Electrochemical reduction of carbon dioxide (CO₂RR) product distribution has been found to be dependent on several key factors, such as catalyst surface morphology, stability, and porosity. Metal-modified carbon-based materials have received a lot of attention in CO₂RR. However, designing a highly active metal carbon catalyst for CO₂RR utilizing low-cost chemical precursors remains a challenge. Here, a series of myristic acid-Phe-Phe peptide (MA-FF) aerogel materials containing graphene oxide (Gox) and Ag nanoparticles have been prepared for electrochemical CO₂RR. The morphologies of the composites were studied by scanning electron microscopy (SEM), and their surface compositions were determined using X-ray photoelectron spectroscopy (XPS). While the peptide aerogel alone showed no catalytic activity for CO₂ electroreduction, the addition of Ag nanoparticles results in a Faradaic efficiency (FE) of 46% for electroreduction of CO₂ to CO at an overpotential of − 0.8 V vs. RHE. Incorporation of Gox in the aerogel increases the FE to 88% and allows CO₂ reduction at a lower overpotential of − 0.7 V vs. RHE. Using highly porous peptide aerogels-Gox in addition to the metal active center provides an enhanced and new method for CO₂ conversion using low environmental impact bio-based aerogels.

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.