A gas diffusion electrode type arrangement was employed to evaluate carbon supported Pb, Bi and Sn nanopowders as electrocatalysts for electrochemical reduction of carbon dioxide in alkaline media (0.5 M NaHCO 3 ). The structural analysis, shape and topographical characterization, and the surface composition analysis of the catalysts were performed by XRD, SEM, TEM and XPS, respectively. The electrochemical techniques used were cyclic voltammetry, linear sweep voltammetry and chronoamperometry. Cyclic voltammetry was used to study the basic redox properties of the surface, while linear sweep was used to measure the response in argon and carbon dioxide saturated solutions. Chronoamperometry was carried out at four potentials to compare the products and their rate of formation for all the catalysts at ambient temperature and pressure. The formate production rate was observed to be highest for lead among the three catalysts evaluated. The value obtained was 0.576 mmol/h at −1.94 V vs RHE with a Faradaic efficiency of ∼ 30%. Further, the activity was found to be stable during the electrolysis and the current density was almost ∼35 mA/cm 2 geo . Based on the experiments conducted in this study, a comparative result of activity towards CO 2 electroreduction to formate was concluded as Pb > Bi > Sn.

Pure phases of Pb, Sn and Pb 70 Bi 30 , their combinations and the eutectics (Pb 25 Sn 75 , Pb 44 Bi 56 and Pb 29 Bi 46 Sn 25) of the Pb-Bi-Sn system were prepared and evaluated for electrochemical reduction of CO 2 at − 2.0 V (vs Hg/HgO). The bulk composition, the phase structure and the surface composition were characterized by inductively ICP-AES, XRD and XPS respectively. The phases obtained from XRD data matches well with the ternary phase diagram of Pb, Bi and Sn. The electrochemical characterization was done by CV and LSV. The formation rate of formate ions was compared for all the alloy catalysts at − 2.0 V (vs Hg/HgO) in CO 2 saturated 0.5 M NaHCO 3. It was observed that addition of both Bi and Sn individually or both concurrently to Pb increases the rate of formate ion production for Pb-Bi, Pb-Sn binary systems and the Pb-Bi-Sn ternary system respectively. Interestingly, it was found out that the eutectic compositions of each alloy system (both binary and ternary) were electrocatalytically superior (Pb-Bi-Sn eutectic (Pb 29 Bi 46 Sn 25) > Pb-Sn eutectic (Pb 25 Sn 75) > Pb-Bi eutectic (Pb 44 Bi 56)). Further, on these high performing eutectics, the hydrogen evolution is greatly suppressed.

UniProt and BFD databases together have 2.5 billion protein sequences. A large majority of these proteins have been electronically annotated. Automated annotation pipelines, vis-à-vis manual curation, have the advantage of scale and speed but are fraught with relatively higher error rates. This is because sequence homology does not necessarily translate to functional homology, molecular function specification is hierarchic and not all functional families have the same amount of experimental data that one can exploit for annotation. Consequently, customization of annotation workflow is inevitable to minimize annotation errors. In this study, we illustrate possible ways of customizing the search of sequence databases for functional homologs using profile HMMs. Choosing an optimal bit score threshold is a critical step in the application of HMMs. We illustrate ways in which an optimal bit score can be arrived at using four Case Studies. These are the single domain nucleotide sugar 6-dehydrogenase and lysozyme-C families, and SH3 and GT-A domains which are typically found as a part of multi-domain proteins. We also discuss the limitations of using profile HMMs for functional annotation and suggests some possible ways to partially overcome such limitations.

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CO2 electroreduction to fuels is one of the most viable solutions for tackling both issues of global warming and energy crises. It is due to the fact that products such as formic acid, methanol, etc. which are obtained by electroreduction of CO2 could be employed as hydrogen carriers or directly as fuels. This phenomenon attracts huge research towards the process and its bottlenecks for making it commercial. The major hurdles regarding catalysis of CO2 electroreduction process are low solubility of CO2 in aqueous solutions and low product yields. In our previous works, we have already demonstrated employment of gas diffusion electrodes for non–noble metal catalysts such as Pb, Bi and Sn. The usage of gas diffusion electrodes enables us to exploit three phase contact of CO2 gas – solid catalysts – liquid electrolyte and shows higher product (formate ion) yield. Additionally, we have also shown through another work that the ternary eutectics of these three non–metal catalysts employed exhibits higher activity for CO2 electroreduction than singular pure metals or any other binary or ternary alloyed compositions of metals. In this work, we want to exploit the conclusions from both the works and subject ternary alloy composition of Pb – Bi – Sn metals in gas diffusion electrode configuration for the process of CO2 electroreduction. Based on the previous two results, author believes that this would enable us to obtain higher product yield and hence better energy efficiency which would be a step forward towards sustainable development.