Atomic layer deposition technique refining oxygen vacancies in TiO2 passivation layer for photoelectrochemical ammonia synthesis

Photoelectrochemically (PEC) converting environmental pollutant nitrate back to valuable ammonia is a powerful complement to NH3 synthesis from Haber-Bosch process. Herein, atomic layer deposition (ALD) technique is employed to refine oxygen defect of TiO2 passivation layer on p-type silicon nanowire arrays to introduce active sites and improve the stability of silicon. Si@TiO2-50-Vo nanowire arrays photocathode delivers a greatly enhanced NH3 yield rate of 1074 mu gNH3 h-1 cm-2 and Faradaic efficiency (FE) of 94.3% at -0.6 V, as well as with excellent cycling stability. Theoretical calculations indicate that oxygen defect in passivation layer promotes the adsorption of nitrate and lowers the energy barrier of primary steps in NTRR.

Automated summary

The use of ALD technique on silicon nanowires has enhanced the production rate and efficiency of ammonia, achieving the conversion of nitrate to ammonia successfully.