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

Abstract

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.