Bimetallic Co-Rh Systems as a Prospective Base for Design of CH4 Reforming Catalysts to Produce Syngas with a Controllable Composition

Abstract

Dry and bireforming (CO2-H2O) of methane are the most environmentally friendly routes involving two main greenhouse gases to produce syngas—an important building block for large-scale production of various commodity chemicals. The main drawback preventing their industrial application is the coke formation. Developing catalysts that do not favour or are resistant to coke formation is the only way to improve the catalyst stability. Designing an economically viable catalyst may be achieved by exploiting the synergic effects of combining noble (expensive but coke-resistant) and non-noble (cheap but prone to carbonisation) metals to form highly effective catalysts. This work deals with development of highly active and stable bimetallic Co-containing catalysts modified with small amount of Rh, 0.1–0.5 mass %. The catalysts were characterised by BET, XRD, TEM, SEM, XPS, and TPR-H2 methods and tested in dry, bi-, and for comparison in steam reforming of methane. It was revealed that the bimetallic Co-Rh systems is much more effective than monometallic ones due to Co-Rh interaction accompanied with increasing dispersion and reducibility of Co. The extents of CH4 and CO2 conversion over the 5%Co-Rh/Al2O3 are varied within 85–99%. Syngas with variable H2/CO = 0.9–3.9 was formed. No loss of activity was observed for 100 h of long-term stability test.