Formic acid (HCOOH) is one of the most promising chemical fuels that can be produced through CO2 electroreduction. However, most of the catalysts for CO2 electroreduction to HCOOH in aqueous solution ...often suffer from low current density and limited production rate. Herein, we provide a bismuth/cerium oxide (Bi/CeOx) catalyst, which exhibits not only high current density (149 mA cm−2), but also unprecedented production rate (2600 μmol h−1 cm−2) with high Faradaic efficiency (FE, 92 %) for HCOOH generation in aqueous media. Furthermore, Bi/CeOx also shows favorable stability over 34 h. We hope this work could offer an attractive and promising strategy to develop efficient catalysts for CO2 electroreduction with superior activity and desirable stability.
The limited current density, production rate as well as selectivity hinder the improvement of HCOOH production from CO2 electroreduction. Here, bismuth/cerium oxide (Bi/CeOx) displays outstanding performances for CO2 electroreduction to HCOOH, which not only shows excellent selectivity, but also achieves a high current density (149 mA cm−2) and especially the maximum HCOOH production rate (2600 μmol h−1 cm−2) ever reported.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Conversion of carbon dioxide (CO2) into valuable chemicals, especially liquid fuels, through electrochemical reduction driven by sustainable energy sources, is a promising way to get rid of ...dependence on fossil fuels, wherein developing of highly efficient catalyst is still of paramount importance. In this study, as a proof‐of‐concept experiment, first a facile while very effective protocol is proposed to synthesize amorphous Cu NPs. Unexpectedly, superior electrochemical performances, including high catalytic activity and selectivity of CO2 reduction to liquid fuels are achieved, that is, a total Faradaic efficiency of liquid fuels can sum up to the maximum value of 59% at −1.4 V, with formic acid (HCOOH) and ethanol (C2H6O) account for 37% and 22%, respectively, as well as a desirable long‐term stability even up to 12 h. More importantly, this work opens a new avenue for improved electroreduction of CO2 based on amorphous metal catalysts.
An amorphous Cu catalyst displays superior catalytic activity toward electroreduction of CO2 with a remarkable selectivity for the reduction to liquid fuels (HCOOH andC2H6O) relative to a crystalline Cu catalyst.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Ammonia synthesis is one of the most kinetically complex and energetically challenging chemical processes in industry and has used the Harber–Bosch catalyst for over a century, which is processed ...under both harsh pressure (150–350 atm) and hightemperature (623–823 K), wherein the energy and capital intensive Harber–Bosch process has a huge energy cost accounting for about 1%–3% of human's energy consumption. Therefore, there has been a rough and vigorous exploration to find an environmentally benign alternative process. As the amorphous material is in a metastable state and has many “dangling bonds”, it is more active than the crystallized one. In this paper, CeOx‐induced amorphization of Au nanoparticles anchored on reduced graphite oxide (a‐Au/CeOx–RGO) has been achieved by a facile coreduction method under ambient atmosphere. As a proof‐of‐concept experiment, a‐Au/CeOx–RGO hybrid catalyst containing the low noble metal (Au loading is 1.31 wt%) achieves a high Faradaic efficiency (10.10%) and ammonia yield (8.3 μg h−1 mg−1cat.) at −0.2 V versus RHE, which is significantly higher than that of the crystalline counterpart (c‐Au/RGO), and even comparable to the yields and efficiencies under harsh temperatures and/or pressures.
CeOx‐induced amorphization of Au nanoparticles anchored on reduced graphite oxide (a‐Au/CeOx–RGO) as a heterogeneous electrocatalyst shows excellent catalytic activity for electrochemical N2 reduction reaction with high Faradic efficiency (10.10%) and ammonia yield (8.3 μg h‐1 mg‐1cat.)
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A novel in situ replication and polymerization strategy is developed for the synthesis of Fe‐N‐doped mesoporous carbon microspheres (Fe‐NMCSs). This material benefits from the synergy between the ...high catalytic activity of Fe‐N‐C and the fast mass transport of the mesoporous microsphere structure. Compared to commercial Pt/C catalysts, the Fe‐NMCSs show a much better electrocatalytic performance in terms of higher catalytic activity, selectivity, and durability for the oxygen reduction reaction.
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As an alternative approach for N2 fixation under milder conditions, electrocatalytic nitrogen reduction reaction (NRR) represents a very attractive strategy for sustainable development and N2 cycle ...to store and utilize energy from renewable sources. However, the research on NRR electrocatalysts still mainly focuses on noble metals, while, high costs and limited resources greatly restrict their large‐scale applications. Herein, as a proof‐of‐concept experiment, taking PdCu amorphous nanocluster anchored on reduced graphene oxide (rGO) as NRR catalysts, the optimum Pd0.2Cu0.8/rGO composite presents a synergistic effect and shows superior electrocatalytic performance toward NRR under ambient conditions (yield: 2.80 µg h−1 mgcat.−1 at −0.2 V vs reversible hydrogen electrode), which is much higher than that of monometallic, especially noble metal, counterparts. The superior catalytic performance of alloy catalysts with low noble metal loading would strongly spur interest toward more researches on NRR catalysts in the future.
PdCu amorphous nanoclusters anchored on graphene are successfully synthesized by a facile coreduction route. The optimum Pd0.2Cu0.8/rGO sample presents enhanced electrocatalytic performance toward electrochemical N2 fixation to NH3 under ambient conditions.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
An artificial while very stable solid electrolyte interphase film is formed on lithium metal using an electrochemical strategy. When this protected Li anode is first used in a Li–O2 battery, the film ...formed on the anode can effectively suppress the parasitic reactions on the Li anode/electrolyte interface and significantly enhance the cycling stability of the Li–O2 battery.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
As the NN bond in N2 is one of the strongest bonds in chemistry, the fixation of N2 to ammonia is a kinetically complex and energetically challenging reaction and, up to now, its synthesis is still ...heavily relying on energy and capital intensive Haber–Bosch process (150–350 atm, 350–550 °C), wherein the input of H2 and energy are largely derived from fossil fuels and thus result in large amount of CO2 emission. In this paper, it is demonstrated that by using Au sub‐nanoclusters (≈0.5 nm ) embedded on TiO2 (Au loading is 1.542 wt%), the electrocatalytic N2 reduction reaction (NRR) is indeed possible at ambient condition. Unexpectedly, NRR with very high and stable production yield (NH3: 21.4 µg h−1 mg−1cat., Faradaic efficiency: 8.11%) and good selectivity is achieved at −0.2 V versus RHE, which is much higher than that of the best results for N2 fixation under ambient conditions, and even comparable to the yield and activation energy under high temperatures and/or pressures. As isolated precious metal active centers dispersed onto oxide supports provide a well‐defined system, the special structure of atomic Au cluster would promote other important reactions besides NRR for water splitting, fuel cells, and other electrochemical devices.
Using Au sub‐nanoclusters anchored on TiO2 substrate as a heterogeneous electrocatalyst, the special Au active sites lead to the effective and stable electrochemical N2 reduction reaction with high NH3 yield (21.4 µg h−1 mg−1cat.) and Faradaic efficiency (8.11%) as well as 100% NH3 selectivity at ambient conditions.
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Several recent studies have shown the presence of genes for the key enzyme associated with archaeal methane/alkane metabolism, methyl-coenzyme M reductase (Mcr), in metagenome-assembled genomes ...(MAGs) divergent to existing archaeal lineages. Here, we study the mcr-containing archaeal MAGs from several hot springs, which reveal further expansion in the diversity of archaeal organisms performing methane/alkane metabolism. Significantly, an MAG basal to organisms from the phylum Thaumarchaeota that contains mcr genes, but not those for ammonia oxidation or aerobic metabolism, is identified. Together, our phylogenetic analyses and ancestral state reconstructions suggest a mostly vertical evolution of mcrABG genes among methanogens and methanotrophs, along with frequent horizontal gene transfer of mcr genes between alkanotrophs. Analysis of all mcr-containing archaeal MAGs/genomes suggests a hydrothermal origin for these microorganisms based on optimal growth temperature predictions. These results also suggest methane/alkane oxidation or methanogenesis at high temperature likely existed in a common archaeal ancestor.
The electrochemical N2 fixation, which is far from practical application in aqueous solution under ambient conditions, is extremely challenging and requires a rational design of electrocatalytic ...centers. We observed that bismuth (Bi) might be a promising candidate for this task because of its weak binding with H adatoms, which increases the selectivity and production rate. Furthermore, we successfully synthesized defect‐rich Bi nanoplates as an efficient noble‐metal‐free N2 reduction electrocatalyst via a low‐temperature plasma bombardment approach. When exclusively using 1H NMR measurements with N2 gas as a quantitative testing method, the defect‐rich Bi(110) nanoplates achieved a 15NH3 production rate of 5.453 μg mgBi−1 h−1 and a Faradaic efficiency of 11.68 % at −0.6 V vs. RHE in aqueous solution at ambient conditions.
Beneficial defects: Defect‐rich bismuth nanoplates achieve a 15NH3 production rate of 5.453 μg mgBi−1 h−1 and a Faradaic efficiency of 11.68 % at −0.6 V vs. RHE in aqueous solutions at ambient conditions because of their poor binding with H adatoms, which increases the selectivity and production rate. Also, 1H NMR measurements with N2 gas ware used as a quantitative test method in aqueous electrolytes.
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