Electrochemical reduction of carbon dioxide (CO2) to valuable materials is a promising approach to suppress atmospheric CO2 levels. In order to bring this strategy to a commercial scale, the design of efficient, cost-effective, and robust catalysts is essential. Current advances in CO2 conversion technology use bimetallic components that enhance electrocatalysis via the introduction of binding site diversity. In this work, Sn-Pd bimetallic aerogels supported by carbon nanotubes (Sn-Pd/CNT) demonstrate selective electroreduction of CO2 to formate in ambient conditions. Amino substituents were introduced as an additional CO2 capture site (Sn-Pd/CNT-NH2), further enhancing the electrocatalytic activity and resulting in 91% formate selectively and a current density of -39 mA cm-2 at -0.4 V vs. RHE. The results demonstrate the potential of alloying Sn with other earth-abundant metals to promote the electrochemical conversion of CO2 to value-added materials. We believe this study provides valuable insights into the intricate relationship of bimetallic aerogels and shows the potential of the -NH2 group as a facilitator for CO2 capture and conversion that will inspire new forays into the development of competitive catalytic systems.

Pyrolysis is an effective way to convert biomass into biofuel while obtaining highly porous active carbon materials. In this study, a facile approach, involving hydrothermal and pyrolysis steps, is described for preparing hybrid metal oxide nanoparticle-embedded porous hard carbon matrices (MnO/C) from the biowaste rice husk and organometallic precursors. It was found that the pyrolysis/calcination temperature had a strong influence over the microstructure, especially over the porosity, but also over the carbon content and crystallinity of the nanocomposites; hence, the electrical properties can be controlled. Galvanostatic measurements showed that the nanocomposite obtained at 600 °C exhibited the highest charge/discharge capacity and best stability, delivering an initial discharge capacity of 1104 mA·h·g^-1 at a current density of 200 mA·g^-1, and retaining a value of 830 mA·h·g^-1 after 200 cycles, suggesting excellent cycle stability. A discharge capacity of 581 mA·h·g^-1 was obtained even at a current density as high as 2400 mA·g^-1, demonstrating superb rate capability. This outstanding electrochemical performance, ascribed to high electrochemical activity of the embedded MnO nanoparticles enhanced by electrical conductivity provided through the high surface area of the active porous carbon support, is discussed in relation to the microstructure of the nanocomposite.