Ti₂O₃ Nanoparticles with Ti³⁺ Sites toward Efficient NH₃ Electrosynthesis under Ambient Conditions

Abstract

Electrocatalytic nitrogen reduction reaction (NRR) enabled by introducing Ti 3+ defect sites into TiO 2 through a doping strategy has recently attracted widespread attention. However, the amount of Ti 3+ ions is limited due to the low concentration of dopants. Herein, we propose Ti 2 O 3 nanoparticles as a pure Ti 3+ system that performs efficiently toward NH 3 electrosynthesis under ambient conditions. This work has suggested that Ti 3+ ions, as the main catalytically active sites, significantly increase the NRR activity. In an acidic electrolyte, Ti 2 O 3 achieves extraordinary performance with a high NH 3 yield and a Faradaic efficiency of 26.01 μg h −1 mg −1 cat. and 9.16%, respectively, which are superior to most titanium-based NRR catalysts recently reported. Significantly, it also demonstrates a stable NH 3 yield in five consecutive cycles. Theoretical calculations uncovered that the enhanced electrocatalytic activity of Ti 2 O 3 originated from Ti 3+ active sites and significantly lowered the overpotential of the potential-determining step.

Recent advances in MoS2-based materials for electrocatalysis

“…Compared to the industrial Haber–Bosch process, using catalysts and renewable electricity to drive electrochemical nitrogen fixation provides a new strategy for ammonia production under ambient conditions. 150–152 There are two common parameters used to evaluate whether the catalysts are efficient or have higher activity, namely faradaic efficiency (FE) and NH 3 yield rate ( V NH 3 ). Faradaic efficiency reflects the selectivity of products in the ammonia synthesis process.…”

Nitrogen reduction reaction under ambient conditions by K3Ti8O17 nanorod electrocatalyst

“…23–27 Recently, defect engineered TiO 2 , which is abundant and nontoxic, is established as an efficient catalyst towards NRR and has gained increasing attention in the artificial N 2 fixation process. 28–31 Nonetheless, most of the reported catalysts so far in this category could not deliver a promising yield and FE in acidic conditions. Recently, K 2 Ti 4 O 9 nanobelts, reported by Wu et al , attained 22.88 μg h −1 mg cat −1 yields and 5.87% FE at −0.5 V versus reversible hydrogen electrode in 0.1 M KOH.…”

Ambient electrochemical N2-to-NH3 conversion catalyzed by TiO2 decorated juncus effusus-derived carbon microtubes

“…Attentions have thus focused on designing and developing earth-abundant alternatives. [18][19][20][21] TiO 2 with non-toxicity, natural abundance, and high chemical stability has been widely used in sensing, 22 energy storage/ conversion, [23][24][25] and catalysis. 26,27 We found that TiO 2 nanosheets array is an active NRR catalyst but suffers from inferior conductivity.…”