RESUMEN
Electrochemical conversion of CO2 into fuels using electricity generated from renewable sources helps to create an artificial carbon cycle. However, the low efficiency and poor stability hinder the practical use of most conventional electrocatalysts. In this work, a 2D hierarchical Pd/SnO2 structure, ultrathin Pd nanosheets partially capped by SnO2 nanoparticles, is designed to enable multi-electron transfer for selective electroreduction of CO2 into CH3 OH. Such a structure design not only enhances the adsorption of CO2 on SnO2 , but also weakens the binding strength of CO on Pd due to the as-built Pd-O-Sn interfaces, which is demonstrated to be critical to improve the electrocatalytic selectivity and stability of Pd catalysts. This work provides a new strategy to improve electrochemical performance of metal-based catalysts by creating metal oxide interfaces for selective electroreduction of CO2 .
RESUMEN
By using ethylene glycol and monocarboxylic acid as surface ligands, a series of cyclic Ti-oxo clusters (CTOC) with permanent microporosity are successfully synthesized. With a cyclic {Ti32 O16 } backbone made of eight connected Ti4 tetrahedral cages that are arranged in a zigzag fashion, the clusters have a "donut" shape with an inner diameter of 8.3â Å, outer diameter of 26.9â Å and height of 10.4â Å. While both inner and outer walls of the "donut" clusters are modified by double-deprotonated ethylene glycolates, their upper and lower surfaces are bound by carboxylates and mono-deprotonated ethylene glycolates. The clusters are readily packed into one-dimensional tubes which are further arranged in two different modes into crystalline microporous solids with surface areas over 660â m2 g-1 , depending on the surface carboxylates. The solid with olefin-bearing carboxylates exhibits a superior CO2 adsorption capacity of 40â cm3 g-1 at 273â K under 1â atm. Moreover, the mono-deprotonated ethylene glycolates on the clusters are demonstrated to be highly exchangeable by other alcohols, providing a nice platform for creating microporous solids or films with a wide variety of surface functionalities.