The poly(aryl piperidinium)-based anion exchange membrane (PiperION) with high carbonate conductance is employed for CO2 electrolysis to CO in conjunction with a tailored electrolyzer cell structure. This combination results in...
We report formate production via CO2 electroreduction at a Faradaic efficiency (FE) of 93% and a partial current density of 930 mA cm -2 , an activity level of potential industrial interest based on prior techno-economic analyses. We devise a novel catalyst synthesized using InP colloidal quantum dots (CQDs): the capping ligand exchange introduces surface sulfur, and XPS reveals the generation, operando, of an active catalyst exhibiting sulfur-protected oxidized indium and indium metal. Surface indium metal sites adsorb and reduce CO2 molecules, while
Nitrogen-doped graphene-supported single atoms convert CO2 to CO, but fail to provide further hydrogenation to methane – a finding attributable to the weak adsorption of CO intermediates. To regulate the adsorption energy, here we investigate the metal-supported single atoms to enable CO2 hydrogenation. We find a copper-supported iron-single-atom catalyst producing a high-rate methane. Density functional theory calculations and in-situ Raman spectroscopy show that the iron atoms attract surrounding intermediates and carry out hydrogenation to generate methane. The catalyst is realized by assembling iron phthalocyanine on the copper surface, followed by in-situ formation of single iron atoms during electrocatalysis, identified using operando X-ray absorption spectroscopy. The copper-supported iron-single-atom catalyst exhibits a CO2-to-methane Faradaic efficiency of 64% and a partial current density of 128 mA cm−2, while the nitrogen-doped graphene-supported one produces only CO. The activity is 32 times higher than a pristine copper under the same conditions of electrolyte and bias.
Ultraflexible and ultralight rechargeable aqueous Zn-ion batteries (ZIBs) with the merits of environmental benignity and high security arise as promising candidates for flexible electronic systems. Nowadays, the energy density and cyclical stability of ZIBs on metal-based rigid substrates reach a satisfactory level, while the inflexible substrates severely prevent them from widespread commercial adoption in portable electronics. Although flexible substratesengineered devices burgeon, the development of flexible ZIBs with high specific energy still faces great challenges. Herein, a flexible ultrathin and ultralight Zn micromesh (thickness of 8 µm and areal density of 4.9 mg cm −2 ) with regularly aligned microholes is fabricated via combining photolithography with electrochemical machining. The unique microholes-engineered Zn micromesh presents excellent flexibility, enhanced mechanical strength, and better wettability. Moreover, numerical simulations in COMSOL and in situ microscopic observation system certify the induced spatial-selection deposition of Zn micromesh. Accordingly, aqueous ZIBs constructed with polyanilineintercalated vanadium oxide cathode and Zn micromesh anode demonstrate exceptional high-rate capability (67.6% retention with 100 times current density expansion) and cyclical stability (maintaining 87.6% after 1000 cycles at 10.0 A g −1 ). Furthermore, the assembled pouch cell displays superb flexibility and durability under different scenarios, indicating great prospects in high-energy ZIBs and flexible electronics.
Metal borides/borates have been considered promising as oxygen evolution reaction catalysts; however, to date, there is a dearth of evidence of long-term stability at practical current densities. Here we report a phase composition modulation approach to fabricate effective borides/borates-based catalysts. We find that metal borides in-situ formed metal borates are responsible for their high activity. This knowledge prompts us to synthesize NiFe-Boride, and to use it as a templating precursor to form an active NiFe-Borate catalyst. This boride-derived oxide catalyzes oxygen evolution with an overpotential of 167 mV at 10 mA/cm2 in 1 M KOH electrolyte and requires a record-low overpotential of 460 mV to maintain water splitting performance for over 400 h at current density of 1 A/cm2. We couple the catalyst with CO reduction in an alkaline membrane electrode assembly electrolyser, reporting stable C2H4 electrosynthesis at current density 200 mA/cm2 for over 80 h.
Aqueous Zn batteries with ideal energy
density and absolute safety
are deemed the most promising candidates for next-generation energy
storage systems. Nevertheless, stubborn dendrite formation and notorious
parasitic reactions on the Zn metal anode have significantly compromised
the Coulombic efficiency (CE) and cycling stability, severely impeding
the Zn metal batteries from being deployed in the proposed applications.
Herein, instead of random growth of Zn dendrites, a guided preferential
growth of planar Zn layers is accomplished via atomic-scale matching
of the surface lattice between the hexagonal close-packed (hcp) Zn(002)
and face-centered cubic (fcc) Cu(100) crystal planes, as well as underpotential
deposition (UPD)-enabled zincophilicity. The underlying mechanism
of uniform Zn plating/stripping on the Cu(100) surface is demonstrated
by ab initio molecular dynamics simulations and density functional
theory calculations. The results show that each Zn atom layer is driven
to grow along the exposed closest packed plane (002) in hcp Zn metal
with a low lattice mismatch with Cu(100), leading to compact and planar
Zn deposition. In situ optical visualization inspection is adopted
to monitor the dynamic morphology evolution of such planar Zn layers.
With this surface texture, the Zn anode exhibits exceptional reversibility
with an ultrahigh Coulombic efficiency (CE) of 99.9%. The MnO2//Zn@Cu(100) full battery delivers long cycling stability
over 548 cycles and outstanding specific energy and power density
(112.5 Wh kg–1 even at 9897.1 W kg–1). This work is expected to address the issues associated with Zn
metal anodes and promote the development of high-energy rechargeable
Zn metal batteries.
Acidic water electrolysis enables the production of hydrogen
for
use as a chemical and as a fuel. The acidic environment hinders water
electrolysis on non-noble catalysts, a result of the sluggish kinetics
associated with the adsorbate evolution mechanism, reliant as it is
on four concerted proton-electron transfer steps. Enabling a faster
mechanism with non-noble catalysts will help to further advance acidic
water electrolysis. Here, we report evidence that doping Ba cations
into a Co3O4 framework to form Co3–x
Ba
x
O4 promotes
the oxide path mechanism and simultaneously improves activity in acidic
electrolytes. Co3–x
Ba
x
O4 catalysts reported herein exhibit an
overpotential of 278 mV at 10 mA/cm2 in 0.5 M H2SO4 electrolyte and are stable over 110 h of continuous
water oxidation operation. We find that the incorporation of Ba cations
shortens the Co–Co distance and promotes OH adsorption, findings
we link to improved water oxidation in acidic electrolyte.
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