Weak-Field Electro-Flash Induced Asymmetric Catalytic Sites toward Efficient Solar Hydrogen Peroxide Production
Fangshuai Chen, Ximeng Lv, Haozhen Wang, Fan Wen, Liangti Qu, Gengfeng Zheng, Qing Han
Abstract
High Resolution Image Download MS PowerPoint Slide 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 O 2 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 O 2 to H 2 O 2, over 4-fold higher than that of the traditional calcined BCN analogue and superior to the metal-free C 3 N 4 -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.