Hydrogen produced from renewable resources is a promising potential source of clean energy. With the help of low-temperature proton-exchange membrane fuel cells, molecular hydrogen can be converted efficiently to produce electricity1, 2, 3, 4, 5. The implementation of sustainable hydrogen production and subsequent hydrogen conversion to energy is called “hydrogen economy”2. Unfortunately, its physical properties make the transport and handling of hydrogen gas difficult. To overcome this, methanol can be used as a material for the storage of hydrogen, because it is a liquid at room temperature and contains 12.6 per cent hydrogen. However, the state-of-the-art method for the production of hydrogen from methanol (methanol reforming) is conducted at high temperatures (over 200 degrees Celsius) and high pressures (25–50 bar), which limits its potential applications6, 7, 8. Here we describe an efficient low-temperature aqueous-phase methanol dehydrogenation process, which is facilitated by ruthenium complexes. Hydrogen generation by this method proceeds at 65–95 degrees Celsius and ambient pressure with excellent catalyst turnover frequencies (4,700 per hour) and turnover numbers (exceeding 350,000). This would make the delivery of hydrogen on mobile devices—and hence the use of methanol as a practical hydrogen carrier—feasible.
At a glance
Figure 1: Methanol reforming by homogeneous catalysis. 
a, Schematic pathway for a homogeneously catalysed methanol reforming process via three discrete dehydrogenation steps. b, Best-performing catalysts among those tested (see Supplementary Information) for aqueous-phase methanol dehydrogenation performed with 0.5 M NaOH at 72.0 °C.
Figure 2: Approaching ‘real’ aqueous methanol reforming. 
a, Aqueous methanol dehydrogenation using 1.0 p.p.m. of catalyst 2a in a 9:1 ratio of MeOH/H2O containing 8.0 M KOH. b, Set-up for continuous aqueous methanol reforming using 2a. Evolved gas volume (red line) and gas composition (blue bars) as a function of time, with conditions as follows: MeOH/H2O 4:1 (10 ml), NaOH 0.1 M, 2a 49.3 μmol, 250 p.p.m. with respect to MeOH, 72 °C). For details, see Supplementary Table 4.
Figure 3: Proposed catalytic cycle for Ru-promoted aqueous-phase methanol dehydrogenation. 
Proposed catalyst activation and catalytic cycle for low-temperature methanol reforming catalysed by 2c, made in situ from 2a. The phosphorus iPr substituents have been omitted for clarity. ‡ denotes transition state; solvent-H indicates a molecule of solvent involved in hydrogen bonding.
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