skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Direct Single-Enzyme Biomineralization of Catalytically Active Ceria and Ceria–Zirconia Nanocrystals

Abstract

Biomineralization is an intriguing approach to the synthesis of functional inorganic materials for energy applications whereby biological systems are engineered to mineralize inorganic materials and control their structure over multiple length scales under mild reaction conditions. Herein we demonstrate a single-enzyme-mediated biomineralization route to synthesize crystalline, catalytically active, quantum-confined ceria (CeO2–x) and ceria–zirconia (Ce1–yZryO2–x) nanocrystals for application as environmental catalysts. In contrast to typical anthropogenic synthesis routes, the crystalline oxide nanoparticles are formed at room temperature from an otherwise inert aqueous solution without the addition of a precipitant or additional reactant. An engineered form of silicatein, rCeSi, as a single enzyme not only catalyzes the direct biomineralization of the nanocrystalline oxides but also serves as a templating agent to control their morphological structure. The biomineralized nanocrystals of less than 3 nm in diameter are catalytically active toward carbon monoxide oxidation following an oxidative annealing step to remove carbonaceous residue. The introduction of zirconia into the nanocrystals leads to an increase in Ce(III) concentration, associated catalytic activity, and the thermal stability of the nanocrystals.

Authors:
; ORCiD logo; ; ; ; ORCiD logo
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1368336
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Nano; Journal Volume: 11; Journal Issue: 3
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; biomineralization; catalysis; ceria; ceria−zirconia; CO oxidation; nanoparticle; solid solution

Citation Formats

Curran, Christopher D., Lu, Li, Jia, Yue, Kiely, Christopher J., Berger, Bryan W., and McIntosh, Steven. Direct Single-Enzyme Biomineralization of Catalytically Active Ceria and Ceria–Zirconia Nanocrystals. United States: N. p., 2017. Web. doi:10.1021/acsnano.7b00696.
Curran, Christopher D., Lu, Li, Jia, Yue, Kiely, Christopher J., Berger, Bryan W., & McIntosh, Steven. Direct Single-Enzyme Biomineralization of Catalytically Active Ceria and Ceria–Zirconia Nanocrystals. United States. doi:10.1021/acsnano.7b00696.
Curran, Christopher D., Lu, Li, Jia, Yue, Kiely, Christopher J., Berger, Bryan W., and McIntosh, Steven. Tue . "Direct Single-Enzyme Biomineralization of Catalytically Active Ceria and Ceria–Zirconia Nanocrystals". United States. doi:10.1021/acsnano.7b00696.
@article{osti_1368336,
title = {Direct Single-Enzyme Biomineralization of Catalytically Active Ceria and Ceria–Zirconia Nanocrystals},
author = {Curran, Christopher D. and Lu, Li and Jia, Yue and Kiely, Christopher J. and Berger, Bryan W. and McIntosh, Steven},
abstractNote = {Biomineralization is an intriguing approach to the synthesis of functional inorganic materials for energy applications whereby biological systems are engineered to mineralize inorganic materials and control their structure over multiple length scales under mild reaction conditions. Herein we demonstrate a single-enzyme-mediated biomineralization route to synthesize crystalline, catalytically active, quantum-confined ceria (CeO2–x) and ceria–zirconia (Ce1–yZryO2–x) nanocrystals for application as environmental catalysts. In contrast to typical anthropogenic synthesis routes, the crystalline oxide nanoparticles are formed at room temperature from an otherwise inert aqueous solution without the addition of a precipitant or additional reactant. An engineered form of silicatein, rCeSi, as a single enzyme not only catalyzes the direct biomineralization of the nanocrystalline oxides but also serves as a templating agent to control their morphological structure. The biomineralized nanocrystals of less than 3 nm in diameter are catalytically active toward carbon monoxide oxidation following an oxidative annealing step to remove carbonaceous residue. The introduction of zirconia into the nanocrystals leads to an increase in Ce(III) concentration, associated catalytic activity, and the thermal stability of the nanocrystals.},
doi = {10.1021/acsnano.7b00696},
journal = {ACS Nano},
number = 3,
volume = 11,
place = {United States},
year = {Tue Feb 21 00:00:00 EST 2017},
month = {Tue Feb 21 00:00:00 EST 2017}
}
  • Practical applications require the production and usage of metallic nanocrystals (NCs) in large ensembles. Besides, due to their cluster-bulk solid duality, metallic NCs exhibit a large degree of structural diversity. This poses the question as to what atomic-scale basis is to be used when the structure–function relationship for metallic NCs is to be quantified precisely. In this paper, we address the question by studying bi-functional Fe core-Pt skin type NCs optimized for practical applications. In particular, the cluster-like Fe core and skin-like Pt surface of the NCs exhibit superparamagnetic properties and a superb catalytic activity for the oxygen reduction reaction,more » respectively. We determine the atomic-scale structure of the NCs by non-traditional resonant high-energy X-ray diffraction coupled to atomic pair distribution function analysis. Using the experimental structure data we explain the observed magnetic and catalytic behavior of the NCs in a quantitative manner. Lastly, we demonstrate that NC ensemble-averaged 3D positions of atoms obtained by advanced X-ray scattering techniques are a very proper basis for not only establishing but also quantifying the structure–function relationship for the increasingly complex metallic NCs explored for practical applications.« less
  • The mechanism by which the ferredoxin-thioredoxin system activates the target enzyme, NADP-malate dehydrogenase, was investigated by analyzing the sulfhydryl status of individual protein components with (/sup 14/C)iodoacetate and monobromobimane. The data indicate that ferredoxin-thioredoxin reductase (FTR)--an iron-sulfur enzyme present in oxygenic photosynthetic organisms--is the first member of a thiol chain that links light to enzyme regulation. FTR possesses a catalytically active dithiol group localized on the 13 kDa (similar) subunit, that occurs in all species investigated and accepts reducing equivalents from photoreduced ferredoxin and transfers them stoichiometrically to the disulfide form of thioredoxin m. The reduced thioredoxin m, in turn,more » reduces NADP-malate dehydrogenase, thereby converting it from an inactive (S-S) to an active (SH) form. The means by which FTR is able to combine electrons (from photoreduced ferredoxin) with protons (from the medium) to reduce its active disulfide group remains to be determined.« less
  • We studied CO oxidation on model and powder catalysts of Au-CeO 2 and Au-CeO x/TiO 2. Phenomena observed in Au-CeO 2(1 1 1) and Au-CeO 2/TiO 2(1 1 0) provided useful concepts for designing and preparing highly active and stable Au-CeO x/TiO 2 powder catalysts for CO oxidation. Small particles of Au dispersed on CeO 2(1 1 1) displayed high catalytic activity, making Au-CeO 2(1 1 1) a better CO oxidation catalyst than Au-TiO 2(1 1 0) or Au-MgO(1 0 0). An excellent support for gold was found after depositing nanoparticles of ceria on TiO 2(1 1 0). The CeOmore » x nanoparticles act as nucleation centers for gold, improving dispersion of the supported metal and helping in the creation of reaction sites efficient for the adsorption of CO and the dissociation of the O 2 molecule. High-surface area catalysts were prepared by depositing gold on ceria nanorods and CeO x/TiO 2 powders. The samples were tested for the low-temperature (10–70 °C) oxygen-rich (1%CO/4%O 2/He) CO oxidation reaction after pre-oxidation (20%O 2/He, 300 °C) and pre-reduction (5%H 2/He, 300 °C) treatments. Moreover, synchrotron-based operando X-ray diffraction (XRD) and X-ray absorption (XAS) spectroscopy were used to study the Au-CeO 2 and Au-CeOx/TiO 2 catalysts under reaction conditions. Our operando findings indicate that the most active phase of these catalysts for low-temperature CO oxidation consist of small particles of metallic Au dispersed on CeO 2 or CeO x/TiO 2.« less
  • Cited by 17
  • Nanometer-sized particles ranging from 2 to 3 nm of CeO{sub 2} (ceria)-ZrO{sub 2} (zirconia) solid solutions with cubic and/or tetragonal fluorite-type structure in the wide composition range from 20 to 100 mol% CeO{sub 2}, without a trace of monoclinic ZrO{sub 2} phase, could be directly synthesized at low temperature of 100 C from acidic aqueous solutions of ZrOCl{sub 2} and (NH{sub 4}){sub 2}Ce(NO{sub 3}){sub 6} by forced simultaneous hydrolysis, i.e., ''forced cohydrolysis.'' Analytical values of CeO{sub 2}/ZrO{sub 2} ratio in the as-precipitated solid solutions showed fairly good agreement with starting compositions in the solutions. The proceeding of the hydrolysis andmore » formation rate of fluorite-type solid solutions tended to slow down at near median composition. Any change in crystalline phase of as-precipitated solid solutions was not observed by powder X-ray diffractometry after heat treatment in air below 1000 C. Ceria-zirconia solid solutions with fluorite structures containing large amount of ZrO{sub 2} maintained high surface area after heat treatment at 1000 C.« less