BACKGROUND: Since natural cellulose is an insoluble, crystalline microfibril, which is difficult to react with other compounds, most reactions related with cellulose are heterogeneous. The methods of cellulose degradation include acid hydrolysis, thermal degradation, alkaline degradation and catalytic degradation. Photocatalysis is a very powerful process. RESULTS: With 10 g cellulose dissolved in 100 mL ZnCl2 solution (66%), the 5-hydroxymethyl furfural yield in the corrugated plate photocatalytic reactor reached 3.87 g L-1 under the following experimental conditions: 2 h irradiation under ultraviolet (UV) lamp (power - 21 W), nine TiO2 coating cycles, and 42 degrees corrugated plate angle. CONCLUSION: Owing to the enhancement of catalyst surface area illuminated by UV light and the large number of photons captured on the catalyst surface, the energy efficiency per mass (EE/M) of the corrugated plate photocatalytic reactor for photocatalytic degradation of cellulose was 10.9 kWh kg(-1). This is therefore an effective technology for 5-HMF preparation from cellulose. (C) 2011 Society of Chemical Industry