Steering Photooxidation of Methane to Formic Acid over A Priori Screened Supported Catalysts
Yuheng Jiang, Yingying Fan, Xiaolong Liu, Jun Xie, Siyang Li, Kefu Huang, Xiaoyu Fan, Chang Long, Lulu Zuo, Wenshi Zhao, Xu Zhang, Juehan Sun, Peng Xu, Jiong Li, Fan Dong, Ting Tan, Zhiyong Tang
Abstract
Efficient methane photooxidation to formic acid (HCOOH) has emerged as a sustainable approach to simultaneously generate value-added chemicals and harness renewable energy. However, the persistent challenge lies in achieving a high yield and selectivity for HCOOH formation, primarily due to the complexities associated with modulating intermediate conversion and desorption after methane activation. In this study, we employ first-principles calculations as a comprehensive guiding tool and discover that by precisely controlling the O 2 activation process on noble metal cocatalysts and the adsorption strength of carbon-containing intermediates on metal oxide supports, one can finely tune the selectivity of methane photooxidation products. Specifically, a bifunctional catalyst comprising Pd nanoparticles and monoclinic WO 3 (Pd/WO 3 ) would possess optimal O 2 activation kinetics and an intermediate oxidation/desorption barrier, thereby promoting HCOOH formation. As evidenced by experiments, the Pd/WO 3 catalyst achieves an exceptional HCOOH yield of 4.67 mmol g cat –1 h –1 with a high selectivity of 62% under full-spectrum light irradiation at room temperature using molecular O 2 . Notably, these results significantly outperform the state-of-the-art photocatalytic systems operated under identical condition.