Enhanced Electrocatalytic N₂ Reduction via Partial Anion Substitution in Titanium Oxide–Carbon Composites

Abstract

The electrochemical conversion of N 2 at ambient conditions using renewably generated electricity is an attractive approach for sustainable ammonia (NH 3 )p roduction. Considering the chemical inertness of N 2 ,r ational design of efficient and stable catalysts is required. Therefore,i nt his work, it is demonstrated that aC -doped TiO 2 /C (C-Ti x O y /C) material derived from the metal-organic framework (MOF) MIL-125(Ti) can achieve ah igh Faradaic efficiency (FE) of 17.8 %, which even surpasses most of the established noble metal-based catalysts.O nt he basis of the experimental results and theoretical calculations,t he remarkable properties of the catalysts can be attributed to the doping of carbon atoms into oxygen vacancies (OVs) and the formation of Ti À Cb onds in C-Ti x O y .This binding motive is found to be energetically more favorable for N 2 activation compared to the non-substituted OVsi nT iO 2 .T his work elucidates that electrochemical N 2 reduction reaction (NRR) performance can be largely improved by creating catalytically active centers through rational substitution of anions into metal oxides.Asexpressed by its annual worldwide production exceeding 145 million tons,N H 3 plays an extremely important role in agricultural fertilizers,fuels,ashydrogen carrier and in many other fields. [1] Thei ndustrially applied Haber-Bosch process suffers from the need for high temperature and pressure.

Oxidation State Modulation of Bismuth for Efficient Electrocatalytic Nitrogen Reduction to Ammonia

“…[7] Therefore, a series of rigorous control experiments and 15 N isotopic labeling experiment are usually required to confirm the origin of the produced NH 3 and exclude the possible ammonia contamination. In addition, to boost the performance of electrochemical NRR at ambient conditions, much efforts have been paid designing efficient catalysts, especially transition metal-based catalysts such as Au-based catalysts, [8] Fe-based catalysts, [9] Mo-based catalysts, [10] Ti-based catalysts, [11] etc. Despite encouraging advancements have been achieved during the past few years, the NRR activity and selectivity of the transition metal-based materials are still far from satisfactory mainly because the d electrons of transition metals are prone to the formation of metal-H bond for competitive HER, leading to a low NRR selectivity and low catalytic efficiency.…”

Long‐Cycle‐Life Sodium‐Ion Battery Fabrication via a Unique Chemical Bonding Interface Mechanism

“…C(N)-Ti bonds can still be observed in H-NTO-650, while C-NTO-650 is entirely free of C(N)-Ti bonds, indicating that C (N) atoms can occupy the oxygen vacancies generated to form the NTO/C (N) interface, which has also been reported in the related literature. [24] UV-vis absorption spectra and XPS valence band spectroscopy further confirmed the enhanced electrical conductivity. The band gap energies (E g ) of all materials were also investigated by UVvis absorption spectroscopy, and it was observed that the absorption edges of A-NTO and H-NTO had shifted to 374 and 387 nm, respectively, when compared to C-NTO (Figure S16a, Supporting Information); therefore, the E g of C-NTO, A-NTO, and H-NTO were 2.89, 2.98, and 3.05 eV, respectively (Figure S16b, Supporting Information).…”

Overcoming Chemical Inertness under Ambient Conditions: A Critical View on Recent Developments in Ammonia Synthesis via Electrochemical N2 Reduction by Asking Five Questions

“…B and N co‐doped carbons with highly porous structures were synthesized with desirable NRR performance. Doped heteroatoms can successfully construct B−N bonds and possible Frustrated Lewis pairs (FLPs) from unsaturated B and N atoms, which can provide active sites for N 2 reduction …”