RESUMEN
The electrochemical CO2 reduction reaction (CO2 RR) to syngas represents a promising solution to mitigate CO2 emissions and manufacture value-added chemicals. Palladium (Pd) has been identified as a potential candidate for syngas production via CO2 RR due to its transformation to Pd hydride under CO2 RR conditions, however, the pre-hydridized effect on the catalytic properties of Pd-based electrocatalysts has not been investigated. Herein, pre-hydridized Pd nanocubes (PdH0.40 ) supported on carbon black (PdH0.40 NCs/C) are directly prepared from a chemical reduction method. Compared with Pd nanocubes (Pd NCs/C), PdH0.40 NCs/C presented an enhanced CO2 RR performance due to its less cathodic phase transformation revealed by the in situ X-ray absorption spectroscopy. Density functional theory calculations revealed different binding energies of key reaction intermediates on PdH0.40 NCs/C and Pd NCs/C. Study of the size effect further suggests that NCs of smaller sizes show higher activity due to their more abundant active sites (edge and corner sites) for CO2 RR. The pre-hydridization and reduced NC size together lead to significantly improved activity and selectivity of CO2 RR.
RESUMEN
The electrochemical reduction of carbon dioxide (CO2) on copper electrode derived from cupric oxide (CuO), named oxide derived copper (ODCu), was studied thoroughly in the potential range of -1.0 V to -1.5 V versus RHE. The CuO nanoparticles were prepared by the hydrothermal method. The ODCu electrode was used for carbon dioxide reduction and the results revealed that this electrode is highly selective for C2+ products with enhanced current density at significantly less overpotential. This catalyst shifts the selectivity towards C2+ products with the highest Faradaic efficiency up to 58% at -0.95 V. In addition, C2 product formation at the lowest onset potential of -0.1 V is achieved with the proposed catalyst. X-ray diffraction and scanning electron microscopy revealed the reduction of CuO to Cu (111) nanoparticles during the CO2 RR. The intrinsic property of the synthesized catalyst and its surface reduction are suggested to induce sites or edges for facilitating the dimerization and coupling of intermediates to ethanol and ethylene.
RESUMEN
The enzyme, Formate Dehydrogenase, is biological catalyst responsible for the hydrogenation of carbon dioxide to formic acid. The present research has discovered CO2 reduction activities and their application using certain metal containing (Mo- or W-)/ NAD + -linked Formate Dehydrogenases. However, the enzyme must be immobilized for easy separation, increased stability and reusability. The shortcomings associated with conventional immobilization method include leaching, mass transfer limitation and low activity. We here present a perspective, wherein, we assess the efficacy of soft-oxometalates and macrocycles as a promising alternative to Formate Dehydrogenase immobilization. The mechanistic pathway and stability of Formate Dehydrogenase from different sources are discussed and compared with their tailored 'chemical counterparts' soft-oxometalates and macrocycles based systems such as {Mo132}, {Mo154}, {MoV9}, Co and Mn based Corroles. The structure, properties and mechanism of CO2 reduction by different Soft-oxometalates and metal based macrocycles were found to be synonymous with that of metal based Formate Dehydrogenase. We comprehensively summarize different reported approaches to valorize CO2 to C1 and C2 products such as photochemical, electrochemical and systems chemistry to showcase our efforts in the ongoing pursuit of CO2 valorization, inspired by the workings of such enzymes, alongside the efforts of several other leading groups. The revelatory insights in the perspective could be used not only for developing bio-inspired CO2 Reduction Reaction but also constructing artificial cell automata for artificial life like system.