Effects of general zero-valent metals power of Co/W/Ni/Fe on hydrogen production with H₂S as a reductant under hydrothermal conditions

Hydrogen production from water with S^2- as a reductant under hydrothermal conditions is an effective new method, in which S^2- is oxidized into S₂O₃^2-, SO ₃^2- and SO₄^2-. However, the reactor wall had great effect on hydrogen production as large amount hydrogen is produced with Hastelloy C-22 reactor while almost no hydrogen generated in SUS 316 reactor. Therefore, the influence of main components of Hastelloy C-22 reactor (Co/W/Ni) and SUS 316 reactor (Fe) on hydrogen production with H₂S as the reductant was investigated. The results showed that Fe had negative effect, whereas W, Co and Ni had significant positive effect on improving hydrogen production. These results provided a possible explanation for no hydrogen generated with SUS 316 reactorand some suggestions for improving hydrogen production. The highest hydrogen production of 199 mL (2 times than the control) was obtained with 4.00 mmol Co, 4.00 mmol W, and 1.00 mmol Ni.