Advancing the Frontiers in Nanocatalysis, Biointerfaces, and Renewable Energy Conversion by Innovations of Surface Techniques

Abstract

The challenge of chemistry in the 21 st century is to achieve 100% selectivity of the desired product molecule in multi-path reactions (green chemistry) and develop renewable energy based processes. Surface chemistry and catalysis play key roles in this enterprise. Development of in-situ surface techniques such as high pressure scanning tunneling microscopy (STM), sum frequency generation (SFG) vibrational spectroscopy, time-resolved Fourier Transform Infrared (FT-IR) methods and ambient pressure X-ray photoelectron spectroscopy (AP-XPS) enabled the rapid advancing of three fields; nanocatalysts, biointerfaces, and renewable energy conversion chemistry. In materials nanoscience, synthetic methods have been developed to produce monodisperse metal and oxide nanoparticles (NP) in the 0.8 -10 nm range with controlled shape, oxidation states, and composition, which can be used as selective catalysts since chemical selectivity appears to be dependent on all of these experimental parameters. New spectroscopic and microscopic techniques have been developed that operate under reaction conditions and reveal the dynamic change of molecular structure of catalysts and adsorbed molecules as the reactions proceed with changes in reaction intermediates, catalyst composition, and oxidation states. SFG vibrational spectroscopy detects amino acids, peptides and proteins adsorbed at hydrophobic and hydrophilic interfaces and monitors the change of surface structure and interactions with coadsorbed water. Exothermic reactions and photons generate hot electrons in metal nanoparticles that may be utilized in chemical energy conversion. The photo-splitting of water and carbon dioxide that are important research directions in renewable energy conversion is discussed.2

The surface chemistry of nanocrystalline MgO catalysts for FAME production: An in situ XPS study of H2O, CH3OH and CH3OAc adsorption

“…[19,20] Technical advances in catalyst and reactor design underpin the current and future utilisation of inedible biomass feedstocks, and are essential for biodiesel to remain a key player in the renewable energy sector for the foreseeable future. The utility of solid base catalysts for biodiesel production has been widely reported [7,12,[21][22][23], wherein they offer improved process efficiency by eliminating the need for quenching steps, and permit continuous operation.…”

Nanocrystal bilayer for tandem catalysis

“…Metal nanocrystals with well-controlled shape and size are interesting materials for catalyst design from both electronic structure and surface structure aspects. 3,4,5 From the electronic structure point of view, small metal nanoclusters have size-dependent electronic states, which make them fundamentally different from the bulk. From the surface structure point of view, the shaped nanocrystals have surfaces with well-defined atomic arrangements.…”

Size Effect of Ruthenium Nanoparticles in Catalytic Carbon Monoxide Oxidation

“…Recent progress in nanoscience, particularly in colloidal synthetic methods, has enabled the synthesis of metal NPs with precisely controlled size, shape, and composition from which new 2-dimensional (2D) and 3D NP-based model catalysts have been constructed for rational investigations of catalytic activity and selectivity. [20][21][22][23][24] In this contribution, we present a particle size effect in CO oxidation over Ru NP catalysts. Uniform Ru NPs with a controlled size from 2 to 6 nm were synthesized by colloidal synthesis and were deposited on a silicon wafer to produce 2D arrays of Ru NPs.…”