Methanol-Water Aqueous-Phase Reforming with the Assistance of Dehydrogenases at Near-Room Temperature.

As an excellent hydrogen-storage medium, methanol has many advantages, such as high hydrogen content (12.6 wt %), low cost, and availability from biomass or photocatalysis. However, conventional methanol-water reforming usually proceeds at high temperatures. In this research, we successfully designed a new effective strategy to generate hydrogen from methanol at near-room temperature. The strategy involved two main processes: CH3 OH→HCOOH→H2 and NADH→HCOOH→H2 . The first process (CH3 OH→HCOOH→H2 ) was performed by an alcohol dehydrogenase (ADH), an aldehyde dehydrogenase (ALDH), and an Ir catalyst. The second procedure (NADH→HCOOH→H2 ) was performed by formate dehydrogenase (FDH) and the Ir catalyst. The Ir catalyst used was a previously reported polymer complex catalyst [Cp*IrCl2 (ppy); Cp*=pentamethylcyclopentadienyl, ppy=polypyrrole] with high catalytic activity for the decomposition of formic acid at room temperature and is compatible with enzymes, coenzymes, and poisoning chemicals. Our results revealed that the optimum hydrogen generation rate could reach up to 17.8 μmol h-1  gcat -1 under weak basic conditions at 30 °C. This will have high impact on hydrogen storage, production, and applications and should also provide new inspiration for hydrogen generation from methanol.