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

Abstract

To develop an efficient Ni-based steam reforming catalyst for tar removal from the products of biomass gasification, Ni/Ce0.8Zr0.2O2 nanorods were designed. The Ni/Ce0.8Zr0.2O2 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/Ce0.8Zr0.2O2 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/gcat h–1. The experimental results demonstrated that the 5Ni/Ce0.8Zr0.2O2 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 Ce0.8Zr0.2O2. 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.

Hydrogenolysis of Glycerol over NiCeZr Catalyst Modified with Mg, Cu, and Sn at the Surface Level

“…The Mg/NiCeZr and Sn/NiCeZr catalysts showed a decrease in hydrogen consumption related to both O V (α-contribution) and β-contribution. The former may be attributed to the fact that O V sites could serve as anchor points for these metal oxides [ 42 ]. However, the α-contribution in the Cu/NiCeZr catalyst was similar to that of the base catalyst, as new oxygen vacancies could be formed upon Cu impregnation [ 43 ].…”

Pd Nanoparticles Supported on Ultrapure ZnO Nanopowders as Reusable Multipurpose Catalysts

“…Point defects, in particular, neutral oxygen vacancies (electron rich), provide conditions to serve not only as exceptional nucleation sites but may also boost the metal−support interaction affecting in final both, the catalyst stability and its overall activity. 43,44 In the second step, the Pd deposition on the as-prepared CVS-ZnO powder was carried out in line with the previously reported procedure. 42 Upon the addition of the reducing agent to an aqueous suspension of the Pd precursor and CVS-ZnO, a black precipitate was formed.…”

“…In line with the conditions afforded during the crystal formation, oxygen vacancies were identified to be the main defects in this type of ZnO, both on the surface and in the bulk. Point defects, in particular, neutral oxygen vacancies (electron rich), provide conditions to serve not only as exceptional nucleation sites but may also boost the metal–support interaction affecting in final both, the catalyst stability and its overall activity. , …”

Transformation of H2S in In Situ Landfill Gas Deoxygen with Pt/γ-Al2O3 as the Catalyst and Its Impact on Catalyst Activity

“…, E catalyst , and E CH 4 represent the energies of the catalyst model of CH 4 adsorbate, pristine catalyst model, and CH 4 gas molecule, respectively. 16,17 The ab initio molecular dynamics (AIMD) simulations were conducted under a constant volume and temperature (NVT) ensemble using the VASP program. The AIMD simulations were performed at 250 °C using a Nose−Hoover thermostat chain with a time step of 1 fs.…”