posted on 2024-03-05, 12:34authored byFangshuai Chen, Ximeng Lv, Haozhen Wang, Fan Wen, Liangti Qu, Gengfeng Zheng, Qing Han
Borocarbonitride
(BCN), in a mesoscopic asymmetric state, is regarded
as a promising photocatalyst for artificial photosynthesis. However,
BCN materials reported in the literature primarily consist of symmetric
N-[B]3 units, which generate highly spatial coupled electron–hole
pairs upon irradiation, thus kinetically suppressing the solar-to-chemical
conversion efficiency. Here, we propose a facile and fast weak-field
electro-flash strategy, with which structural symmetry breaking is
introduced on key nitrogen sites. As-obtained double-substituted BCN
(ds-BCN) possesses high-concentration asymmetric
[B]2–N-C coordination, which displays a highly separated
electron–hole state and broad visible-light harvesting, as
well as provides electron-rich N sites for O2 affinity.
Thereby, ds-BCN delivers an apparent quantum yield
of 7.6% at 400 nm and a solar-to-chemical conversion efficiency of
0.3% for selective 2e-reduction of O2 to H2O2, over 4-fold higher than that of the traditional calcined
BCN analogue and superior to the metal-free C3N4-based photocatalysts reported so far. The weak-field electro-flash
method and as-induced catalytic site symmetry-breaking methodologically
provide a new method for the fast and low-cost fabrication of efficient
nonmetallic catalysts toward solar-to-chemical conversions.