Simultaneous Anodic and Cathodic Formate Production in a Paired Electrolyzer by CO2 Reduction and Glycerol Oxidation

Electrochemical CO₂ conversion is a key technology to promote the production of carbon-containing molecules, alongside reducing CO₂ emissions leading to a closed carbon cycle economy. Over the past decade, the interest to develop selective and active electrochemical devices for electrochemical CO₂ reduction emerged. However, most reports employ oxygen evolution reaction as an anodic half-cell reaction causing the system to suffer from sluggish kinetics with no production of value-added chemicals. Therefore, this study reports a conceptualized paired electrolyzer for simultaneous anodic and cathodic formate production at high currents. To achieve this, CO₂ reduction was coupled with glycerol oxidation: a BiOBr-modified gas-diffusion cathode and a Ni_x B on Ni foam anode keep their selectivity for formate in the paired electrolyzer compared to the half-cell measurements. The paired reactor here reaches a combined Faradaic efficiency for formate of 141 % (45 % anode and 96 % cathode) at a current density of 200 mA cm^-2 .

Advanced (photo)electrocatalytic approaches to substitute the use of fossil fuels in chemical production

Electrification of the chemical industry for carbon-neutral production requires innovative (photo)electrocatalysis. This study highlights the contribution and discusses recent research projects in this area, which are relevant case examples to explore new directions but characterised by a little background research effort. It is organised into two main sections, where selected examples of innovative directions for electrocatalysis and photoelectrocatalysis are presented. The areas discussed include (i) new approaches to green energy or H2 vectors, (ii) the production of fertilisers directly from the air, (iii) the decoupling of the anodic and cathodic reactions in electrocatalytic or photoelectrocatalytic devices, (iv) the possibilities given by tandem/paired reactions in electrocatalytic devices, including the possibility to form the same product on both cathodic and anodic sides to "double" the efficiency, and (v) exploiting electrocatalytic cells to produce green H2 from biomass. The examples offer hits to expand current areas in electrocatalysis to accelerate the transformation to fossil-free chemical production.

Iridium-incorporated Co3O4 with lattice expansion for energy-efficient green hydrogen production coupled with glycerol valorization

The iridium-incorporated Co₃O₄ (Ir-Co₃O₄) catalyst is obtained from binary CoIr-based metal-organic framework precursors via controlled calcination treatment. Structural characterization reveals that in situ incorporation of Ir cations can cause lattice expansion of Co₃O₄ and regulate its electronic structure, thus in turn favoring electrocatalytic performance improvement. With a lattice expansion-induced strain effect, the Ir-Co₃O₄ catalyst shows superior performance for both electrocatalytic glycerol-to-formate conversion and the hydrogen evolution reaction.

On the Mediated Electron Transfer of Immobilized Galactose Oxidase for Biotechnological Applications

The use of enzymes as catalysts in chemical synthesis offers advantages in terms of clean and highly selective transformations. Galactose oxidase (GalOx) is a remarkable enzyme with several applications in industrial conversions as it catalyzes the oxidation of primary alcohols. We have investigated the wiring of GalOx with a redox polymer; this enables mediated electron transfer with the electrode surface for its potential application in biotechnological conversions. As a result of electrochemical regeneration of the catalytic center, the formation of harmful H₂O₂ is minimized during enzymatic catalysis. The introduced bioelectrode was applied to the conversion of bio‐renewable platform materials, with glycerol as model substrate. The biocatalytic transformations of glycerol and 5‐hydroxymethylfurfural (HMF) were investigated in a circular flow‐through setup to assess the possibility of substrate over‐oxidation, which is observed for glycerol oxidation but not during HMF conversion.