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

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-mTiO(2) 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-mTiO(2) 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 mu mol g(cat)(-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-mTiO(2) 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 mu g mg(cat)(-1) h(-1) is accomplished at -0.6 V vs RHE. The robustness and superior activity of Ag/PW12/Zr-mTiO(2) in both photo- and electro-driven processes may offer an opportunity for effectively utilizing sunlight.

Automated summary

Driven by solar power, the synthesis of Ag/PW12/Zr-mTiO(2) composite material using doping and interface engineering principles has led to enhanced nitrogen chemisorption and ammonia production. The Zr-doping improves nitrogen adsorption, while Ag NPs decoration enhances visible light absorption, ultimately achieving high efficiency in nitrogen fixation and ammonia production.