic resonance spectroscopy revealed that PTG displayed a sustained radical response and maintained high catalytic activity after five cycles of formaldehyde degradation. The reliable cycling stability and visible-light-induced photocatalytic activity of PTG suggest its potential for application in the field of hazardous gas degradation. •TiO2–graphene covalent composites are suitable for formaldehyde (HCHO) degradation.•Doping of TiO2 with graphene sheets enhances HCHO degradation.•The composite gave a degradation rate of 80.1% under visible light after 120 min.•The composite maintained catalytic activity over five degradation cycles.