In proton exchange membrane water electrolyzers (PEMWE), the exploration of anode and cathode electrocatalysts with high intrinsic activity and high stability to accommodate extremely acidic conditions is critical for a wide range of industrial applications. In this paper, bifunctional IRCOX nanoalloys with abundant metal vacancies were constructed by combining chemical reduction and electrochemical treatment. Developed IRCO013 exhibits ultra-low overvoltage 238 mV OER and 186 mV her at 10 mA2 01 M HCO4 and reach a special stable of 1000 M HCO2 and 100 h for her at 10 mA cm2. In addition, in order to irco013 is the cathode and anode catalytic layer of PEMWE, the battery voltage is only 168 V, a high current density of 1 A cm2 was achieved, and it exhibited excellent corrosion resistance in an acidic environment, operating stably for 415 h at 1 A cm2. The strong electronic interaction and electrochemical oxidation in the heterostructure of IR-Co atoms generate CO vacancies in situ, which can improve the conductivity and electrochemically active surface area of the catalyst by optimizing the electronic structure of the adjacent IR active sites, accelerate charge transfer and kinetics, and synergistically promote the enhancement of activity and stability. This study provides a new idea for the design of bifunctional catalysts with practical application value.
Preparation process of Ircox nanoalloys containing cobalt vacancies.
a) XRD pattern of IRCOX nanoalloys. (B) SEM images, (C, D) TEM images, (E) EDS element mapping, (F) ACTEM images, (G) IRCO0 after CV processingIntensity distribution plot of the blue rectangular region (Image F) of 13, (H) Size distribution of nanoparticles in Image D.
XPS spectra of IRCOX nanoalloys (A) IR4F and (B) CO2P.
OER performance of IRCOX, homemade IR nanometals, and commercial IR C. (a) by 085 IR corrected polarization curve. (b) Electrochemical impedance spectroscopy (inserted as an equivalent circuit fitted to a Nyquist diagram). (c) Tafel Slope Massif. (d) 1.Current density (J) and mass activity (Jm) at 53 V with RHE. (e) Double-layer capacitance (CDL). Compare (f) electrochemically active surface area, (g) specific activity, and (h) turnover frequency.
(a) by 0LSV curve corrected for 85 IR, (B) IRCO0 after different cycles of CV treatment13 of the mass of metals in the electrolyte (line graph, right) and the percentage of metals in the catalyst (histogram, left).
SHE performance of IRCOX, homemade IR nano-metals, and commercial PT C. (a) by 085 IR corrected polarization curve. (b) Electrochemical impedance spectroscopy (inserted as an equivalent circuit fitted to a Nyquist diagram). (c)tafel。(d)−0.Current density (J) and mass activity (Jm) at 03 V with RHE. (e) Double-layer capacitance (CDL). Compare (f) electrochemically active surface area, (g) specific activity, and (h) turnover frequency.
to IRCO013. Perform a continuous constant current test with (A) OER (inserted at 100 mA cm2) and (B) HER (10 mA cm2).
A, B) TEM image, (C) SEAD image, (D-G) IR, CO and O element mapping, (H) IRCo013Comparison of IR 4F XPS spectra before and after stabilization.
a) With IRC013 / irco0.Schematic diagram of PEMWE of 13. (B) PEMWE polarization curves obtained at 80 using Nafion 115 membrane. (c) Electrochemical impedance spectroscopy (insertion of an equivalent circuit fitting the Nyquist diagram) and (d) constant current test of 1 acm2.
In summary, we have prepared a novel highly active and corrosion-resistant CO-vacancy-rich Ircox bifunctional nanoalloy by chemical reduction and electrochemical oxidation strategies to promote the electrocatalytic overall water splitting in acidic media. The interconnected nanoalloy backbone structure exposes more active sites and provides a transport channel for the release of gaseous products. At the same time, the strong electronic interaction between the IR and CO atoms and the resulting CO vacancies help to improve the constitutive activity and stability of the catalyst by optimizing the electronic structure of adjacent IR active sites. The incorporation of CO increases the conductivity of IR nanometals, increases the electrochemically active surface area, and accelerates charge transfer and Oer&Her kinetics. Therefore, the representative IRCO013 The performance has been significantly improved. In addition, the assembled PEMWE exhibited superior single-cell performance compared to commercial materials (168 v@1 a cm2) and achieved excellent stability under continuous and stable electrolysis for 415 h. This work provides a new strategy for the design and fabrication of bifunctional nanoalloys with high activity and stability.
ultrastable and highly active co-vacancies-enriched irco bifunctional nanoalloys for proton exchange membrane water electrolysis - sciencedirect