H<sub>2</sub> Reduction-Mediated Reaction Pathway Switching in Bimetallic Pt–WO<sub><i>x</i></sub> Catalysts: Shifting Fatty Acid Deoxygenation from Decarboxylation to Decarbonylation
Chao Chen, Gaobo Lin, Wenhua Zhou, Houhong Song, Liang Yin, Wei Zhao, Jing Li, Weiyu Song, Jianghao Wang, Bolong Li, Zhenyu Zhang, Jie Fu
Abstract
The decarbonylation of fatty acids represents a promising route for producing value-added alkenes; however, the thermodynamic preference for decarboxylation over decarbonylation poses a fundamental challenge. Herein, we developed a hydrogen-reducible PtWO x /SiO 2 bimetallic catalyst that enables pathway switching from predominant decarboxylation to selective decarbonylation. The PtWO x /SiO 2 –Air catalyst calcined in air exhibited outstanding fatty acid decarboxylation performance, achieving 99% stearic acid conversion and 85% heptadecane selectivity. In contrast, the hydrogen-reduced PtWO x /SiO 2 –H 2 catalyst shifted the deoxygenation pathway of stearic acid from decarboxylation to decarbonylation, increasing the selectivity for heptadecene from 5.9 to 57.1%. Structural characterization revealed that Pt nanoparticles were surrounded by amorphous WO x domains, creating abundant Pt–WO x interfaces that strengthened fatty acid adsorption. X-ray photoelectron spectroscopy (XPS) and CO–DRIFTS showed that hydrogen reduction converted PtO 2 /WO x to Pt/WO x, while presenting a strong metal–support interaction (SMSI) between Pt and WO x, inducing electron transfer from Pt to W and generating Pt δ+ . These Pt δ+ sites weakened the d-2π* back-donation effect and lowered the CO adsorption energy, thereby promoting decarbonylation. Density functional theory (DFT) calculations further confirmed that the higher binding energy barriers for C 3 H 7 * and H* in Pt/WO x, along with the lower desorption energy barriers for CO, favored the decarbonylation pathway. This work provides a catalyst design strategy with electronic modulation to overcome the thermodynamic limitations of fatty acid decarbonylation.