H₂ Production and CO₂ Inhibition during Pyro-Steam Gasification of Municipal Solid Wastes Using a Ni–Zn/CaO-C Catalyst

The study presents a novel Ni–Zn/CaO-C bimetallic dual-supported catalyst for pyro-steam gasification of municipal solid waste (MSW), designed to enhance the H2 yield while inhibiting CO2 production. Key experimental factors, including water flow rate, pyrolysis temperature, reforming temperature, and catalyst composition, were optimized. Zn, as a promoter with Ni, lowers CO2 emissions and increases H2 purity, while CaO adsorbs CO2 and prevents coke deposition on Ni active sites. Char as a carbon support improves the catalytic activity and process sustainability. Ni–Zn/CaO-C demonstrated superior performance with a high H2 yield (652 mL/g) and low CO2 yield (80 mL/g), compared to Ni/CaO-C (510 mL/g H2, 153 mL/g CO2) under optimal conditions. Characterization via X-ray diffraction analysis (XRD), energy dispersive X-ray (EDX), and thermogravimetric analysis (TGA) confirmed the catalyst’s effectiveness.