Electro‐Oxidation of Ni42 Steel: A Highly Active Bifunctional Electrocatalyst

Abstract

Janus type Water-Splitting Catalysts have attracted highest attention as a tool of choice for solar to fuel conversion. AISI Ni 42 steel was upon harsh anodization converted in a bifunctional electrocatalyst. Oxygen evolution reaction-(OER) and hydrogen evolution reaction (HER) are highly efficiently and steadfast catalyzed at pH 7, 13, 14, 14.6 (OER) respectively at pH 0, 1, 13, 14, 14.6 (HER). The current density taken from long-term OER measurements in pH 7 buffer solution upon the electro activated steel at 491 mV overpotential (η) was around 4 times higher (4 mA/cm 2 ) in comparison with recently developed OER electrocatalysts. The very strong voltagecurrent behavior of the catalyst shown in OER polarization experiments at both pH 7 and at pH 13 were even superior to those known for IrO 2 -RuO 2 . No degradation of the catalyst was detected even when conditions close to standard industrial operations were applied to the catalyst. A stable Ni-, Fe-oxide based passivating layer sufficiently protected the bare metal for further oxidation. Quantitative charge to oxygen-(OER) and charge to hydrogen (HER) conversion was confirmed. High resolution XPS spectra showed that most likely γ−NiO(OH) and FeO(OH) are the catalytic active OER and NiO is the catalytic active HER species.

Facile Surface Modification of Ubiquitous Stainless Steel Led to Competent Electrocatalysts for Overall Water Splitting

“…The diffraction peaks of SSF at 44.4°, 51.6°, and 75.4°could be assigned to the (111), (200), and (220) facets of stainless steel, respectively. 39 After sulfurization, all of those Fe-based peaks were wellpreserved in SSFS, along with small peaks at 33.6°, 48.0°, 56.8°, and 64.6°, which could be attributed to Fe 1−x S, NiS, and FeNi 2 S 4 , albeit with low resolution. It should be noted that because only the surface of the stainless steel foil was sulfurized while the inner composition of SSFS remained like that of the bulk SSF ( Figure S3), the resulting XRD pattern of SSFS should inevitably exhibit the XRD peaks of SSF.…”

Free‐Sustaining Three‐Dimensional S235 Steel‐Based Porous Electrocatalyst for Highly Efficient and Durable Oxygen Evolution

“…Raman spectroscopy was performed with aR aman microscope WITec Alpha 300R (30 cm focal length and 600 grooves per mm grating spectrometer) equipped with an EM-CCD (Andor Newton DU970N-BV-353) under the l = 632.8 nm line of aH e-Ne laser with ap ower of 1.5 mW.P owder samples were removed from the contaminated sanding paper by ultrasonication in distilled water. Ap otential range of 0.565 to 0.665 V( vs. RHE), in which no faradaic process occurred, was selected for the capacitance measurements at different scan rates (20,40,60,80,100, and 120 mV s À1 ). The as-prepared 3D S235-P steel plate was directly used as aw orking electrode (WE) on which ap recise surface area of approximately 2cm 2 was defined by insulating tape (Kapton tape).…”

Electro-oxidation of a cobalt based steel in LiOH: a non-noble metal based electro-catalyst suitable for durable water-splitting in an acidic milieu

“…In particular, the stability of non-noble-metal-based electrocatalysts towards oxidative water-splitting of acids needs to be optimized. [20][21][22][23][24][25][26][27] Therefore, the develop-ment of electrocatalysts solely based on nonprecious metals suitable for robust and efficient anodic water-splitting in the acidic regime is of the highest interest, 22 and certainly rep-resents the topic of ongoing research in many groups. Surface modified steels are known to be efficient, stable, cheap and easily accessible electrode materials ideally suited for the electrochemically driven cleavage of water into its elements.…”

“…Surface modified steels are known to be efficient, stable, cheap and easily accessible electrode materials ideally suited for the electrochemically driven cleavage of water into its elements. 20,[28][29][30][31] Until recently, we failed to render steel into an electrocatalyst that can be considered as competitive to Ir-Ru-containing OER electrocatalysts for water-splitting in acids. 20 In this report we evaluate the suitability of a Co based steel as an OER electrocatalyst for the water splitting reaction performed in the acidic regime.…”

“…20,[28][29][30][31] Until recently, we failed to render steel into an electrocatalyst that can be considered as competitive to Ir-Ru-containing OER electrocatalysts for water-splitting in acids. 20 In this report we evaluate the suitability of a Co based steel as an OER electrocatalyst for the water splitting reaction performed in the acidic regime. X20CoCrWMo10-9 steel, basi-cally consisting of Fe, Co, Cr, Mo and W, electro-oxidized in LiOH showed reasonable performance and stability towards long term usage as an OER electrocatalyst in 0.05 M H 2 SO 4 and was found to be highly competitive to recently developed and significantly more expensive OER electrocatalysts working in the acidic environment.…”