Triggering photocatalytic performance of La2CoxMn2-xO6 via heat activation

Cheng Chen; Mingge Wu; Bolei Chen; Chunyan Ma; Maoyong Song; Guibin Jiang

doi:10.1073/pnas.2310004120

Triggering photocatalytic performance of La₂Co_xMn_2-xO₆ via heat activation

Proc Natl Acad Sci U S A. 2023 Oct 31;120(44):e2310004120. doi: 10.1073/pnas.2310004120. Epub 2023 Oct 23.

Authors

Cheng Chen^{1

2

3}, Mingge Wu^{1

3}, Bolei Chen⁴, Chunyan Ma^{1

2}, Maoyong Song^{1

2

3}, Guibin Jiang^{2

3}

Affiliations

¹ Key Laboratory of Environmental Nanotechnology and Health Effects, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
² State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
³ University of Chinese Academy of Sciences, Beijing 100049, China.
⁴ Hubei Key Laboratory of Environmental and Health Effects of Persistent Toxic Substances, Jianghan University, Wuhan 430056, China.

Abstract

The La-based perovskite (LaBO₃) exhibits excellent optical properties. However, its valence band (VB) potential is not sufficiently positive to reach the oxidation potential required for the cleavage of chemical bonds (such as benzylic C-H), limiting its application in photocatalysis. Herein, we report the unconventional effects of heat activation on the reduction of the dissociation energy of benzylic C-H and aqueous H-O, thereby triggering the photocatalytic activity of La₂Co_xMn_2-xO₆ perovskites. Additionally, we demonstrate that photocatalysis is the main contributor to substrate conversion in the selective oxidation of toluene and reduction of CO₂. Particularly, La₂Co_1.5Mn_0.5O₆ shows excellent performance with a product yield of 550.00 mmol g_cat^-1 and a toluene conversion of 22,866.67 μmol g_cat^-1 h^-1. To the best of our knowledge, this is the highest reported product yield for the selective oxidation of benzylic C-H bond of toluene. Our findings provide insight into the specific role of heat activation in photocatalysis, which is crucial for breaking and overcoming the VB barrier to realize challenging reactions.

Keywords: breakthrough from scratch in photoactivity; efficient carrier separation; heat-activated photocatalysis; reduction of CO2; selective oxidation of benzylic C–H.

Abstract

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