Selective production of hydrogen via oxidative steam reforming of methanol using Cu–Zn–Ce–Al oxide catalysts

Abstract

The oxidative steam reforming of methanol (OSRM) was carried out to produce the hydrogen selectively for polymer electrolyte membrane (PEM) fuel cell applications over Cu–Zn–Ce–Al oxide and Cu–Zn–Al oxide catalysts of varying compositions prepared by co-precipitation method. Catalyst performance was evaluated in a packed bed reactor over a wide range of operating conditions, and reaction parameters were optimized in order to maximize the hydrogen production with minimum carbon monoxide formation. The incorporation of ceria in Cu–Zn–Al oxide catalysts enhanced the activity greatly compared to without it. The Cu/Zn/Ce/Al:30/20/10/40 exhibited 100% methanol conversion and 244 mmol s - 1 kg cat - 1 hydrogen rate at 553 K with carbon monoxide as low as 995 ppm, which reduces the load on preferential oxidation of CO to CO 2 significantly before feeding the hydrogen rich stream to the PEM fuel cell as a feed. Ceria had improved the dispersion and specific surface area of copper in multi-component Cu–Zn–Ce–Al oxide catalysts which were confirmed by the physicochemical properties, X-ray diffraction (XRD), temperature programmed reduction (TPR) and CO chemisorption studies. The chemisorption studies were performed at 193 K in order to hinder the spillover of carbon monoxide to ceria. The time-on-stream stability test had shown Cu–Zn–Ce–Al oxide catalysts as more stable compared to Cu–Zn–Al oxide catalysts. The amount of carbon deposited onto the catalysts was determined using TG/DTA thermogravimetric analyzer and the type of carbon species were identified using C1s X-ray photoelectron spectroscopy (XPS) spectra.