We have examined the reforming of methanol and CO on Pd/P25 TiO₂ catalysts for hydrogen production, and compared it with rates for similarly supported Au and Cu catalysts. Both reactions proceed, but the photocatalytic water–gas shift (WGS) reaction is much slower than for methanol reforming. CO₂ is evolved as expected, but the yields can be much lower than for the expected stoichiometry (CH₃OH + H₂O → CO₂ + 3H₂). We show that this is due to dissolution of the carbon dioxide into the aqueous phase. We have also carried out both reactions in the gas phase. Both proceed at a higher rate in the gas phase, and for methanol reforming, there is some CO evolution. In H₂ + CO₂ reactions, there is little sign of the reverse WGS reaction, but some photo-methanation does occur. Of the three catalysts Pd is the best for the methanol reforming reaction, while Au is best for the water–gas shift. Nonetheless, Cu works reasonably well for methanol reforming and makes a much cheaper, earth-abundant catalyst.

我们已经研究了用于制氢的 Pd/P25 TiO ₂催化剂上甲醇和 CO 的重整，并将其与类似负载的 Au 和 Cu 催化剂的速率进行了比较。两个反应都在进行，但光催化水煤气变换 (WGS) 反应比甲醇重整慢得多。CO ₂按预期释放，但产率可能比预期的化学计量（CH ₃ OH + H ₂ O → CO ₂ + 3H ₂）低得多。我们表明这是由于二氧化碳溶解在水相中。我们还在气相中进行了这两种反应。两者都在气相中以更高的速率进行，对于甲醇重整，会产生一些 CO。在 H ₂+ CO ₂反应，几乎没有逆 WGS 反应的迹象，但确实会发生一些光甲烷化。在这三种催化剂中，Pd 最适合甲醇重整反应，而 Au 最适合水煤气变换。尽管如此，Cu 对甲醇重整的效果相当好，并且可以制成更便宜、地球资源丰富的催化剂。