A General Approach for Metal Nanoparticle Encapsulation Within Porous Oxides.

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 (AlO, AlO-CeO, ZrO, ZnZrO, InO, MnO, TiO) while controlling the size and dispersion of nanoparticles and the porous structure of the oxide.

Unveiling the Stability of Encapsulated Pt Catalysts Using Nanocrystals and Atomic Layer Deposition.

Platinum exhibits desirable catalytic properties, but it is scarce and expensive. Optimizing its use in key applications such as emission control catalysis is important to reduce our reliance on such a rare element. Supported Pt nanoparticles (NPs) used in emission control systems deactivate over time because of particle growth in sintering processes.

Steam-Assisted Selective CO Hydrogenation to Ethanol over Ru-In Catalysts.

Multicomponent catalysts can be designed to synergistically combine reaction intermediates at interfacial active sites, but restructuring makes systematic control and understanding of such dynamics challenging. We here unveil how reducibility and mobility of indium oxide species in Ru-based catalysts crucially control the direct, selective conversion of CO to ethanol. When uncontrolled, reduced indium oxide species occupy the Ru surface, leading to deactivation.

Design and Validation of a High-Throughput Reductive Catalytic Fractionation Method.

Reductive catalytic fractionation (RCF) is a promising method to extract and depolymerize lignin from biomass, and bench-scale studies have enabled considerable progress in the past decade. RCF experiments are typically conducted in pressurized batch reactors with volumes ranging between 50 and 1000 mL, limiting the throughput of these experiments to one to six reactions per day for an individual researcher. Here, we report a high-throughput RCF (HTP-RCF) method in which batch RCF reactions are conducted in 1 mL wells machined directly into Hastelloy reactor plates.

Templated encapsulation of platinum-based catalysts promotes high-temperature stability to 1,100 °C.

Stable catalysts are essential to address energy and environmental challenges, especially for applications in harsh environments (for example, high temperature, oxidizing atmosphere and steam). In such conditions, supported metal catalysts deactivate due to sintering-a process where initially small nanoparticles grow into larger ones with reduced active surface area-but strategies to stabilize them can lead to decreased performance. Here we report stable catalysts prepared through the encapsulation of platinum nanoparticles inside an alumina framework, which was formed by depositing an alumina precursor within a separately prepared porous organic framework impregnated with platinum nanoparticles.

Techno-economic analysis and life cycle assessment of a biorefinery utilizing reductive catalytic fractionation.

Reductive catalytic fractionation (RCF) is a promising approach to fractionate lignocellulose and convert lignin to a narrow product slate. To guide research towards commercialization, cost and sustainability must be considered. Here we report a techno-economic analysis (TEA), life cycle assessment (LCA), and air emission analysis of the RCF process, wherein biomass carbohydrates are converted to ethanol and the RCF oil is the lignin-derived product.

Differences in S/G ratio in natural poplar variants do not predict catalytic depolymerization monomer yields.

The ratio of syringyl (S) and guaiacyl (G) units in lignin has been regarded as a major factor in determining the maximum monomer yield from lignin depolymerization. This limit arises from the notion that G units are prone to C-C bond formation during lignin biosynthesis, resulting in less ether linkages that generate monomers. This study uses reductive catalytic fractionation (RCF) in flow-through reactors as an analytical tool to depolymerize lignin in poplar with naturally varying S/G ratios, and directly challenges the common conception that the S/G ratio predicts monomer yields.

Efficient hydrogen evolution catalysis using ternary pyrite-type cobalt phosphosulphide.

The scalable and sustainable production of hydrogen fuel through water splitting demands efficient and robust Earth-abundant catalysts for the hydrogen evolution reaction (HER). Building on promising metal compounds with high HER catalytic activity, such as pyrite structure cobalt disulphide (CoS2), and substituting non-metal elements to tune the hydrogen adsorption free energy could lead to further improvements in catalytic activity. Here we present a combined theoretical and experimental study to establish ternary pyrite-type cobalt phosphosulphide (CoPS) as a high-performance Earth-abundant catalyst for electrochemical and photoelectrochemical hydrogen production.