Fast Photocatalytic Hydrogen Peroxide Generation by Singlet Oxygen-Engaged Sequential Excitation Energy and Electron-Transfer Process
Xiangkang Zeng, Tianyi Wang, Zhuyuan Wang, Mike Tebyetekerwa, Yue Liu, Zhuoyue Liu, Gen Wang, Ary Anggara Wibowo, Gregory K. Pierens, Qinfen Gu, Xiwang Zhang
Abstract
Sequential excitation energy and electron transfer (ET) are ubiquitous pathways for converting solar energy to chemical energy in photosynthesis. Mimicking this unique process for chemical synthesis is promising yet still a big challenge. Herein, taking photosynthesis as an inspiration, we demonstrate an interesting pathway for oxygen reduction to hydrogen peroxide (H 2 O 2 ), an important and valuable commodity chemical. The proposed route was verified on a biomimetic photocatalyst, i.e., an aluminum porphyrin metal–organic framework nanosheet (Al–TCPP). Experimental investigations and theoretical calculations reveal that the dioxygen molecule is first converted to a highly active singlet oxygen intermediate through an excitation energy transfer (EET) and then reduced to H 2 O 2 via the photogenerated electrons with a reduced barrier over Al–TCPP. Consequently, Al–TCPP shows a 32 times higher H 2 O 2 evolution rate than that of the pristine TCPP counterpart, wherein excitation energy transfer mainly exists. This study presents a paradigm to mimic the photosynthetic sequential excitation energy and electron-transfer process for improved synthesis of valuable commodity chemicals.