Steam reforming of bio-oil is a promising technology for the industrial-scale conversion of biomass into hydrogen energy, in which the catalyst plays the crucial role. This study proposes a Ni-Ca-Al-Ce-O catalyst, prepared by CaO loading onto Ni/CeO 2 ·Al 2 O 3 , and tested in the two-stage adsorption-enhanced reforming of biomass pyrolysis oil for hydrogen production. The effects of carrier type and Ni loading on the physicochemical properties of the Ca modified Ni-based reforming catalyst and its reforming performance were investigated, and its reusability was tested finally. The results revealed that more Ni metal active sites are available on CeO 2 ·Al 2 O 3 compared to biochar as carrier. However, side reactions such as ketonization were significantly promoted due to the metal oxides in red mud (RM), resulting in a large amount of methane as a by-product over the Ni/RM catalyst. When Ca additive introduced on the well selected Ni/CeO 2 ·Al 2 O 3 , the selectivity of hydrogen in the reforming gas was enhanced. Meanwhile, more spinel NiAl 2 O 4 was formed due to the interaction between NiO and Al 2 O 3 , which enhanced the stability and activity of the Ni-Ca-Al-Ce-O catalyst. With a Ca/Al ratio of 1:1, Ni was more uniformly dispersed, and the yield and selectivity of hydrogen reached 73.35 % and 76.90 %. In the reusability tests, the yield of hydrogen remained above 60 % after six runs, which was superior to that of similar reforming catalysts, suggesting that the proposed Ni-Ca-Al-Ce-O catalyst is reliable in terms of reusability.
Pengfei Li,Yongjun Liu,Zhuangzhuang Yang,Lu Yang,Pan Liu,Zhe Liu,Xiaowei Li
The complete harmless treatment of aromatic organic compounds in coal chemical wastewater (CCW) has always been a big challenge in water process engineering. This study addresses the issue by designing and preparing a kind of Ce and Al bimetallic catalyst with high oxygen vacancies (OVs) based on SiC carrier. The results showed that CeO 2 and Al 2 O 3 were uniformly dispersed on SiC, and the composite material exhibited an ordered cubic structure. The degradation efficiency and enhancement mechanism of the catalyst with ozone oxidation were investigated. When applied to actual CCW with a chemical oxygen demand (COD) concentration exceeding 600 mg/L, the synergy between O 3 and CeO 2 /Al 2 O 3 -SiC increased the degradation efficiency of phenols from 50 % to 99 % and COD from 42 % to 78 % compared to using O 3 alone. CeO 2 /Al 2 O 3 -SiC had a high concentration of oxygen vacancies (OVs = 48.57 %). Further research indicated that oxygen vacancies (OVs) were the main active sites for ozone adsorption and reactive oxygen species (ROSs) generation. Electron paramagnetic resonance (EPR) and quenching experiments also confirmed that O 3 , •O 2 −1 , 1 O 2 were the main active oxidation factors, rather than •OH. Additionally, even after granulating the catalyst, it still achieved 99 % degradation of phenols. Therefore, this study provides theoretical support for the complete harmless treatment of CCW and has broad prospects for industrial application.
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