Highly dispersed copper on biochar carbon as a promising catalyst for reverse water gas shift reaction

The conversion of CO2 to CO via the reverse water gas shift (RWGS) reaction is the first step in CO2 hydrogenation. This process converts CO2 into valuable compounds, such as methanol, to address the global issue of CO2 emissions. In this paper, the performance of a Cu-based catalyst supported on a biochar substrate (prepared from fig leaves) in RWGS was investigated. Biochar prevents the agglomeration of copper particles due to its high BET surface area, resulting in a significant increase in catalyst stability. Additionally, the presence of regular pores leads to an enhanced dispersion of copper particles on the substrate surface, preventing particle accumulation. The prepared catalysts were characterized by SEM, XRD, FT-IR and BET. Catalytic tests were carried out in a fixed bed reactor at atmospheric pressure and a temperature range of 400-600 degrees C with a different H-2/CO2 ratio. Besides, gas hourly space velocities (GHSV = 28,800 and 187,800 ml g(-1) h(-1)) were assessed. In this study, four different ratios of Cu (10 %, 15 %, 20 % and 25 %) were considered for our experiments. The 20%Cu sample reached the highest CO2 conversion (58 %) and CO selectivity value (>98 %) in 600 degrees C with GHSV = 96,000 ml g(-1) h(-1) for long terms runs. Also, this sample in comparison to industrial Copper-Zinc catalyst displayed significantly higher levels of CO2 conversion and CO selectivity.