Light-induced phase transformation to two-dimensional amorphous spinel CoAlOx nanosheets as a tandem photothermal catalyst for efficient and durable toluene oxidation

Abstract

Low temperature fabrication of spinel oxides and development of efficient and durable toluene photothermal catalysts remain challenging. Herein, two-dimensional amorphous spinel CoAlOx nanosheets (CoAl-LDH-L2) have been fabricated via a light-induced phase transformation strategy using intense photooxidation. Light-induced decomposition and phase transformation process have been used to elucidate the growth mechanism. The CoAl-LDH-L2 exhibits improved toluene adsorption and photothermal conversion, with the highest photothermal catalytic toluene conversion (∼100 % at 500 ppm) at 90 °C, outperforming most previously reported catalysts. Irradiation with mild external heating significantly increases the mineralization rate (∼90 %) and improves the long-term and cycling stability (∼5% losses within 39 h) relative to that under single-light-driven conditions. In-situ DRIFT spectroscopy was also performed for revealing the “tandem photothermal catalysis” mechanism for toluene conversion. This work offers a novel strategy for developing spinel oxides as low-temperature photothermal catalyst in a green and sustainable way.