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. These catalysts do not sinter at 800 °C in the presence of oxygen and steam, conditions in which conventional catalysts sinter to a large extent, while showing similar reaction rates. Extending this approach to Pd-Pt bimetallic catalysts led to the small particle size being maintained at temperatures as high as 1,100 °C in air and 10% steam. This strategy can be broadly applied to other metal and metal oxides for applications where sintering is a major cause of material deactivation

Molecular Additives Improve Selectivity of CO2 Photoelectrochemical Reduction over Gold Nanoparticles on Gallium Nitride

Photoelectrochemical CO2 reduction (CO2R) is an appealing solution to convert carbon dioxide into higher-value products. However, CO2R in aqueous electrolytes suffers from poor selectivity due to the competitive hydrogen evolution reaction dominant on semiconductor surfaces in aqueous electrolytes. We demonstrate that functionalizing gold/p-type gallium nitride devices with a film derived from diphenyliodonium triflate suppresses hydrogen generation from 90% to 18%. As a result, we observe an increase in the Faradaic efficiency and partial current density for carbon monoxide by 50% and 3x, respectively. Furthermore, we demonstrate through optical absorption measurements that the molecular film employed herein, regardless of thickness, does not affect the photocathode’s light absorption and, therefore, photocurrent. Together, this study provides a rigorous platform to elucidate catalytic structure-property relationships to enable engineering of active, stable, and selective materials for photoelectrochemical CO2 reduction

Comparison between Landfill Gas and Waste Incineration for Power Generation in Astana

ABSTRACT The city of Astana, capital of Kazakhstan with population of 804,474 people and a rapid growth in the last 15 years, generates approximately 1.39 kg capita Astana as most urban areas in developing nations faces great challenges in the management of its MSW, whereas at the same time its rapid growth demands more and more energy in its path to development. Thus, the practical possibility to use MSW to generate electricity should be evaluated. This paper presents a prefeasibility study aiming to identify the better waste-to-energy technology to be implemented in Astana. The performance of landfill gas (LFG) and waste incineration (WI) technologies were compared, via technical-economic simulation of the corresponding Net GHG Reduction (tCO 2 y

Templated Encapsulation of Pt-based Catalysts Promotes High-Temperature Stability to 1,100 °C

Stable catalysts are essential to address energy and environmental challenges, especially in harsh environment applications (high temperature, oxidizing atmosphere, 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. Strategies to stabilize them lead to decreased performance. Here, we report stable catalysts prepared through the encapsulation of platinum particles inside an alumina framework. These catalysts do not sinter at 800 °C in the presence of oxygen and steam, conditions in which conventional catalysts sinter to large extents, while showing similar reaction rates. Extending this approach to Pd/Pt bimetallic catalysts leads to maintained small particle size at temperatures as high as 1,100 °C in air and steam. This strategy can be broadly applied to other metal and metal oxides for applications where sintering is a major cause of materials deactivation