Self-Promoted H2 Formation: The Feasibility of Photoinduced CO Removal for Lossless Hydrogen Purification

A photoinduced radical reaction operated at low temperature can be used to remove trace CO from a H2 stream by minimizing the reverse water-gas shift. However, H2 consumption resulting from nonselective oxidation by hydroxyl radicals becomes an obstacle to practical hydrogen purification. Inspired by hydrogen exchange transfer, we demonstrate here that molecular hydrogen can promote H2 formation from hydrogen radicals, which are generated from the reaction of CO and H2 with hydroxyl radicals. The slight increment in H2 along with the radical reaction encouraged us to configure a photocatalytic hydrogen purification fixed-bed reactor, which can reduce CO to <1 ppm in the H2 stream.

Automated summary

A photoinduced radical reaction at low temperature effectively removes trace CO from a H2 stream, reducing the reverse water-gas shift. However, nonselective oxidation by hydroxyl radicals leads to H2 consumption hindering practical hydrogen purification. Inspired by hydrogen exchange transfer, molecular hydrogen is found to promote H2 formation from hydrogen radicals generated by the reaction of CO and H2 with hydroxyl radicals. This finding encouraged the design of a photocatalytic hydrogen purification fixed-bed reactor that can reduce CO to <1 ppm in the H2 stream.