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The scalable and facile preparation of single-atom catalysts remains a critical challenge. Here, we introduce Diluted Atomic Layer Deposition (DALD), a unique approach for synthesizing supported metal catalysts with precisely tunable loadings. Unlike conventional metal deposition by ALD which uses pure metal precursors, DALD employs a diluted precursor mixture, combining organometallic precursors with the corresponding free ligand in controlled ratios. The method enables precise control over metal loadings, allowing the synthesis of structures ranging from nanoparticles to isolated single atoms, as exemplified by Ir, Rh, and Pt on high-surface-area γ-Al2O3. With its inherent simplicity and exceptional efficiency in metal precursor utilization, DALD represents a highly scalable strategy, unlocking opportunities for integrating single-atom catalysts into industrial processes. 

Natural gas at remote locations would greatly benefit from on-site processing using modular technologies such as dehydroaromatization (DHA). This work models an intensified DHA process to increase product yield and methane conversion by coupling the reactor with a chemical looping unit that effectively separates hydrogen through a redox cycle and a temperature swing adsorption process to remove the aromatics and water and recycle unconverted methane. We postulate dynamic models and steady-state surrogate models to analyze and optimize the production of the aromatic product. The optimum methane conversion of 48% and the aromatic yield of 42% occur at a recycle ratio of 0.47 and a reactor temperature of 725 degrees C. 

Microwave-assisted extraction (MAE) of natural antioxidants from food waste (FW) offers an economically appealing waste management strategy. Here, we characterize five single waste streams (apple, coffee, olive, tomato, and potato peel waste) and study the MAE of phenolic acids from select feedstocks and mixtures. This library of materials enables us to unravel the relationship of the FW composition and physical properties with dielectric properties, heating, and extractive yields. For example, the protein, ash, and moisture contents affect dielectric properties the most. Our study unveils the significance of moisture in free and bound states on FW dielectric properties, heating, and target acid yields. The microwaves primarily heat the solvent (dimethylformamide) due to its superior dielectric properties compared to FW (dry and moist, single and mixtures) at ≤ 0.05 solid-to-liquid ratio. High moisture content provides higher phenolic yields at lower temperatures and shorter times due to enhanced heat and mass transfer by the microwaves. We recommend extraction before drying waste streams. Further, our data indicates significant interactions between components of mixed FW that drive 2-3x higher yields than those predicted from a simple additive model from single component results. Our work provides new insights for developing versatile MAE strategies to treat complex mixed FW feedstocks. 

Heat recirculation in Joule-heated reactors. 

Continuous manufacturing of platform chemicals from lignocellulose is highly desirable for a fossil fuel independent future. 

We report that boron -containing zeolite chabazite (B-CHA) catalyzes the oxidative dehydrogenation of ethane (ODHE) with high selectivity (>70 %) and excellent stability in the temperature range of 500-600 degrees C. ODHE rates, in fact, increase over time on stream. Ethane consumption rate has an apparent activation energy of 126 kJ mol(-1), with Langmuirian dependence on the oxygen partial pressure and first-order dependence on the ethane partial pressure. Investigation of the catalyst before and after reaction by one-dimensional B-11 magic angle spinning (1D B-11 MAS) nuclear magnetic resonance (NMR), two-dimensional B-11 multiple quantum MAS (2D B-11 MQMAS) NMR spectroscopy, and Fourier transform infrared (FTIR) spectroscopy identifies the B-OH group in defect trigonal boron (B(OSi)(OH)(2)) as the species initiating the ODHE reaction. This result could open a pathway to develop suitable catalysts for industrial ethylene production with lower greenhouse gas emissions than current non -oxidative dehydrogenation routes.