Phase-selective active sites on ordered/disordered titanium dioxide enable exceptional photocatalytic ammonia synthesis

Abstract

This work highlights the importance of a rational design for more energetically suitable nitrogen reduction reaction routes and mechanisms by regulating the electronic band structures with phase-selective defect sites.

Unveiling a Three Phase Mixed Heterojunction via Phase‐Selective Anchoring of Polymer for Efficient Photocatalysis

“…[ 36,53 ] The PL intensity of P25 was more quenched than that of anatase TiO 2 ( Figure 5 a) because of good charge separation in P25 by the interfaced rutile and anatase phase type II band alignment (Figure S18, Supporting Information). [ 54,55 ] This result agreed well with previous findings, [ 56–58 ] and it was also proven by Shen et al. that the photogenerated electrons in the conduction band and shallow trap states of anatase were transferred to rutile after excitation.…”

“…[36,53] The PL intensity of P25 was more quenched than that of anatase TiO 2 (Figure 5a) because of good charge separation in P25 by the interfaced rutile and anatase phase type II band alignment (Figure S18, Supporting Information). [54,55] This result agreed well with previous findings, [56][57][58] and it was also proven by Shen et al that the photogenerated electrons in the conduction band and shallow trap states of anatase were transferred to rutile after excitation. [55] The band bending at the interface of anatase and rutile TiO 2 accumulated the photo-induced electrons in the rutile phase and holes in the anatase phase, leading to effective charge separation and increased photo-induced e -/h + lifetime (Figure S19b, Supporting Information).…”

Efficient Nitrate Conversion to Ammonia on f-Block Single-Atom/Metal Oxide Heterostructure via Local Electron-Deficiency Modulation

“…The product selectivity was performed by chronoamperometry measurements operated for 1 h at different potentials, with generated NH 3 quantified by a UV−vis absorption spectrometry analysis (indophenol blue spectrophotometric method) (Figures S21−S23). 31 Compared to P/D-NiO 400 substrates, the electrophilic Gd SA coupled with defective NiO (Gd SA -D-NiO 400 ) exhibited the highest NO 3 −to-NH 3 FE of ∼97% at a much lower applied voltage of −0.1 V vs RHE with a maximum yield rate of ∼628 μg/(mg cat h) (at −0.2 V vs RHE), comparable/superior to most of the reported NitRR and NRR electrocatalysts (Figure 4b−d and Table S4). Consistent with the theoretical calculations, the significantly enhanced NH 3 yield rate of Gd SA -D-NiO 400 compared to Gd SA -P-NiO 400 validated the beneficial role of the oxygen defect sites in the D-NiO 400 toward accelerating the water dissociation process along with suppressed H* dimerization to H 2 (HER), thus transferring necessary protons for boosting the subsequent intermediate protonation steps and controlling the NitRR selectivity (Figure 4b,c and Figure S24).…”

A minireview on catalysts for photocatalytic N2 fixation to synthesize ammonia

“…Homojunction catalyst such as ordered/disordered TiO 2 exhibited a superior activity in PNF, affording a NH 3 formation rate of 432 μmol g −1 h −1 under solar illumination. 92 In the homojunction catalyst, ordered TiO 2 exhibited a stronger N 2 adsorption capacity with a reduced activation barrier while the disordered TiO 2 was rich in oxygen vacancies which selectively chemisorbed N 2 and enhanced visible light harvesting. The synergistic effect between ordered TiO 2 and disordered TiO 2 , together with the rapid interfacial charge separation, ensured its superior activity ( Fig.…”