Nickel Surface Area Research Articles

Hierarchical 3D porous trimetallic palladium-iron and cobalt on nickel foam as electrocatalyst for large current density oxygen evolution reaction in alkaline seawater

Electrolysis in seawater is a low-cost but difficult method of producing hydrogen. Herein, self-assembled hierarchical three-dimensional (3D) porous trimetallic palladium-iron and cobalt oxide anchored on a cheap and high surface area nickel foam (NF) (PdFeCo3−xO4/NF) were synthesized using a simple and low-cost impregnation-hydrothermal and thermal reduction strategy. The as-fabricated PdFeCo3−xO4/NF electrode showed both superhydrophilic and superaerophobic properties, which favored the fat removal of oxygen bubbles from the electrode surface owing to the close interaction between the electrode and electrolyte. Furthermore, the significant synergistic effect of trimetallics and the NF-matrix resulted in substantially enhanced oxygen evolution reaction (OER) intrinsic activity. The self-assembled PdFeCo3−xO4/NF catalyst exhibited critical low overpotentials of 300 and 340 mV to achieve an extremely large current density of 100 mA cm−2 in 1 M KOH solution and 1 M KOH seawater. Cell voltages as low as 1.44 and 1.51 V were required to drive 10 mA cm−2 in alkaline solution and seawater electrolytes for the full cell overall water splitting performance. This work suggests a promising strategy for developing next-generation electrocatalysts appropriate for natural seawater with cost-effective.

Dry reforming of methane over sub-stoichiometric NiAl2O4-mediated Ni/Al2O3 catalysts

A series of Ni/Al2O3 catalysts were prepared from substoichiometric NiAl2O4 precursors (Ni/Al molar ratio between 0.5 and 0.05) were examined for the dry reforming of methane. The calcined spinel precursors and the corresponding reduced catalysts were characterised by N2 physisorption, X-ray fluorescence, X-ray diffraction, Raman spectroscopy, electronic microscopy coupled to elemental mapping, X-ray photoelectron spectroscopy and temperature-programmed techniques. Compared with the stoichiometric counterpart, nickel species present in Ni-deficient precursors were mostly in the form of a spinelic phase. After high-temperature reduction, narrow particle size distributions centred at 10 nm were obtained. The largest available nickel surface area (18 m2g−1) was exhibited by the catalyst derived from the precursor with a Ni/Al of 0.15. The NiAl2O4-mediated catalysts, especially those with Ni/Al molar ratio in the 0.15–0.25 range, exhibited a notable performance at 90,000 h−1 and 650 °C. The optimal catalyst (14%wt.%Ni), with 93%CH4 and 80%CO2 conversions, was also able to operate for 200 h despite the significant formation of carbonaceous nanotubes (around 1gCgCAT-1) and were examined.

Origin-of-life Molecules in the Atmosphere after Big Impacts on the Early Earth

The origin of life on Earth would benefit from a prebiotic atmosphere that produced nitriles, like HCN, which enable ribonucleotide synthesis. However, geochemical evidence suggests that Hadean air was relatively oxidizing with negligible photochemical production of prebiotic molecules. These paradoxes are resolved by iron-rich asteroid impacts that transiently reduced the entire atmosphere, allowing nitriles to form in subsequent photochemistry. Here we investigate impact-generated reducing atmospheres using new time-dependent, coupled atmospheric chemistry and climate models that account for gas-phase reactions and surface catalysis. The resulting H2-, CH4-, and NH3-rich atmospheres persist for millions of years, until the hydrogen escapes to space. The HCN and HCCCN production and rainout to the surface can reach 109 molecules cm−2 s−1 in hazy atmospheres with a mole ratio of CH4/CO2 > 0.1. Smaller CH4/CO2 ratios produce HCN rainout rates of <105 molecules cm−2 s−1 and negligible HCCCN. The minimum impactor mass that creates atmospheric CH4/CO2 > 0.1 is 4 × 1020–5 × 1021 kg (570–1330 km diameter), depending on how efficiently iron reacts with a steam atmosphere, the extent of atmospheric equilibration with an impact-induced melt pond, and the surface area of nickel that catalyzes CH4 production. Alternatively, if steam permeates and deeply oxidizes the crust, impactors of ∼1020 kg could be effective. Atmospheres with copious nitriles have >360 K surface temperatures, perhaps posing a challenge for RNA longevity, although cloud albedo can produce cooler climates. Regardless, postimpact cyanide can be stockpiled and used in prebiotic schemes after hydrogen has escaped to space.

Effect of Re Addition on the Water–Gas Shift Activity of Ni Catalyst Supported by Mixed Oxide Materials for H2 Production

Water–gas shift (WGS) reaction was performed over 5% Ni/CeO2, 5% Ni/Ce-5% Sm-O, 5% Ni/Ce-5% Gd-O, 1% Re 4% Ni/Ce-5% Sm-O and 1% Re 4% Ni/Ce-5% Gd-O catalysts to reduce CO concentration and produce extra hydrogen. CeO2 and M-doped ceria (M = Sm and Gd) were prepared using a combustion method, and then nickel and rhenium were added onto the mixed oxide supports using an impregnation method. The influence of rhenium, samarium and gadolinium on the structural and redox properties of materials that have an effect on their water–gas shift activities was investigated. It was found that the addition of samarium and gadolinium into Ni/CeO2 enhances the surface area, reduces the crystallite size of CeO2, increases oxygen vacancy concentration and improves Ni dispersion on the CeO2 surface. Moreover, the addition of rhenium leads to an increase in the WGS activity of Ni/CeMO (M = Sm and Gd) catalysts. The results indicate that 1% Re 4% Ni/Ce-5% Sm-O presents the greatest WGS activity, with the maximum of 97% carbon monoxide conversion at 350 °C. An increase in the dispersion and surface area of metallic nickel in this catalyst results in the facilitation of the reactant CO adsorption. The result of X-ray absorption near-edge structure (XANES) analysis suggests that Sm and Re in 1% Re 4% Ni/Ce-5% Sm-O catalyst donate some electrons to CeO2, resulting in a decrease in the oxidation state of cerium. The occurrence of more Ce3+ at the CeO2 surface leads to higher oxygen vacancy, which alerts the redox process at the surface, thereby increasing the efficiency of the WGS reaction.

A low-temperature ammonia electrolyser for wastewater treatment and hydrogen production

Ammonia is a pollutant present in wastewater and is also a valuable, carbon-free hydrogen carrier. Stripping, recovery, and anodic oxidation of ammonia to produce hydrogen via electrolysis is gaining momentum as a technology, yet the development of an inexpensive, stable catalytic material is imperative to reduce cost. Here, we report on a new nickel-copper (NiCu) catalyst electrodeposited onto a high surface area nickel felt (NF) as an anode for ammonia electrolysis. Cyclic voltammetry demonstrated that the catalyst/substrate combination reached the highest current density (200 mA cm−2 at 20 °C) achieved for a non-noble metal catalyst. A NiCu/NF electrode was tested in an anion exchange membrane electrolyser for 50 h; it showed good stability and high Faradaic efficiency for ammonia oxidation (88%) and hydrogen production (99%). We demonstrate that this novel electrode catalyst/substrate material combination can oxidise ammonia in a scaled system, and hydrogen can be produced as a valuable by-product at industrial-level current densities and cell voltages lower than that for water electrolysis.

Surfactant-assisted hydrothermal synthesis of large surface area nickel nanoparticles for electrochemical applications

A large surface area is an imperative parameter for electrocatalytic materials applied in electrochemical devices. In the present work, Ni nanoparticles were synthesized by hydrothermal method using three surfactants: sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and polyvinyl pyrrolidone (PVP) and two base media, i.e., sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH). We investigated the effects of different surfactants and base mediums on Ni nanoparticles' crystallite size, particle size, and surface area. Experimental results revealed that Ni nanoparticles with smaller particle sizes (50–90 nm) and large surface area (28.4–64 m2/g) were obtained when NaOH was used as the base medium with all surfactants. Further, a high specific capacitance of 417 F/g, minimum charge transfer resistance of 490 Ω, and 91 % capacitance retention demonstrated that Ni nanoparticles obtained using PVP in NaOH could be applied as potential working electrode material in enhancing the performance of supercapacitor devices.

Photovoltaic–Electrolyzer System Operated at &gt;50 mA cm−2 by Combining Large‐Area Shingled Silicon Photovoltaic Module with High Surface Area Nickel Electrodes for Low‐Cost Green H2 Generation

Green hydrogen plays an important role in the energy transition as a renewable energy vector for long‐duration energy storage and as feedstock chemical for the industry. To reduce the price below 1.5 € kg−1 H2, competitive to production from fossil fuels, silicon photovoltaic (PV)‐powered efficient anion‐exchange membrane (AEM) water electrolysis is a promising combination. Practical implementation of such a photovoltaic–electrolyzer (PV–EC) technology requires standard area‐sized solar cells and electrolyzers operating at large current densities. Nonetheless, state‐of‐the‐art research often employs &lt;10 cm2 PV devices and electrolyzers operated at &lt;10 mA cm−2. Herein, a commercially relevant PV–EC system combining shingled standard silicon technology with efficient low‐cost AEM electrolysis using high‐surface‐area (26 m2 cm−3) nickel nanomesh electrodes is presented. The produced H2, operating current, and voltage are in situ monitored over &gt;20 h yielding a stable solar‐to‐hydrogen efficiency (ηSTH) of 10% at electrolyzer current densities ≈60 mA cm−2 and dynamic load testing up to 300 mA cm−2 results in stable performance. Based on the measured PV–EC system data, best practices to accurately determine the ηSTH for PV‐powered water‐splitting devices and the validation of this benchmark against important component parameters for practical implementation of this technology are discussed.

UiO-66-derived Ce/Ni-ZrO2 nano-catalysts with a large nickel surface area for the highly efficient CO2 methanation under high GHSVs

In this work, a new preparation method is developed for the preparation of Ce/Ni-ZrO2 nano-catalyst (Ce/Ni-ZrO2-N). Although similar catalytic systems have been studied by many others, there is still a need for improvement in terms of nickel surface area, catalytic efficiency, and insights of the mechanism. The Ce/Ni-ZrO2-N developed in this study exhibits a large nickel surface area (50.6 m2∙g−1) and a small nickel particle size (∼5.1 nm). During the preparation of such a catalyst, UiO-66 is used not only as a precursor for the preparation of ZrO2 with a large surface area but also as a dispersant for confining nickel nanoparticles. The catalyst demonstrates an excellent catalytic performance at high GHSVs. With a 16-fold increase in GHSVs, the CO2 conversion of Ce/Ni-ZrO2-N only decreases by 32.1 %, whereas that of the control group drops by 50.3 %. This is attributed to the high nickel surface area and relatively low activation energy. Moreover, the characterization and Density Functional Theory (DFT) studies reveal that electron transfer from Ce to Ni enhances the activation of CO2 on the Ni sites, which subsequently contributes to a better catalytic performance. In addition, the catalyst shows excellent anti-coking ability during the 40 h's testing, which, according to DFT calculations, is attributed to the high energy barrier for coke formation on the active sites.

Nickel-Alumina Catalysts for the Transformation of Vegetable Oils into Green Diesel: The Role of Preparation Method, Activation Temperature, and Reaction Conditions.

Two nickel alumina catalysts containing 60 wt. % Ni were synthesized by wet impregnation and co-precipitation in order to study the effect of preparation methods on the catalytic efficiency concerning the transformation of sunflower oil into green diesel. The effect of activation temperature on the catalytic efficiency of the most active catalyst was also studied. The catalysts were characterized using various techniques and which were evaluated in the aforementioned reaction using a semi-batch reactor. The catalyst prepared by co-precipitation exhibited a higher specific surface area and smaller mean crystal size of the nickel nanoparticle (higher nickel metallic surface). These justify its higher efficiency with respect to the corresponding catalyst synthesized by wet impregnation. The increase in the activation temperature from 400 to 600 °C increased the size of the nickel nanoparticles through sintering, thus destroying the small pores. These led to a decrease in the nickel surface and specific surface area and, thus, to a decrease in the catalytic efficiency. The optimization of the reaction conditions over the most active catalyst (prepared by co-precipitation and activated at 400 °C) leads to the complete transformation not only of the sunflower oil (edible oil) but also of waste cooking oil (non-edible oil) into green diesel. The liquid produced after the hydrotreatment for these two feedstocks for 7 h, at H2 pressure 40 bar and temperature 350 °C using 100 mL of oil and 1 g of catalyst was composed of 97 and 96 wt. % of green diesel, respectively.

Enabling technologies for the continuous electrically driven conversion of CO2 and water to multi-carbon products at high current densities

We report a soft-templating method for the synthesis of high surface area nickel phosphide catalyst (Ni2P). Ni2P exhibits a 40–50% CO2 reduction products selectivity over H2 formation at current densities ranging from 50–300 mA cm−2 in a flow cell.

Insight into the effect of CeO2 morphology on catalytic performance for steam reforming of glycerol

Shape-specific CeO2 nanocrystals (spheres, rods, cubes and nanoparticles) with well-defined crystal facets were successfully synthesized and used as the support to synthesize series Ni/CeO2. Ni/CeO2 was employed as the model catalysts to study the structure dependent behavior and reaction mechanism for hydrogen production from glycerol steam reforming (GSR). The metal-support interaction was finely tuned by altering the morphology of CeO2 support, which in turn affected the exposed specific surface area of nickel and oxygen vacancy concentration. The relationship between exposed surface area of active nickel as well as surface oxygen vacancies and catalytic performance was studied. Ni/CeO2-S with the mainly exposed (111) type planes obtained the strongest metal-support interaction. Electron effects due to the strong metal-support between nickel and cerium dioxide facilitated the formation of readily reducible nickel species (Niδ+). High nickel reduction and nickel dispersion contributed to the maximum active nickel exposure surface area, thus Ni/CeO2-S showed exceptional glycerol conversion. Meanwhile, the strong Ni-CeO2 interaction resulting in abundant oxygen vacancies that facilitated the dissociation of water to produce hydrogen, thus possessing a high H2 yield. Conversely, Ni/CeO2-NR and Ni/CeO2-NC have lower exposure areas and oxygen vacancy concentrations due to the different exposed crystal planes, and therefore have relatively poor catalytic activity. Moreover, the strong oxygen storage-release ability (CO-OSC-OSCC) promoted the oxidation of carbon deposition on Ni/CeO2-S. Additionally, carbon deposition was mainly the filamentous carbon growing towards the periphery, hence, Ni/CeO2-S obtained up to 25-h catalytic stability. The study of the regulatory role of Ni-CeO2 interaction on catalytic behavior can offer worthwhile direction for designing high-efficiency GSR catalysts.

Nanoarchitectonics of Ni/CeO2 Catalysts: The Effect of Pretreatment on the Low-Temperature Steam Reforming of Glycerol.

CeO2 nanosphere-supported nickel catalysts were prepared by the wetness impregnation method and employed for hydrogen production from glycerol steam reforming. The dried catalyst precursors were either reduced by H2 after thermal calcination or reduced by H2 directly without calcination. The catalysts that were reduced by H2 without calcination achieved a 95% glycerol conversion at a reaction temperature of only 475 °C, and the catalytic stability was up to 35 h. However, the reaction temperature required of catalysts reduced by H2 with calcination was 500 °C, and the catalysts was rapidly inactivated after 25 h of reaction. A series of physicochemical characterization revealed that direct H2 reduction without calcination enhanced the concentration of oxygen vacancies. Thus, the nickel dispersion was improved, the nickel nanoparticle size was reduced, and the reduction of nickel was increased. Moreover, the high concentration of oxygen vacancy not only contributed to the increase of H2 yield, but also effectively reduced the amount of carbon deposition. The increased active nickel surface area and oxygen vacancies synergistically resulted in the superior catalytic performance for the catalyst that was directly reduced by H2 without calcination. The simple, direct hydrogen reduction method remarkably boosts catalytic performance. This strategy can be extended to other supports with redox properties and applied to heterogeneous catalytic reactions involving resistance to sintering and carbon deposition.

Cyclohexylammonium Hexaisothiocyanatonickelate(II) Dihydrate as a Single-Source Precursor for High Surface Area Nickel Oxide and Sulfide Nanocrystals

Cyclohexylammonium hexaisothiocyanatonickelate(II) dihydrate, (C6H11NH3)4[Ni(NCS)6]·2H2O, was synthesized, for the first time, by a four-step method in a yield of 95%. The compound was fully characterized by elemental microanalysis, Fourier transform infrared (FTIR), ultraviolet-visible-near infrared (UV-Vis-NIR), and nuclear magnetic resonance (NMR) spectroscopy and thermogravimetry. A single crystal X-ray diffraction (SXRD) gave the monoclinic space group P21/c with a = 15.8179 (5) Å, b = 10.6222 (3) Å, c = 13.8751 (4) Å, β = 109.362 (1)°, V = 2199.45 (11) Å3, Z = 2 (T = 293 K) for this novel hybrid organic–inorganic compound. The title compound was employed as a single-source precursor for the synthesis of mesoporous, high surface area nickel oxide (53 Å; 452 m2/g) and nickel sulfide (46 Å; 220 m2/g) via pyrolysis under air at 550 °C or helium atmosphere at 500 °C, respectively. X-ray powder diffraction (XRPD) demonstrated the nanocrystalline nature of both NiO and NiS with an average crystallite size of 16 and 54 nm, respectively. Scanning electron microscope (SEM) indicated the formation of agglomerated, quasi-spherical particles of nickel oxide and agglomerated flake-like structures of nickel sulfide. The high surface area, porosity, and nanocrystallinity of both NiO and NiS, obtained via this approach, are promising for a wide spectrum of applications.

Heterogeneous Enantioselective Catalysis with Chiral Encoded Mesoporous Pt-Ir Films Supported on Ni Foam.

The development of heterogeneous catalysts for asymmetric synthesis is one of the most challenging topics in chemistry, as it allows obtaining enantiomerically pure compounds. Recently, metal layers incorporating molecular chiral cavities, obtained by electroreduction of a metal source in the simultaneous presence of a non-ionic surfactant and asymmetric molecules, have been proposed for a wide range of applications, including enantioselective electroanalysis and electrosynthesis, as well as chiral separation. In contrast to this previous work, solely based on electrochemical phenomena, herein we designed and employed nanostructured chiral encoded Pt-Ir alloys, supported on high surface area nickel foams, as heterogeneous catalysts for the asymmetric hydrogenation of aromatic ketones. Fine-tuning the experimental conditions allows achieving very high enantioselectivity (>80%), combined with improved catalyst stability.

Synergistic effects of α-Fe2O3 nanoparticles and Fe-doping on gas-sensing performance of NiO nanowires and interface mechanism

High surface area nickel oxide nanowires (NiO NWs), Fe-doped NiO NWs and α-Fe2O3/Fe-doped NiO NWs were synthesized with nanocasting pathway, and then the morphology, microstructure and components of all samples were characterized with XRD, TEM, EDS, UV–vis spectra and nitrogen adsorption–desorption isotherms. Owing to the uniform mesoporous template, all samples with the same diameter exhibit the similar mesoporous-structures. The loaded α-Fe2O3 nanoparticles should exist in mesoporous channels between Fe-doped NiO NWs to form heterogeneous contact at the interface of n-type α-Fe2O3 nanoparticles and p-type NiO NWs. The gas-sensing results indicate that Fe-dopant and α-Fe2O3-loading both improve the gas-sensing performance of NiO NWs sensors. α-Fe2O3/Fe-doped NiO NWs sensors presented the highest response to 100 ppm ethanol gas (55.264) compared with Fe-doped NiO NWs (24.617) and NiO NWs sensors (3.189). The donor Fe-dopant increases the ground state resistance and the absorbed oxygen content in air. α-Fe2O3 nanoparticles in electron depletion region result in the increasing resistance in ethanol gas and decreasing resistance in air. In this way, α-Fe2O3/Fe-doped NiO NWs sensor presents the excellent gas-sensing performance due to the formation of heterogeneous contact at the interface.

W promoted Ni-Al2O3 co-precipitated catalysts for green diesel production

The promoting action of W in the Ni-Al2O3 co-precipitated catalysts with high nickel loading (31–46 wt% Ni) has been investigated in the selective deoxygenation of sunflower oil and waste cooking oil towards green diesel production. A WNi-Al2O3 catalyst containing 8 wt% W and 35 wt% Ni (NiNi+W=0.9 atomic ratio) proven the most efficient. The detailed characterization of the catalysts allowed an insight concerning the tungsten promoting action. It was attributed to the increase in the catalyst specific surface area and metallic nickel surface area, the acidity regulation, the decrease of the amount of catalytically inactive nickel aluminate formed and to the participation of W5+-oxo species via their defect oxygen sites in the selective deoxygenation network. The optimum reduction – activation temperature was found at 500 °C, where a good compromise between the increase of metallic Ni relative amount, the decrease of the specific surface area and the increase of Ni mean crystal size is achieved.

A numerical study on the active reaction thickness of nickel catalyst layers used in a low-pressure steam methane reforming process

With the advancement of fuel cell technologies and growing interest in the hydrogen economy, the small-scale, distributed production of hydrogen has recently been receiving considerable research attention. The steam methane reforming (SMR) process, an established industrial process for large-scale hydrogen production, can also be successfully deployed for small-scale, low-pressure hydrogen production systems, including compact reformers, microchannel reformers, plate reformers, and monolithic reformers. In this study, the active reaction thickness of nickel catalyst layers was numerically determined by solving one-dimensional reaction/diffusion problems with finite volume method. The small-scale SMR conditions were considered, such as the reforming pressure of 1–3 bar, reforming temperature of 600–800 °C, and steam-to-carbon ratio of 2–4. The results showed the active thickness for the steam reforming and reverse methanation reactions hardly exceeded 0.15 mm for 600 °C, 0.07 mm for 700 °C, and 0.05 mm for 800 °C, at the reforming pressure of 1 bar. Besides, the effects of the volume-specific nickel surface area and diffusion properties were also investigated.

Electrochemical generation of hexacyanoferrate and hexacyanoruthanate electroactive films at nickel electrode surfaces: A promising synthetic approach for new electrode materials in metal ion batteries and supercapacitors

Prussian blue analogues (PBAs) have been recently investigated as promising electrode materials for battery and supercapacitor applications. While most explorations have focused on PBA nanoparticles, very little attention has been focused on PBA films deposited on a metallic support. In this work, we have examined electrogenerating hexacyanoferrate (HCF) and hexacyanoruthenate (HCR) films on nickel surfaces via cyclic voltammetry. We found that the total material deposited was influenced by the metal cation present in the electrolyte solution and that, on average, the rate of deposition of the surface adsorbed/immobilized species was dependent on the species in solution. In particular, films electrogenerated in the presence of Na+ and K+ had the highest deposition rates. The cyclic voltammetric profiles exhibited dramatic differences depending on the cation present in the electrolyte solution. In addition, we found that all films were electrochemically irreversible in the presence of Li+ and Mg2+ containing electrolyte solutions. Further, and as a proof of concept, we modified high surface area nickel electrodes with HCF in sodium-based electrolytes, finding that these electrodes could operate reversibly at equivalent C-rates as high as 1667C.

Upscaling high activity oxygen evolution catalysts based on CoFe2O4 nanoparticles supported on nickel foam for power-to-gas electrochemical conversion with energy efficiencies above 80%

We investigate cobalt ferrite nanoparticles (NPs) supported on large-scale electrodes as oxygen evolution reaction (OER) catalysts. Colloidal CoFe2O4 NPs were loaded on low-cost and high surface area nickel foam (NF) scaffolds. The coating process was optimized for large electrode areas, ensuring a proper distribution of the NPs on the NF that allowed overcoming the electrical conductivity limitations of oxide NPs. We were able to produce CoFe2O4-coated NFs having 10 cm2 geometric surface areas with overpotentials below 300 mV for the OER at a current density of 50 mA/cm2. Such impressively low overpotentials suggested using CoFe2O4 NP-based electrodes within a water electrolysis device. In this prototype device, stable operating currents up to 500 mA at remarkably low cell-voltages of 1.62 and 1.53 V, at ambient and 50 °C electrolyte temperatures, respectively, were reached during operation periods of up to 50 h. The high electrochemical energy efficiencies reached at 50 mA/cm2, 75% and 81% respectively, rendered these devices particularly appealing to be combined with low-cost photovoltaic systems for bias-free hydrogen production. Therefore, CoFe2O4 NP-based electrolysers were coupled to low-cost thin-film silicon solar cells with 13% efficiency to complete a system that afforded solar-to-fuel efficiencies above 10%.

Cyclic voltammetry measurements of electroactive surface area of porous nickel: Peak current and peak charge methods and diffusion layer effect

Surface area is a key parameter for porous metals for electrode applications. Here we measured the electroactive surface area of porous nickel samples using the cyclic voltammetry peak current and peak charge methods. The peak current method measures the contributions from primary pores, while the peak charge method measures the contributions from both primary and secondary pores. The electroactive surface area measured by both methods decreases with normalised diffusion layer thickness. It follows the semi-infinite model at low normalised diffusion layer thicknesses (<0.35) and the thin-layer model at high normalised diffusion layer thickness (>0.35). The correcting factors obtained from the semi-infinite model provide quantitative information on the pore surface roughness and the secondary porosity contribution. The surface roughness of the samples produced by Lost Carbonate Sintering is 2.15. The relative contribution of secondary porosity depends on the type of porous nickel and increases with scan rate, due to reduced diffusion layer thickness. It is in the range of 0.14–0.3 for the samples produced by Lost Carbonate Sintering and loose sintering, and 0.02–0.05 for the sample produced by electrodeposition, for scan rates in the range of 0.005–0.05 V/s.