The Influence of Active Phase Loading on the Hydrodeoxygenation (HDO) of Ethylene Glycol over Promoted MoS2_{2}/MgAl2_{2}O4_{4} Catalysts

The hydrodeoxygenation (HDO) of ethylene glycol over MgAl$_{2}$O$_{4}$ supported NiMo and CoMo catalysts with around 0.8 and 3 wt% Mo loading was studied in a continuous flow reactor setup operated at 27 bar H$_{2}$ and 400 °C. A co-feed of H2S of typically 550 ppm was beneficial for both deoxygenation and hydrogenation and for enhancing catalyst stability. With 2.8-3.3 wt% Mo, a total carbon based gas yield of 80-100 % was obtained with an ethane yield of 36-50 % at up to 118 h on stream. No ethylene was detected. A moderate selectivity towards HDO was obtained, but cracking and HDO were generally catalyzed to the same extent by the active phase. Thus, the C2/C1 ratio of gaseous products was 1.1-1.5 for all prepared catalysts independent on Mo loading (0.8-3.3 wt%), but higher yields of C1-C3 gas products were obtained with higher loading catalysts. Similar activities were obtained from Ni and Co promoted catalysts. For the low loading catalysts (0.83-0.88 wt% Mo), a slightly higher hydrogenation activity was observed over NiMo compared to CoMo, giving a relatively higher yield of ethane compared to ethylene. Addition of 30 wt% water to the ethylene glycol feed did not result in significant deactivation. Instead, the main source of deactivation was carbon deposition, which was favored at limited hydrogenation activity and thus, was more severe for the low loading catalysts

Hydrodeoxygenation (HDO) of aliphatic oxygenates and phenol over NiMo/MgAl2_{2}O4_{4}: Reactivity, inhibition, and catalyst reactivation

This study provides new insights into sustainable fuel production by upgrading bio-derived oxygenates by catalytic hydrodeoxygenation (HDO). HDO of ethylene glycol (EG), cyclohexanol (Cyc), acetic acid (AcOH), and phenol (Phe) was investigated using a Ni-MoS$_{2}$/MgAl$_{2}$O$_{4}$ catalyst. In addition, HDO of a mixture of Phe/EG and Cyc/EG was studied as a first step towards the complex mixture in biomass pyrolysis vapor and bio-oil. Activity tests were performed in a fixed bed reactor at 380–450 °C, 27 bar H2, 550 vol ppm H2S, and up to 220 h on stream. Acetic acid plugged the reactor inlet by carbon deposition within 2 h on stream, underlining the challenges of upgrading highly reactive oxygenates. For ethylene glycol and cyclohexanol, steady state conversion was obtained in the temperature range of 380–415 °C. The HDO macro-kinetics were assessed in terms of consecutive dehydration and hydrogenation reactions. The results indicate that HDO of ethylene glycol and cyclohexanol involve different active sites. There was no significant influence from phenol or cyclohexanol on the rate of ethylene glycol HDO. However, a pronounced inhibiting effect from ethylene glycol on the HDO of cyclohexanol was observed. Catalyst deactivation by carbon deposition could be mitigated by oxidation and re-sulfidation. The results presented here demonstrate the need to address differences in oxygenate reactivity when upgrading vapors or oils derived from pyrolysis of biomass

Operando XAS/XRD and Raman Spectroscopic Study of Structural Changes of the Iron Molybdate Catalyst during Selective Oxidation of Methanol

The structural changes of an iron molybdate/molybdenum oxide (Mo/Fe=2.0) catalyst for the selective oxidation of methanol to formaldehyde were studied using combined operando X‐ray absorption spectroscopy (XAS) and X‐ray diffraction (XRD) as well as operando Raman spectroscopy. Under operating conditions, the Mo K‐edge XANES spectra showed a transition from a mixture of α‐MoO$_{3}$ and Fe$_{2}$(MoO$_{4}$)$_{3}$ towards only Fe$_{2}$(MoO$_{4}$)$_{3}$. XRD and Raman spectroscopy also showed disappearance of the α‐MoO3 phase with time on stream. The results evidenced that the α‐MoO3 component evaporated completely, while the Fe$_{2}$(MoO$_{4}$)$_{3}$ component remained stable. This was linked to a decrease in catalytic activity. Further studies unraveled that the rate of α‐MoO$_{3}$ evaporation increased with increasing MeOH concentration, decreasing O$_{2}$ concentration and increasing temperature. The simultaneous measurements of catalytic activity and spectroscopy allowed to derive a structure‐activity relationship showing that α‐MoO$_{3}$ evaporation needs to be prevented to optimize MoO$_{3}$‐based catalysts for selective oxidation of methanol

Delivering beneficial microorganisms for corals: rotifers as carriers of probiotic bacteria

The use of Beneficial Microorganisms for Corals (BMCs) to increase the resistance of corals to environmental stress has proven to be effective in laboratory trials. Because direct inoculation of BMCs in larger tanks or in the field can be challenging, a delivery mechanism is needed for efficient transmission of the BMC consortium. Packaged delivery mechanisms have been successfully used to transmit probiotics to other organisms, including humans, lobsters, and fish. Here, we tested a method for utilizing rotifers of the species Brachionus plicatilis for delivery of BMCs to corals of the species Pocillopora damicornis. Epifluorescence microscopy combined with a live/dead cell staining assay was used to evaluate the viability of the BMCs and monitor their in vivo uptake by the rotifers. The rotifers efficiently ingested BMCs, which accumulated in the digestive system and on the body surface after 10 min of interaction. Scanning electron microscopy confirmed the adherence of BMCs to the rotifer surfaces. BMC-enriched rotifers were actively ingested by P. damicornis corals, indicating that this is a promising technique for administering coral probiotics in situ. Studies to track the delivery of probiotics through carriers such as B. plicatilis, and the provision or establishment of beneficial traits in corals are the next proof-of-concept research priorities

A methodology for the evaluation of competition policy

The paper develops a methodology for the evaluation of competition policy. Based on the existing literature and experiences with policy evaluations in other areas of economic activity, the three-step / nine-building-blocks methodology provides guidance for evaluation projects and also assists in the identification of avenues for further academic research