Porous monolithic catalysts with high specific surface areas, which can not only facilitate heat/mass transfer, but also help to expose active sites, are highly desired in strongly exothermic or endothermic gas–solid phase reactions. In this work, hierarchical spinel monolithic catalysts with a porous woodpile architecture were fabricated via extrusion-based three-dimensional (3D) printing (direct ink writing, DIW in brief) of aluminate-intercalated layered double hydroxide (AI-LDH) followed by low temperature calcination. The intercalation of aluminate in LDH is found crucial to tailor the M2+/Al3+ ratio, integrate LDH nanosheets into monolithic catalyst, and enable the conversion of LDH to spinel at the temperature as low as 500 °C with high specific surface areas (> 350 m2/g). The rapid mass/heat transfer resulted from the versatile 3D network at macroscale and the highly dispersed and fully exposed active sites benefited from the porous structure at microscale endow the 3D-printed Pd loaded spinel MgAl-mixed metal oxide (3D-AI-Pd/MMO) catalyst with excellent catalytic performance in semi-hydrogenation of acetylene, achieving 100% conversion at 60 °C with more than 84% ethylene selectivity.
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Amorphous alloys, also known as metallic glasses, are solid metallic materials having long-range disordered atomic structures. Compared to crystalline alloys, amorphous alloys not only have metallic characters, but also possess several distinct properties associated to the amorphous structure, such as isotropy, composition flexibility, unsaturated surface, etc. As a result, amorphous alloys offer a class of highly promising materials for catalyzing electrochemical reactions. In this minireview, the preparation, characterization and electrocatalytic performances of a variety of metallic amorphous alloy materials are summarized. The influences of the amorphous alloy structure on different electrochemical reactions are discussed. Finally, a summary on the advantages and challenges of amorphous alloys in electrocatalysis is provided, along with some perspectives about the future research directions.
Hydrogen production from steam or autothermal alcohol reforming has been widely studied, but these methods require high temperatures and emit CO2. Here, we present a new strategy for the simultaneous room-temperature production of hydrogen and other chemicals without the emission of CO2, via the photoelectrochemical reforming of biomass-derived alcohols. The measured hydrogen quantum efficiencies reach around 80% across the entire visible solar spectrum from 450 to 850 nm, achieving an ultrahigh hydrogen production rate of 7.91 μmol/(min·cm2) under AM 1.5G illumination.