Au/UiO-66-Zr nanohybrids: boosting the yield rates of electrochemical ammonia synthesis with the sacrificial effects of faradaic efficiencies

This work has developed two series of catalysts for nitrogen reduction reaction (NRR), i.e., xAu/UiO-66-NaBH4 and xAu/UiO-66-N2H4 nanohybrids, where UiO-66-Zr is loaded with Au nanoparticles. NH3 yield rates (rNH3) are greatly boosted owing to the sacrificial effects of a few faradaic efficiencies (FEs), which is due to different influences of the loaded Au or closely-related lost-linker defects on the electrochemically active surface areas and charge transfer efficiencies and further on rNH3 and FEs, respectively. The optimal 5Au/UiO-66-NaBH4 has a high rNH3 of & SIM;163.33 & mu;g mgcat-1 h-1 but only a moderate FE of & SIM;55.52% due to the sacrificial effects of FEs. Furthermore, the loading features of Au nanoparticles and the structures of UiO-66-Zr supports in xAu/UiO-66-NaBH4 are more favourable than those for xAu/UiO-66-N2H4 because NaBH4 is a stronger reducing agent and a more powerful destroyer of UiO-66-Zr supports in comparison with N2H4 & BULL;H2O, which endow them the generally higher rNH3 and higher FE. NH3 yield rates are boosted with the sacrificial of a few faradaic efficiencies (FEs). The even & dense loading of small Au nanoparticles on UiO-66-Zr due to NaBH4 bring the optimal yield rate but a moderate FE due to the sacrificial effects of FEs.

Automated summary

This study has developed two series of catalysts, xAu/UiO-66-NaBH4 and xAu/UiO-66-N2H4 nanohybrids, for nitrogen reduction reaction (NRR). The sacrificial effects of a few faradaic efficiencies (FEs) greatly enhance the NH3 yield rates (rNH3), which are influenced by the loaded Au or lost-linker defects on the electrochemically active surface areas and charge transfer efficiencies. The optimal 5Au/UiO-66-NaBH4 exhibits a high rNH3 of approximately 163.33 μg mgcat-1 h-1 but only a moderate FE of approximately 55.52% due to the sacrificial effects of FEs.