The TiO2|Pt photocatalyst panels (effective area 3.5 × 3.5 cm 2 ) were mounted on a custom-made, air-tight PEEK reactor equipped with a quartz window (Figure ; Figure ). 12 mL of the carbonate buffer with LCC enzyme (concentration: 1 µM) and a piece of transparent PET film (weight ~ 240 mg) was added to the reactor and then properly sealed. The solution was purged with N2 (with 2% CH4 as an internal standard) and the reactor was then placed in a calibrated Newport Oriel solar simulator (AM 1.5G, 100 mW cm -2 ). The steadystate temperature inside the reactor was measured to be ~33 ºC and the solution was not stirred during the experiment. Aliquots of the solution were taken at regular time intervals for estimating the hydrolysis of PET using HPLC-UV and the gas from the headspace (50 µL) was analyzed for H2 evolution using GC (discussed below). The control experiment was carried out in pure blank buffer.