posted on 2018-06-15, 00:00authored byJianhua Yang, Yanzhen Guo, Ruibin Jiang, Feng Qin, Han Zhang, Wenzheng Lu, Jianfang Wang, Jimmy C. Yu
The
fixation of atmospheric N2 to NH3 is
an essential process for sustaining life. One grand challenge
is to develop efficient catalysts to photofix N2 under
ambient conditions. Herein we report an all-inorganic catalyst, Au
nanocrystals anchored on ultrathin TiO2 nanosheets with
oxygen vacancies. It can accomplish photodriven N2 fixation
in the “working-in-tandem” pathway at room temperature
and atmospheric pressure. The oxygen vacancies on the TiO2 nanosheets chemisorb and activate N2 molecules, which
are subsequently reduced to NH3 by hot electrons generated
from plasmon excitation of the Au nanocrystals. The apparent quantum
efficiency of 0.82% at 550 nm for the conversion of incident photons
to NH3 is higher than those reported so far. Optimizing
the absorption across the overall visible range with the mixture of
Au nanospheres and nanorods further enhances the N2 photofixation
rate by 66.2% in comparison with Au nanospheres used alone. This work
offers a new approach for the rational design of efficient catalysts
toward sustainable N2 fixation through a less energy-demanding
photochemical process compared to the industrial Haber–Bosch
process.