Carbon dioxide catalytic conversion to nano carbon material on the iron–nickel catalysts using CVD-IP method

The over-consumption of fossil fuels resulted in the large quantity emission of carbon dioxide(CO2), which was the main reason for the climate change and more extreme weathers. Hence, it is extremely pressing to explore efficient and sustainable approaches for the carbon-neutral pathway of CO2 utilization and recycling. In our recent works with this context, we developed successfully a novel "chemical vapor deposition integrated process(CVD-IP)" technology to converting robustly CO2 into the value-added solid-form carbon materials.The monometallic Fe Ni0–Al2O3(FNi0) and bimetallic Fe Nix–Al2O3(FNi2, FNi4, FNi8 and FNi20) samples were synthesized and effective for this new approach. The catalyst labeled FNi8 gave the better performance, exhibited the single pass solid carbon yield of 30%. These results illustrated alternative promising cases for the CO2 capture utilization storage(CCUS), by means of the CO2 catalytic conversion into the solid-form nano carbon materials.

Molybdenum carbide clusters for thermal conversion of CO2 to CO via reverse water-gas shift reaction

Molybdenum carbides are highly active for CO2 conversion to CO via the reverse water-gas shift(RWGS)reaction, however the large grain size up to micrometers renders its relatively lower active sites utilization efficiency while generating CH4 as a by-product. In this work, a homogeneously dispersed molybdenum carbide hybrid catalyst with sub-nanosized cluster(the average size as small as 0.5 nm) is prepared via a facile carbothermal treatment for highly selective CO2-CO reduction. The partially disordered Mo2C clusters are characterized by synchrotron high-resolution XRD and atomic resolution HAADF-STEM analysis, for which the source cause of the disorder is pinpointed by XAFS analysis to be the nitrogen intercalants from the carbonaceous precursor. The partially disordered Mo2C clusters show a RWGS rate as high as 184.4 μmol gMo2C-1s-1 at 400 ℃ with a superior selectivity toward CO(> 99.5%). This work 2 highlights a facile strategy for fabricating highly dispersed and partially disordered Mo2C clusters at a sub-nano size with beneficial N-doping for delivering high catalytic activity and operational stability.

CO_2 selective hydrogenation to synthetic natural gas(SNG) over four nano-sized Ni/ZrO_2 samples:ZrO_2 crystalline phase & treatment impact

Two type zirconia(monoclinic and tetragonal phase ZrO_2) carriers were synthesized via hydrothermal route,and nano-sized zirconia supported nickel catalysts were prepared by incipient impregnation then followed thermal treatment at 300℃ to 500℃,for the CO_2 selective hydrogenation to synthetic natural gas(SNG).The catalysts were characterized by XRD,CO_2-TPD-MS,XPS,TPSR(CH_4,CO_2) techniques.For comparison,the catalyst NZ-W-400(monoclinic) synthesized in water solvent exhibited a better catalytic activity than the catalyst NZ-M-400(tetragonal) prepared in methanol solvent.The catalyst NZ-W-400 displayed more H_2 absorbed sites,more basic sites and a lower temperature of initial CO_2 activation.Then,the thermal treatment of monoclinic ZrO_2 supported nickel precursor was manufactured at three temperature of 350,400,500℃.The TPSR experiments displayed that there were the lower temperature for CO_2 activation and initial conversion(185℃) as well as the lower peak temperature of CH_4 generation(318℃),for the catalyst calcined at 500℃.This sample contained the more basic sites and the higher catalytic activity,evidenced byCO_2-TPD-MS and performance measurement.As for the NZ-W-350 sample,which exhibited the less basic sites and the lower catalytic activity,its initial temperature for CO_2 activation and conversion was higher(214℃) as well as the higher peak temperature of CH_4 formation(382℃).