Low-temperature steam reforming of phenol for hydrogen production over Co/Al2O3-ash catalysts

A low-cost, high-performance catalyst for phenol steam reforming (PSR) at low temperature was prepared by introducing waste coal ash into Co/Al2O3. The optimized content of coal ash in the catalyst were ranged from 50 to 65 wt%, presenting over 97% phenol conversion and 92% H-2 yield at low temperature of 450 C. The stability for the best catalyst with an ash content of 50 wt% exceeded 85 h. Two-step reduction of Co3O4 to Co0 via CoO was identified by in-situ XRD. DFT calculations showed that phenol adsorption and decomposition were preferred on the FeCo bimetal surface rather than the single Co surface. H2O adsorption and dissociation fascinated on the CaO incorporated Al2O3 surface. Both Fe and Ca in the coal ash improved the catalyst performance in PSR at low temperature. This work gives an opportunity to solve the drawbacks of high reaction -temperature and low catalyst-stability in PSR, and furthermore benefits to get a deep insight into the reaction mechanism of PSR over the catalyst.