More Like this

1. Remote controlled optical manipulation of bimetallic nanoparticle catalysts using peptides

   https://doi.org/10.1039/D1CY00189B  

   Lawrence, Randy L.; Olagunju, Mary O.; Liu, Yang; Mahalingam, Krishnamurthy; Slocik, Joseph M.; Naik, Rajesh R.; Frenkel, Anatoly I.; Knecht, Marc R. (April 2021, Catalysis Science & Technology)

   null (Ed.)

   Bimetallic nanoparticles remain a promising avenue to achieve highly reactive catalysts. In this contribution, we demonstrate the use of a photoswitchable peptide for the production of PdAu bimetallic nanoparticles at a variety of Pd : Au ratios. Using this peptide, the biomolecular overlayer structure can be switched between two different conformations ( cis vs. trans ) via light irradiation, thus accessing two different surface structures. The composition and arrangement of the materials was fully characterized, including atomic-level analyses, after which the reactivity of the bimetallic materials was explored using the reduction of 4-nitrophenol as a model system. Using these materials, it was demonstrated that the reactivity was maximized for the particles prepared at a Pd : Au ratio of 1 : 3 and with the peptide in the cis conformation. Such results present routes to a new generation of catalysts that could be remotely activated for on/off reactivity as a function of the ligand overlayer conformation. 

   more » « less
2. Peptide/Nanoparticle Biointerfaces for Multistep Tandem Catalysis

   https://doi.org/10.1021/jacs.3c04097  

   Perdomo, Yuliana; Slocik, Joseph M; Phillips, David M; Knecht, Marc R (August 2023, Journal of the American Chemical Society)

   The realization of multifunctional nanoparticle systems is essential to achieve highly efficient catalytic materials for specific applications; however, their production remains quite challenging. They are typically achieved through the incorporation of multiple inorganic components; however, incorporation of functionality could also be achieved at the organic ligand layer. In this work, we demonstrate the generation of multifunctional nanoparticle catalysts using peptide-based ligands for tandem catalytic functionality. To this end, chimeric peptides were designed that incorporated a Au binding sequence and a catalytic sequence which can drive ester hydrolysis. Using this chimera, Au nanoparticles were prepared, which sufficiently presented the catalytic domain of the peptide to drive tandem catalytic processes occurring at the peptide ligand layer and the Au nanoparticle surface. This work represents unique pathways to achieve multifunctionality from nanoparticle systems tuned by both the inorganic and bio/organic components, which could be highly important for applications beyond catalysis, including theranostics, sensing, and energy technologies. 

   more » « less
3. Identification of key active residues and solution conditions that affect peptide-catalyzed ester hydrolysis

   https://doi.org/10.1039/D4NJ00977K  

   Meerbott, Kyle B; Knecht, Marc R (April 2024, New Journal of Chemistry)

   Peptides respresent intriguing materials to achieve sustainable catalytic reactivity that mimic the natural functions of enzymes, but without the limitations of temperature/solvent sensitivity. They could also be applicable to a wide variety of substrates, thus expanding their potential use at different reaction levels ranging from the benchtop to industrial. Unfortunately, signfiicant use of catalytic peptides remains limited due to the general lack of understanding of the fundamental basis of their inherent reactivity. In this contribution, we examine the reactviity of a peptide (termed CPN3) previously isolated with ester hydrolysis reactivity. It is demonstrated that the system is most reactive under slightly basic conditions. While the system is slower than comparable enzymes, it demonstrates signficiant reactivity across multiple substrates and different reaction conditions that coud likely lead to enzymatic denaturation. In addition, key active site residues were identified to begin to elucidate the fundamental basis of the reactivity. Such results could be used to design new sequences with enhanced reactivity under sustainable conditions. 

   more » « less
4. A General Approach for Metal Nanoparticle Encapsulation Within Porous Oxides

   https://doi.org/10.1002/adma.202409710  

   Zhou, Chengshuang; Oh, Jinwon; Stone, Michael_L; Richardson, Sydney; Chung, Pin‐Hung; Osio‐Norgaard, Jorge; Nhan, Bang_T; Kumar, Abinash; Chi, Miaofang; Cargnello, Matteo (November 2024, Advanced Materials)

   Abstract Encapsulation of metal nanoparticles within oxide materials has been shown as an effective strategy to improve activity, selectivity, and stability in several catalytic applications. Several approaches have been proposed to encapsulate nanoparticles, such as forming core‐shell structures, growing ordered structures (zeolites or metal‐organic frameworks) on nanoparticles, or directly depositing support materials on nanoparticles. Here, a general nanocasting method is demonstrated that can produce diverse encapsulated metal@oxide structures with different compositions (Pt, Pd, Rh) and multiple types of oxides (Al₂O₃, Al₂O₃‐CeO₂, ZrO₂, ZnZrO_x, In₂O₃, Mn₂O₃, TiO₂) while controlling the size and dispersion of nanoparticles and the porous structure of the oxide. Metal@polymer structures are first prepared, and then the oxide precursor is infiltrated into such structures and the resulting material is calcined to form the metal@oxide structures. Most Pt@oxides catalysts show similar catalytic activity, demonstrating the availability of surface Pt sites in the encapsulated structures. However, the Pt@Mn₂O₃sample showed much higher CO oxidation activity, while also being stable under aging conditions. This work demonstrated a robust nanocasting method to synthesize metal@oxide structures, which can be utilized in catalysis to finely tune metal‐oxide interfaces. 

   more » « less
5. Atomic-precision engineering of metal nanoclusters

   https://doi.org/10.1039/d0dt01853h  

   Du, Xiangsha; Jin, Rongchao (August 2020, Dalton Transactions)

   null (Ed.)

   Ultrasmall metal nanoparticles (below 2.2 nm core diameter) start to show discrete electronic energy levels due to strong quantum confinement effects and thus behave much like molecules. The size and structure dependent quantization induces a plethora of new phenomena, including multi-band optical absorption, enhanced luminescence, single-electron magnetism, and catalytic reactivity. The exploration of such new properties is largely built on the success in unveiling the crystallographic structures of atomically precise nanoclusters (typically protected by ligands, formulated as M n L m q , where M = metal, L = Ligand, and q = charge). Correlation between the atomic structures of nanoclusters and their properties has further enabled atomic-precision engineering toward materials design. In this frontier article, we illustrate several aspects of the precise engineering of gold nanoclusters, such as the single-atom size augmenting, single-atom dislodging and doping, precise surface modification, and single-electron control for magnetism. Such precise engineering involves the nanocluster's geometric structure, surface chemistry, and electronic properties, and future endeavors will lead to new materials design rules for structure–function correlations and largely boost the applications of metal nanoclusters in optics, catalysis, magnetism, and other fields. Following the illustrations of atomic-precision engineering, we have also put forth some perspectives. We hope this frontier article will stimulate research interest in atomic-level engineering of nanoclusters. 

   more » « less