Methanol steam reforming over copper supported on apatites

Low-temperature methanol steam reforming (MSR) over Cu is an efficient process for releasing H-2 from this promising liquid hydrogen carrier but the Cu contents of commercial catalysts are often exceedingly high. Here we show that Sr-exchanged fluoro and hydroxyapatites with 1 wt% Cu exhibit very high methanol turnover frequencies up to 386 h(-1) and H-2 production rates up to 6569 mol H-2 kg(Cu)(-1) h(-1) with CO selectivity as low as similar to 0.25 % at 250 degrees C. Formaldehyde and methyl formate are the only other byproducts which are especially observed over catalysts with low Sr/P ratio in the hydroxyapatite. The reforming proceeds through methoxy, formaldehyde and formate species according to in situ FTIR and mass spectrometric measurements. The spectroscopic analyses further reveal the involvement of apatitic HPO42- ions in the catalytic sequence. Thus, the catalytic synergy between Cu and apatites provides a basis for highly efficient, bifunctional MSR catalysts with low copper content.