Fabricating Ag/PW₁₂/Zr‐mTiO₂ Composite via Doping and Interface Engineering: An Efficient Catalyst with Bifunctionality in Photo‐ and Electro‐Driven Nitrogen Reduction Reactions

Abstract

Driven by solar power and derived electricity, ambient photo‐ and electrochemical nitrogen fixations are considered promising strategies to produce low‐concentration NH3/NH4+. Under the principles of doping and interface engineering, a Ag/PW12/Zr‐mTiO2 composite is fabricated in a one‐pot synthesis, where zirconium‐doped mesoporous TiO2 is co‐decorated with silver nanoparticles (Ag NPs, optimal 1 wt%) and phosphotungstic acid (PW12, optimal 10 wt%). Enhanced nitrogen chemisorption is achieved owing to Zr‐doping, where the mesoporous structure of Zr‐mTiO2 favors nitrogen mass transfer. Ag NPs decoration leads to visible light absorption. At the interface, PW12 and Ag NPs decelerate the recombination of photo‐generated charge carriers. A Z‐scheme mechanism is suggested for the hetero‐junction, and the surface plasmon resonance effect of Ag NPs is considered in the composite. Consequently, a NH3/NH4+ production rate of 324.2 µmol gcat−1 h−1 is achieved in the photo‐driven process, together with the structure‐reactivity relationship between transient photocurrent intensity and catalytic efficiency. Moreover, constructing Ag/PW12/Zr‐mTiO2 heterojunction introduces a plentitude of active sites for the electrochemical process, together with enhanced charge transfer efficiency at the interface. Hence, an excellent NH3/NH4+ production rate of 55.0 µg mgcat−1 h−1 is accomplished at −0.6 V vs RHE. The robustness and superior activity of Ag/PW12/Zr‐mTiO2 in both photo‐ and electro‐driven processes may offer an opportunity for effectively utilizing sunlight.

Recent advances in polyoxometalate-based materials and their derivatives for electrocatalysis and energy storage

“…16d that the FeCoMOF-P 2 W 18 catalyst exhibited the highest NH 3 yield rate (47.04 μg h −1 ) and FE (31.76%) as compared to other Fe x Co y MOF-P 2 W 18 . Feng et al 170 fabricated an Ag/PW 12 /Zr–mTiO 2 composite with a mesoporous structure through one-pot synthesis (Fig. 16e), which showed superior activity in photo- and electro-driven NRR.…”

Research Progress and Perspectives on Active Sites of Photo- and Electrocatalytic Nitrogen Reduction

“…In 1977, Schrauzer and Guth opened a new chapter in photocatalytic nitrogen reduction by utilizing TiO 2 − under UV light because of its low cost and excellent stability, but the low utilization rate of photocarriers limited its application. Since then, researchers have developed a series of photocatalysts with excellent performance such as polymeric carbon nitride (PCN), , BiOX, , metal oxides, and layered double hydroxide , for N 2 fixation.…”

Enhancement of the properties of ZnAl-LDHs for photocatalytic nitrogen reduction reaction by controlling anion intercalation

“…The photocatalytic nitrogen reduction (PNR) reaction, based on the characteristics of semiconductor materials to generate photoelectrons under illumination, is considered as a green and renewable nitrogen fixation method instead of the Haber-Bosch process, which has attained widespread attention in recent years. 1,2 Although noble metal catalysts (such as Ag, 3,4 Au, 5,6 Pt, 7 etc.) exhibit excellent catalytic performance, their high price increases the cost of industrial production.…”