Long‐Term Stable Hydrogen Production from Water and Lactic Acid via Visible‐Light‐Driven Photocatalysis in a Porous Microreactor

Abstract Photocatalytic hydrogen (H 2 ) production is significant to overcome challenges like fossil fuel depletion and carbon dioxide emission, but its efficiency is still far below that which is needed for commercialization. Herein, we achieve long‐term stable H 2 bubbling production from water (H 2 O) and lactic acid via visible‐light‐driven photocatalysis in a porous microreactor (PP12); the catalytic system benefits from photocatalyst dispersion, charge separation, mass transfer, and dissociation of O−H bonds associated with H 2 O. With the widely used platinum/cadmium‐sulfide (Pt/CdS) photocatalyst, PP12 leads to a H 2 bubbling production rate of 602.5 mmol h −1 m −2 , which is 1000 times higher than that in a traditional reactor. Even when amplifying PP12 into a flat‐plate reactor with an area as large as 1 m 2 and extending the reaction time to 100 h, the H 2 bubbling production rate still remains at around 600.0 mmol h −1 m −2 , offering great potential for commercialization.