Modulating Oxygen Vacancies of TiO₂ Nanospheres by Mn-Doping to Boost Electrocatalytic N₂ Reduction

Abstract

Electrochemical N 2 reduction reaction (NRR) is an environmentally benign and sustainable approach for NH 3 synthesis under ambient conditions, which needs efficient electrocatalyst to meet the enormous challenge of activating the inert N 2 molecule. Recently, TiO 2 emerges as an active NRR electrocatalyst with advantages of abundance, nontoxicity, and high thermal stability. Heteroatom doping is an effective oxygen vacancy introduction strategy to manufacture unique electron and structure properties of metal oxides, which will greatly influence the catalysts' activity. In this work, we developed Mn-doped TiO 2 nanospheres (Mn-TiO 2 ) for electrochemical NRR. In 0.1 M Na 2 SO 4 , Mn-TiO 2 shows a large NH 3 yield rate of 20.05 μg h −1 mg cat.−1 and a high Faradaic efficiency of 11.93%, which are much higher than undoped TiO 2 . The mechanism of performance improvement is uncovered by density functional theory calculations.

Synthesis and Characterization of Manganese-Modified Black TiO2 Nanoparticles and Their Performance Evaluation for the Photodegradation of Phenolic Compounds from Wastewater

“…The B-TiO 2 and Mn-B-TiO 2 NPs presented two overlapping peaks at BE 529.94, and 531.37 eV, attributed to lattice oxygen and oxygen deficient region (O v ), respectively [ 43 ]. The deconvoluted O1s spectra proved that the oxygen vacancies were created by Mn doping and agreed well with previous studies [ 44 , 45 ] that reported similar results in terms of oxygen vacancy generation by Mn doping.…”

Cation Decorated Ferric Oxide with a Polyhedral‐like Structure for the Electrocatalytic Nitrogen Reduction Reaction

“…It can be seen that the Fe 2 + /Fe 3 + of 17 % V-α-Fe 2 O 3 is 2, much higher than α-Fe 2 O 3 (0.5), demonstrating that the abundant Fe 2 + that acted as the active sites for NRR were well-exposed on the surface of 17 % V-α-Fe 2 O 3 . [27,28] This might be owning to the incorporation of V cations of high valence state. Furthermore, the O 1s spectrum of 17 % V-α-Fe 2 O 3 and α-Fe 2 O 3 were provided as well as shown in Figure S2b, from which three peaks located at 533.5 eV, 531.8 eV and 529.8 eV in keeping with the adsorbed water molecules (O1), hydroxyl (O2) and metal-oxygen bonds (O3) were clearly observed in both two samples.…”

“…), [38] Mn-doped TiO 2 (20.05 μg h À 1 mg À 1 cat. ), [27] TiO 2 /Ti 3 C 2 T x (32.17 μg h À 1 mg À 1 cat. ) [11] as well as Nb 2 O 5 (43.6 μg h À 1 mg À 1 cat.…”

Synergistic Enhancement of Electrocatalytic Nitrogen Reduction Over Boron Nitride Quantum Dots Decorated Nb2CTx‐MXene

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efficient and selective catalysts, including noble metals, [16][17][18] non-noble metal compounds, [19][20][21][22][23][24][25][26][27] and metal-free materials, [28][29][30][31][32] to reduce the N 2 activation barrier and retard the HER. The catalyst NRR performance can be further optimized by various strategies, including heteroatom doping, [33][34][35][36][37][38] defect engineering, [39][40][41] and heterostructure coupling. [42][43][44][45][46] MXenes, a new family of 2D metal carbides/nitrides, have attracted considerable interest in electrocatalysis owing to their unique layered structure, excellent conductivity, high surface area, and tunable surface functionalities.

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