Iron Nitride Nanoparticles for Enhanced Reductive Dechlorination of Trichloroethylene

Abstract

Nitriding has been used for decades to improve the corrosion resistance of iron and steel materials. Moreover, iron nitrides (Fe x N) have been shown to give an outstanding catalytic performance in a wide range of applications. We demonstrate that nitriding also substantially enhances the reactivity of zerovalent iron nanoparticles (nZVI) used for groundwater remediation, alongside reducing particle corrosion. Two different types of Fe x N nanoparticles were synthesized by passing gaseous NH 3 /N 2 mixtures over pristine nZVI at elevated temperatures. The resulting particles were composed mostly of face-centered cubic (γ′-Fe 4 N) and hexagonal close-packed (ε-Fe 2−3 N) arrangements. Nitriding was found to increase the particles' water contact angle and surface availability of iron in reduced forms. The two types of Fe x N nanoparticles showed a 20-and 5-fold increase in the trichloroethylene (TCE) dechlorination rate, compared to pristine nZVI, and about a 3-fold reduction in the hydrogen evolution rate. This was related to a low energy barrier of 27.0 kJ mol −1 for the first dechlorination step of TCE on the γ′-Fe 4 N(001) surface, as revealed by density functional theory calculations with an implicit solvation model. TCE dechlorination experiments with aged particles showed that the γ′-Fe 4 N nanoparticles retained high reactivity even after three months of aging. This combined theoretical-experimental study shows that Fe x N nanoparticles represent a new and potentially important tool for TCE dechlorination.

Promoting Effect of Nitride as Support for Pd Hydrodechlorination Catalyst

“…(3) The synthetic method for these oxide/nitrides has been well-documented in the literature, and TiN, CoN, VN, and Mo 2 N are also the most stable and common phases among their nitrides. 23,31,32 (4) The TiO 2 , Co 3 O 4 , V 2 O 5 , and MoO 3 showed different morphologies�nanoparticles, nanosheet, nanoflower, and nanobelt�which enables us to study the morphology effect (see infra), and (5) these TMNs that have been reported are rich in electrons, which is the core reason for our selection. 22 As the d-band center theory is a highly intuitive method to explore how electronic structures influence catalytic activity, we predicted the modulated electronic states of Pd sites on different TMNs and TMOs as well as their d-band centers.…”

“…Metal nitrides were synthesized via the nitridation of their corresponding oxides in a NH 3 atmosphere . Of note is that to testify the generality of proposed method, here, we also selected a commercially available metal oxide, P 25 TiO 2 NPs, as the processor to synthesize Ti 2 N. Specifically, 1.0 g of P 25 TiO 2 NPs, MoO 3 nanobelts, or Co 3 O 4 nanosheets was loaded into a quartz boat and placed in a tubular furnace.…”

“…Metal nitrides were synthesized via the nitridation of their corresponding oxides in a NH 3 atmosphere. 23 Of note is that to testify the generality of proposed method, here, we also selected a commercially available metal oxide, P 25 TiO 2 NPs, as the processor to synthesize Ti 2 N. Specifically, 1.0 g of P 25 TiO 2 NPs, MoO 3 nanobelts, or Co 3 O 4 nanosheets was loaded into a quartz boat and placed in a tubular furnace. Then, under a 100 mL/min NH 3 flow, the furnace temperature was increased to the desired temperatures of 800, 785, and 380 °C for the synthesis of TiN, Mo 2 N, and CoN, respectively, at a rate of 5 °C/min and duration of 8 h (for TiN and Mo 2 N) or 4 h (for CoN).…”

“…Transition metal nitrides (TMNs), a group of nonstoichiometric, interstitial compounds with large free-carrier concentrations, endow noble metal-like performances to catalysis. The M–N bonding in TMNs expands the parent metal lattice and constricts the metal d-band, , which influences the electronic state in a manner similar to noble metal but at much lower costs. Smaller d-band occupation deficiencies and higher densities of states of the metal near the Fermi level endow TMNs with noble metal-like catalytic activities.…”

Advanced Nano-biotechnology for Chlorinated Volatile Compound Pollutants Control

“…Recently, nano ZVI has become a promising strategy for the treatment of CVOCs from polluted soil and groundwater (Mdlovu et al, 2019;Galdames et al, 2020). Iron nanoparticles were found to augment the reduction reaction of trichloroethylene dechlorination (Brumovsky et al, 2022). The nanometer size enhances mobility via the porous media, and the low toxicity of nano-ZVI augments the remediation processes while preserving soil properties, allowing subsequent application of other processes, such as biological remediation, unaffected (Lefevre et al, 2016).…”