LaNiO3 Perovskite Synthesis through the EDTA–Citrate Complexing Method and Its Application to CO Oxidation

A series of LaNiO3 materials were synthesized by the EDTA–citrate complexing method, modifying different physicochemical conditions. The LaNiO3 samples were calcined between 600 and 800 °C and characterized by XRD, SEM, XPS, CO-TPD, TG, DT, and N2 adsorption. The results evidence that although all the samples presented the same crystal phase, LaNiO3 as expected, some microstructural and superficial features varied as a function of the calcination temperature. Then, LaNiO3 samples were tested as catalysts of the CO oxidation process, a reaction never thoroughly analyzed employing this material. The catalytic results showed that LaNiO3 samples calcined at temperatures of 600 and 700 °C reached complete CO conversions at ~240 °C, while the sample thermally treated at 800 °C only achieved a 100% of CO conversion at temperatures higher than 300 °C. DRIFTS and XRD were used for studying the reaction mechanism and the catalysts’ structural stability, respectively. Finally, the obtained results were compared with different Ni-containing materials used in the same catalytic process, establishing that LaNiO3 has adequate properties for the CO oxidation process.

Copper(II) tetrakis(pentafluorophenyl)porphyrin: Highly Active Copper-based Molecular Catalyst for Electrochemical CO2 Reduction

We report a highly active copper-based catalyst for electrochemical CO2 reduction. Electrochemical analysis revealed that the maximum turnover frequency for CO2 to CO conversion reached to 1,460,000 s-1 at an...

Resolving Local Reaction Environment toward an Optimized CO2-to-CO Conversion Performance

The local reaction environment, especially the electrode-electrolyte interface and the relevant hydrodynamic boundary layer in the vicinity of cathode, plays a vital role in defining the activity and selectivity of...

Validation of a Fixed Bed Reactor Model for Dimethyl Ether Synthesis Using Pilot-Scale Plant Data

The one-dimensional (1D) mathematical model of fixed bed reactor was developed for dimethyl ether (DME) synthesis at pilot-scale (capacity: 25–28 Nm3/h of syngas). The reaction rate, heat, and mass transfer equations were correlated with the effectiveness factor. The simulation results, including the temperature profile, CO conversion, DME selectivity, and DME yield of the outlet, were validated with experimental data. The average error ratios were below 9.3%, 8.1%, 7.8%, and 3.5% for the temperature of the reactor, CO conversion, DME selectivity, and DME yield, respectively. The sensitivity analysis of flow rate, feed pressure, H2:CO ratio, and CO2 mole fraction was investigated to demonstrate the applicability of this model.

Biofuel production over Fischer-Tropsch synthesis: effect of Fe-Co/meso-HZSM-5 catalyst weight on product composition and process conversion

Fischer-Tropsch Synthesis (FTS) using Fe-Co/meso-HZSM-5 catalyst has been investigated. The impregnated iron and cobalt on HZSM-5 could be used as bifunction catalyst which combined polimerizing synthesis gas and long hydrocarbon cracking for making biofuel (saturated C5–C25 hydrocarbons as gasoline, kerosene and diesel oil). The study emphasized the effect of catalyst weight on product composition and process conversion. The HZSM-5, had been converted from ammonium ZSM-5 through calcination, and then desilicated with NaOH solution. The Co(NO3)2.6H2O and Fe(NO3)3.9H2O were used as precursor for incipient wetness impregnation (IWI) on amorphous meso-HZSM-5. The catalyst consisted of 10 % Fe and 90 % Co by weight, called 10Fe-90Co/meso-HZSM-5. All catalysts were reduced in situ in the continuous reactor with flowing hydrogen at 25 mL/min, 1 bar, 400 °C for 10 hours. The catalyst performance was observed in the same continuous fixed bed reactor at 25 mL/min synthesis gas (30 % CO, 60 % H2, 10 % N2), 250 °C, 20 bar for 96 hours. Various catalyst weight (1, 1.2, 1.4, 1.6 gram) were applied in FTS. The desilicated HZSM-5 properties (BET analysis) were 6.1–29.9 nm mesoporous diameter, 0.3496 cc/g average mesoporous volume, 526.035 cc/g pore surface area, and the EDX analysis gave 22.1059 Si/Al ratio and 16.11 % loading (by weight) on meso-HZSM-5. The reduced catalyst showed the XRD spectra of Fe (66°), Fe-Co alloy (44.50°) and Co3O4 (36.80°). The reaction using 1 gram of 10Fe-90Co/meso-HZSM-5 catalyst produced the largest composition and conversion. The 1 gram catalyst gave the largest normal selectivity of gasoline (19.15 %) and kerosene (55.18 %). While the largest normal diesel oil selectivity (24.17 %) was obtained from 1.4 gram of catalyst. The CO conversion per gram of catalyst showed similar value (CO conversion of 26–28 %) for all catalyst weight

Electronic regulation of Ni single atom by confined Ni nanoparticles for fast and energy-efficient CO2 electroreduction

Electrocatalytic CO2 to CO conversion is approaching the industrial benchmark. Currently, Au electrodes show the best performance, whereas non-precious metal catalysts exhibit inferior activity. Here we show a densely populated Ni single-atom on nanoparticle catalyst (NiSA/NP) via direct solid-sate pyrolysis, where Ni nanoparticles donate electrons to Ni(i)-N-C sites via carbon nanotubes network, achieves a high CO current of 352 mA cm−2 at -0.55 V vs RHE in an alkaline flow cell. When coupled with a NiFe-based oxygen evolution anode into a zero-gap membrane electrolyser, it delivers an industrial-relevant CO current of 310 mA cm−2 at a low cell voltage of -2.3 V, corresponding to an overall energy efficiency of 57%. The superior CO2 electroreduction performance is attributed to the enhanced adsorption of key intermediate COOH* on electron-rich Ni single atom, together with the dense active sites.