Modulating and controlling active species dispersion over Ni–Co bimetallic catalysts for enhancement of hydrogen production of ethanol steam reforming

• Constructing a high-performance H2 production catalyst for ethanol steam reforming.
• The dispersion of catalytic active species was tuned by different preparation methods.
• Ni–Co/Al2O3 catalyst exhibited high species dispersion and high activity.
• High dispersion of active species offered catalyst a high anti-coking property.

In this study, an active Ni–Co/Al2O3 catalyst for steam reforming of ethanol (SRE) was reported. Results indicated that the dispersion of active species can be tuned by preparation methods, i.e., by step—step impregnation method and co-impregnation method separately. By comparing the activities and stabilities in the temperature range of 250–650 °C under atmospheric pressure, and correlating the characterization results of H2 chemisorption, XRD, HRTEM and TGA, we found the catalytic performance were dependent on the surface species dispersion over support which could be modulated by preparation process. The ethanol conversion on Ni–Co/Al2O3, Co/Ni/Al2O3 and Ni/Co/Al2O3 catalysts were 68.7%, 50.9%, 36.6% at 350 °C, corresponding to the metal species dispersion data 31.5%, 29.1% and 28.0%, respectively. TEM results confirmed these differences corresponded to the metal particles size of the bimetallic catalysts distribution. Higher dispersed catalyst exhibited higher anti-coking properties and stabilities. Under the optimized conditions, the ethanol conversion, H2 and CO2 selectivities were 97.2%, 88.9% and 87.4%, respectively during a 100 h reaction over Ni–Co/Al2O3 catalyst at 550 °C, LHSV of 7.5 h−1 and a C2H5OH/H2O molar ratio of 13.

A high active Ni-Co bimetallic catalyst for ethanol steam to hydrogen was reported. Species active dispersion was tuned by preparation method. Higher dispersion makes catalyst exhibiting higher activities and high anti-coking properties.Figure optionsDownload as PowerPoint slide