Synthesizing hydrogen from ammonia over Ru incorporated SiO2 type nanocomposite catalysts

•RuO2 crystals 4–10 nm in size were well distributed in the highly ordered mesoporous silicate matrix.•Under GHSVNH3GHSVNH3 of 360,000 ml/h.gcat, conversion was %86 at 500 °C over the catalyst (nRu/nSi: 0.060).•Using KOH greatly enhances the activity of the catalysts.•Under GHSVNH3GHSVNH3 of 6000 ml/h.gcat, 84% conversion was achieved at 400 °C over the promoted catalysts.

In this study, Ruthenium incorporated SiO2 type nanocomposite catalysts were prepared for COx free hydrogen production by using one-pot hydrothermal synthesis procedure. Experiments which were carried out under the flow of pure ammonia (300 ml/min) presented that 86% ammonia conversion was obtained at 500 °C over the catalyst having Ru/Si molar ratio of 0.060. Using promoter in the preparation of catalyst enhanced the catalytic activity especially for the ones prepared at low ruthenium loadings. While the catalyst that was prepared at a Ru/Si molar ratio of 0.010 without promoter gave negligible activity at 500 °C, the promoted one gave 33% conversion at 500 °C and 73% at 600 °C. Experiments were also repeated with lower feed flow rate values of ammonia such as 60 ml/min and 5 ml/min. It was seen that catalyst prepared at a Ru/Si molar ratio of 0.010 with promoter gave conversion value over 80% at 400 °C under the feed flow rate of 5 ml/min.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide