Continuous Room-Temperature Hydrogen Release from Liquid Organic Carriers in a Photocatalytic Packed-Bed Flow Reactor

Despite the potential of hydrogen (H-2) storage in liquid organic carriers to achieve carbon neutrality, the energy required for H-2 release and the cost of catalyst recycling have hindered its large-scale adoption. In response, a photo flow reactor packed with rhodium (Rh)/titania (TiO2) photocatalyst was reported for the continuous and selective acceptorless dehydrogenation of 1,2,3,4-tetrahydroquinoline to H-2 gas and quinoline under visible light irradiation at room temperature. The tradeoff between the reactor pressure drop and its photocatalytic surface area was resolved by selective in-situ photodeposition of Rh in the photo flow reactor post-packing on the outer surface of the TiO2 microparticles available to photon flux, thereby reducing the optimal Rh loading by 10 times compared to a batch reactor, while facilitating catalyst reuse and regeneration. An example of using quinoline as a hydrogen acceptor to lower the energy of the hydrogen production step was demonstrated via the water-gas shift reaction.

Automated summary

A study reported a photo flow reactor using Rh/TiO2 photocatalyst to achieve the selective dehydrogenation of 1,2,3,4-tetrahydroquinoline, reducing the optimal Rh loading by 10 times compared to a batch reactor and facilitating catalyst reuse and regeneration, thus overcoming the energy and cost barriers in hydrogen production reaction.