Bimodal NdNiAl and NdFeB hybrid catalytic and magnetic nanoparticles laminated on Fe foam: catalytic conversion of CO + 3H₂ to CH₄

Abstract

For the production of CH 4 from CO hydrogenation, a hybrid foam with high catalytic activity and strong magnetic bonding ability was fabricated by electrospraying and co-sintering Nd-doped NiAl catalytic nanoparticles and NdFeB magnetic nanoparticles over a Fe foam. When the NdNiAl nanoparticles were uniformly distributed over a NdFeB nanoparticles support, they exhibited exceedingly high catalytic activity, selective conversion and stable adhesion. In particular, bimodal NdNiAl-NdFeB hybrid nanoparticles (with a ratio of 85.0 to 15.0 wt%) immobilized on Fe foam exhibited a high CO to CH 4 conversion rate, with a TOF value of 1.1 s À1 and a CH 4 selectivity value of 77.1% at a specific temperature of 260.0 C. This improved catalytic behavior was attributed to the enhanced uniform dispersion of NdNiAl nanoparticles over a NdFeB nanoparticles support. At the same time, the NdFeB nanoparticles had high hydrogen absorptivity, which helped adjacent NdNiAl nanoparticles activated with CO to be hydrogenated and produce CH 4 .

Thermo-mechanical improvement of Inconel 718 using ex situ boron nitride-reinforced composites processed by laser powder bed fusion

“…Thus, the BN/IN718 nanosheet/micropowder mixture had a D 50 of 28.3 µm due to the presence of BN nanosheets between the IN718 micropowders, as shown in Supplementary Figure 2c . The size of the BN nanosheets was much smaller than the diameter of the IN718 micropowders, thus the BN nanosheets effectively entered the spaces between the IN718 micropowder particles during the blending process before they were irradiated with the laser beam 48 – 52 . This behavior is in accordance with theory for bimodal systems (nanosheets and micropowders) 48 – 52 .…”

“…The size of the BN nanosheets was much smaller than the diameter of the IN718 micropowders, thus the BN nanosheets effectively entered the spaces between the IN718 micropowder particles during the blending process before they were irradiated with the laser beam 48 – 52 . This behavior is in accordance with theory for bimodal systems (nanosheets and micropowders) 48 – 52 . After this, it was possible to achieve adequate laser fusion of the points of increased contact between the nanosheets and micropowders.…”

“…An IN718 ingot was obtained from a supplier (SeAH Special Steel, Republic of Korea). The IN718 powders were fabricated using a gas atomizer (Hot Gas Atomization System, PSI Ltd., UK) 48 , 49 , 59 . For the gas atomization process, 2.0 kg of IN718 ingot was melted in a graphite crucible heated to 1600 °C for 30 min.…”

“…The amount of each element initially present in the IN718 powders was measured using inductively coupled plasma–atomic emission spectroscopy (ICP–AES, Optima 7300DV, PerkinElmer, USA). The concentration of oxygen and nitrogen in the IN718 (and in the BN nanosheets) was determined using an O/N analyzer (ON–900, Eltra GmbH, Germany) 48 , 49 , 59 . The density of the samples was measured using the Archimedes method.…”

Improved electrical and thermo-mechanical properties of a MWCNT/In–Sn–Bi composite solder reflowing on a flexible PET substrate

“…An X-ray photoelectron spectrometer (XPS, Quantera SXM, ULVAC–PHI, Japan) and XPSPEAK 4.1 software were used to obtain more detailed information about the composition of the compounds in the composite solder. The weight percent of the oxygen and carbon contained in the composite solder nanostructures were determined using an oxygen/nitrogen analyzer (ON–900, ELTRA GmbH, Germany) and a carbon/sulfur analyzer (CS–800, ELTRA GmbH, Germany) with 0.01 ppm sensitivity and ± 0.1 ppm accuracy for a 1.0 g sample, respectively 2 , 46 . A four-point probe (FPP–RS8, Dasol Engineering, South Korea) was used to measure the electrical resistivity of the cross-section of the composite solder.…”