Oxygen Vacancy Induced Strong Metal-Support Interactions on Ni/Ce0.8Zr0.2O2 Nanorod Catalysts for Promoting Steam Reforming of Toluene: Experimental and Computational Studies

Feng Lin; Zezhi Chen; Huijuan Gong; Xiaoshu Wang; Lu Chen; Huiqiang Yu

doi:10.1021/acs.langmuir.3c00195

Oxygen Vacancy Induced Strong Metal-Support Interactions on Ni/Ce_0.8Zr_0.2O₂ Nanorod Catalysts for Promoting Steam Reforming of Toluene: Experimental and Computational Studies

Langmuir. 2023 Mar 28;39(12):4495-4506. doi: 10.1021/acs.langmuir.3c00195. Epub 2023 Mar 16.

Authors

Feng Lin¹, Zezhi Chen¹, Huijuan Gong^{1

2}, Xiaoshu Wang², Lu Chen², Huiqiang Yu²

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, PR China.
² Center of Materials Analysis, Nanjing University, Nanjing 210093, PR China.

PMID: 36926903
DOI: 10.1021/acs.langmuir.3c00195

Abstract

To develop an efficient Ni-based steam reforming catalyst for tar removal from the products of biomass gasification, Ni/Ce_0.8Zr_0.2O₂ nanorods were designed. The Ni/Ce_0.8Zr_0.2O₂ nanorod was used as a catalyst in steam reforming of toluene, which was regarded as a model compound of biomass gasification tar. At gas hourly space velocity (GHSV) of 24,000 h^-1 and Ni loading of 5 wt %, the 5Ni/Ce_0.8Zr_0.2O₂ nanorod catalyst achieved 100% of toluene conversion at 600 °C. After 10 h of operation, toluene conversion still reached 87.6%, and the carbon deposition rate was only 1.9 mg/g_cat h^-1. The experimental results demonstrated that the 5Ni/Ce_0.8Zr_0.2O₂ nanorod catalyst showed much higher catalytic activity and coking resistance than other Ni-based catalysts reported in the literature. Through different characterization technologies and density functional theory calculations, it was confirmed that the excellent catalytic performance was attributed to the strong metal-support interaction (SMSI) between Ni and the {100} facet of Ce_0.8Zr_0.2O₂. The special surface structure of {100} allowed Ni atoms to anchor to the surface oxygen vacancies and maintained its reduced state by electron transport between surface atoms. The anchored Ni facilitated oxygen vacancies formation and H₂O dissociation on the support, while the support modulated the electronic structure of Ni, which promoted its ability to toluene activation.