Corina Andronescu

Simultaneous electroreduction of CO 2 and H 2 O to syngas can provide a sustainable feed for established processes used to synthesize carbon‐based chemicals. The synthesis of MO x /M‐N‐Cs (M = Ni, Fe) electrocatalysts reported via one‐step pyrolysis that shows increased performance during syngas electrosynthesis at high current densities with adaptable H 2 /CO ratios, e.g., for the Fischer–Tropsch process. When embedded in gas diffusion electrodes (GDEs) with optimized hydrophobicity, the NiO x /Ni‐N‐C catalyst produces syngas (H 2 /CO = 0.67) at −200 mA cm −2 while for the FeO x /Fe‐N‐C syngas production occurs at ≈−150 mA cm −2 . By tuning the electrocatalyst's microenvironment, stable operation for >3 h at −200 mA cm −2 is achieved with the NiO x /Ni‐N‐C GDE. Post‐electrolysis characterization revealed that the restructuring of the catalyst via reduction of NiO x to metallic Ni NPs still enables stable operation of the electrode at −200 mA cm −2 , when embedded in an optimized microenvironment. The ionomer and additives used in the catalyst layer are important for the observed stable operation. Operando Raman measurements confirm the presence of NiO x during CO formation and indicate weak adsorption of CO on the catalyst surface.

The investigation delves into the functionality exhibited by ferroelectric BiFe 0.95 Mn 0.05 O 3 (BFM) nanoparticles (NPs) concerning the hydrogen evolution reaction (HER). The electrocatalytic activity of BFM NPs undergoes a transformative shift as a consequence of mono‐, di‐, and tri‐valent cation substitution. Notably, the strategic engineering of doping at the Bi site within BFM NPs yields a remarkable outcome, namely the conspicuous reduction of the kinetic overpotential prerequisite for HER. This diminished overpotential in doped BFM NPs arises from the confluence of multifarious factors: diminished charge transfer resistance, augmented specific surface area, a discernible distribution of pore sizes ranging from narrow to broad, particles endowed with a shape boasting abundant active facets, and the integration of dopants as novel active sites on the surface. Furthermore, the presence of surface defects, oxygen vacancies, and amplified microstrain within doped BFM NPs contributes to the reduction in overpotential.