Periodic intense illumination in gas-solid phase photocatalysis: Efficient VOCs degradation at extremely low duty cycles

In this study, we report efficient gas–solid phase photocatalytic reaction by employing controlled periodic illumination, intense pulsed light (IPL) technique, at extremely low duty cycles. Compared with traditional continuous illumination, IPL exhibits superior photocatalytic performance, excellent economic advantages and extremely low duty cycles. Up to now, it is the first time that IPL has been applied in gas–solid phase photocatalytic reactions coupled with multiple photocatalysts. It is demonstrated by experiments that the pulsed xenon lamps can release a large number of photons in short pulsed time, leading to a much stronger photocurrent response than that triggered by a conventional xenon lamp. Taking photocatalytic benzenes degradation as the target reaction, in-situ EPR confirmed that the IPL system can generate a large number of reactive radicals, and thus can degrade benzenes efficiently even with almost negligible illumination period.