The synthesis involved pyrolyzing graphitic carbon nitride, glucose and metal precursors to generate nitrogen-doped carbon supports containing dispersed metal oxide species. This route yielded three single-metal materials—Fe/NC, Ni/NC and Mn/NC—and two bimetal materials, NiFe/NC and MnFe/NC. Material characterization showed that the metal oxide species were dispersed within the nitrogen-doped carbon matrix. The results therefore support the method as a facile route to a family of supported catalysts with different metal combinations.

Catalyst activity varied across the series. Fe/NC and MnFe/NC shared the highest reported onset potential, 0.900 V versus the reversible hydrogen electrode. The remaining onset potentials were 0.873 V for Mn/NC, 0.842 V for NiFe/NC and 0.800 V for Ni/NC. These values describe the potentials at which oxygen-reduction activity was detected in the reported electrochemical evaluation. They place the two leading materials near the study’s Pt/C benchmark, while the full comparison also shows that catalyst composition was associated with substantial differences in measured performance.

All five synthesized catalysts followed what the investigators described as a favorable quasi-four-electron transfer pathway during oxygen reduction. The supplied findings do not specify the detailed reaction intermediates, selectivity measurements or kinetic parameters underlying that assignment, so the result should be understood as a reported characteristic of the catalyst series rather than as a complete mechanistic description. The study also found that the bimetal catalysts exhibited excellent reported ORR durability, with minimal current degradation and stable chronoamperometry profiles that were better than those of the single-metal catalysts.

Overall, the research identifies two complementary outcomes from the tested catalyst series: Fe/NC and MnFe/NC delivered the highest onset potentials, while NiFe/NC and MnFe/NC showed the strongest reported durability among the materials examined. The evidence comes from laboratory synthesis, material characterization and electrochemical testing, and the supplied findings do not establish performance in a complete fuel cell or metal–air battery. Nevertheless, the results show that a straightforward pyrolysis route can produce both single-metal and bimetal catalysts supported on nitrogen-doped carbon with promising ORR activity and stability under the conditions assessed.

Subject of Research: Laboratory synthesis and electrochemical evaluation of single- and bimetallic nitrogen-doped carbon catalysts for the oxygen reduction reaction

Article Title: Facile synthesis of single- and bimetal catalysts supported on nitrogen-doped carbon for the oxygen reduction reaction

Article References: Kesuma, A. R. D., Saraswati, T. E., Napporn, T. W., Santria, A., & Wibowo, A. H. (2026). Facile synthesis of single- and bimetal catalysts supported on nitrogen-doped carbon for the oxygen reduction reaction. Journal of Materials Science, 61(40), 30598-30612. https://doi.org/10.1007/s10853-026-13493-2

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13493-2

Keywords: oxygen reduction reaction, nitrogen-doped carbon, iron catalyst, manganese catalyst, nickel catalyst, bimetallic catalysts, electrocatalysis, pyrolysis, chronoamperometry, fuel-cell materials, Facile, synthesis

The experimental work, reported in Catalysis Letters, focused on optimizing the bimetallic composition of NiCo LDH/TiO2 electrocatalysts. The catalysts were constructed on nickel foam through a hydrothermal method, after which the nickel-to-cobalt ratio was systematically varied. Layered double hydroxides were described as offering tunable structures and abundant active sites, but also as suffering from poor conductivity. The investigators therefore examined how the composition affected the composite catalyst’s structure, electrochemical behavior and hydrogen-evolution performance.

Structural characterization confirmed the presence of TiO2 and the characteristic chemical states of NiCo LDH in the composites. At the selected 2:1 Ni/Co ratio, the material formed nanosheets that were distributed uniformly and had an open porous architecture. The nanosheets also made close contact with the TiO2 component. These observations identify the morphology and interfacial structure associated with the best-performing composition, rather than establishing a separate causal mechanism for its measured electrochemical performance.

Electrochemical measurements showed that the optimized catalyst had the lowest charge-transfer resistance and the highest double-layer capacitance of the samples examined. Its double-layer capacitance reached 3.87 mF·cm−2. The researchers interpreted these findings as consistent with facilitated charge transfer and increased exposure of active sites. At a current density of 10 mA·cm−2 in 1 M KOH, the 2:1 Ni/Co catalyst required an overpotential of 86.8 mV, while its Tafel slope was 61 mV·dec−1. These values were reported for the optimized composite; the supplied evidence does not provide the complete numerical results for every comparison formulation.

The researchers also assessed operational stability through chronoamperometry at a constant potential for 10 hours. The available study abstract reports the duration and method of this stability assessment but does not state a separate numerical current-retention value. Taken together, the results connect systematic Ni/Co composition optimization with the observed nanosheet morphology, lower charge-transfer resistance, higher double-layer capacitance and enhanced hydrogen-evolution activity in alkaline electrolyte. The work provides a compositional design basis for layered-double-hydroxide composite catalysts, although the reported evidence is limited to laboratory electrochemical testing rather than operation at an industrial scale.

Subject of Research: Experimental optimization of NiCo LDH/TiO2 electrocatalysts for alkaline hydrogen evolution

Article Title: Composition Optimization of NiCo LDH/TiO2 for Boosted Electrocatalytic Hydrogen Evolution

Article References: Qiao, F., Ren, Z., & Liu, J. (2026). Composition Optimization of NiCo LDH/TiO2 for Boosted Electrocatalytic Hydrogen Evolution. Catalysis Letters, 156(11), Article 308. https://doi.org/10.1007/s10562-026-05552-9

Image Credits: AI Generated

DOI: 10.1007/s10562-026-05552-9

Keywords: hydrogen evolution, electrocatalysis, NiCo LDH, titanium dioxide, alkaline electrolyte, layered double hydroxides, nanosheets, chronoamperometry, charge-transfer resistance, potassium hydroxide, Composition, Optimization

The research team, led by Dipali Potdar of Jaysingpur College and Shivaji University together with colleagues including corresponding authors Shivaji Sadale and Prashant Chikode, electrodeposited nickel thin films onto 304-grade stainless steel substrates from simple sulfate baths. They systematically varied three parameters that any plating shop can control: the applied deposition potential, the pH of the electrolyte, and the concentration of nickel ions in solution. By sweeping nickel sulfate concentrations from 25 to 50 millimolar and adjusting pH from 4 to 8 with ammonium hydroxide, they created a matrix of deposition conditions whose effects could be traced all the way from current signatures to crystal structure.

The central analytical tool was the Scharifker-Hills model, a theoretical framework developed in 1983 that remains the workhorse for interpreting nucleation during electrodeposition. The model distinguishes between two limiting behaviors. In instantaneous nucleation, all active sites on the electrode surface are occupied essentially at once, so the number of nuclei is fixed from the start and each nucleus simply grows. In progressive nucleation, new sites continue to activate throughout the deposition, so the population of nuclei keeps increasing. The shape of the current-time transient, recorded when a fixed potential is applied, carries the fingerprint of whichever mechanism dominates, and comparing normalized experimental curves against the model’s dimensionless predictions reveals the mechanism at work.

Before diving into transients, the team used cyclic voltammetry to establish the electrochemical landscape of their bath. Sweeping the potential from 0.7 volts down to minus 1 volt against a silver-silver chloride reference electrode, they observed a stable current until an onset potential near minus 0.7 volts, followed by a rapid rise and a cathodic peak at minus 0.88 volts, which they attribute to the reduction of nickel ions on the stainless steel surface. A further surge at more negative potentials signaled the onset of the hydrogen evolution reaction, the parasitic process that plagues nickel plating by generating gas bubbles at the electrode. Two crossover points on the reverse scan, at minus 0.78 and minus 0.43 volts, marked the initiation of nucleation and the adsorption of nickel ions on the surface, while an anodic peak at minus 0.2 volts reflected nickel oxidation.

The voltammetry also revealed that the deposition reaction is diffusion-controlled. Recording curves at scan rates of 10, 20, and 30 millivolts per second, the researchers found that the anodic peak current density scaled linearly with the square root of the scan rate, exactly the relationship predicted by the Randles-Sevcik equation for a process limited by how fast nickel ions can travel to the electrode. This diffusion control proved crucial for interpreting everything that followed, because when ions arrive at the surface faster than they can be replenished from the bulk solution, the geometry of the depletion zones around growing nuclei shapes both the current response and the final film morphology.

Chronoamperometry, the recording of current as a function of time at a fixed applied potential, then exposed the three-act drama of nickel electrocrystallization. In the first fraction of a millisecond, a sharp spike and decay of current reflects double-layer charging and ion adsorption. A rapid rise follows as new nuclei form and each one draws a hemispherical diffusion zone around itself, pushing the current to a maximum. Beyond that peak, the current decays in a manner governed by the Cottrell equation, the classic signature of diffusion-limited mass transfer, before settling into a plateau where the supply of nickel ions from the bulk solution constrains everything. This characteristic profile confirmed that nickel deposition on stainless steel follows a three-dimensional nucleation process, with hemispherical clusters growing and eventually coalescing into a continuous film.

The comparison with the Scharifker-Hills model produced the study’s most striking finding: the nucleation mechanism is not fixed but shifts with deposition conditions. At underpotentials, where the driving force is modest, the transients tracked the progressive nucleation curve, because the nucleation rate lagged behind the growth rate and new sites kept activating. At overpotentials, the curves aligned closely with instantaneous nucleation, since the nucleation barrier is overcome quickly and a large population of nuclei forms simultaneously. At the reduction potential itself, a mixed mechanism appeared. Raising the bath pH from 4 to 8 pushed the system toward progressive nucleation, which the authors attribute to pH-dependent changes in hydroxide species and surface energetics that favor the continuous creation of new nucleation sites over time.

Concentration played an equally decisive role. Films grown from the most dilute 25 millimolar bath followed the instantaneous nucleation curve, while the 37 and 50 millimolar baths produced mixed instantaneous and progressive behavior, echoing earlier observations of silver deposition on glassy carbon. The team notes that experimental curves deviated from ideal theory in places, with a slower current decay than predicted, which they attribute to side processes such as hydrogen evolution, adsorption, and charge-transfer resistance. These deviations are a reminder that real plating baths are chemically messy systems, and that the clean limiting cases of nucleation theory blend into one another under practical conditions.

What makes the study compelling is that the electrochemical fingerprints translated directly into physical film quality. X-ray diffraction confirmed the cubic crystal structure of nickel in every film, with a prominent reflection from the (111) planes at 44.5 degrees, and the Williamson-Hall analysis of peak broadening revealed compressive microstrain induced by the stainless steel substrate. Notably, crystallite size, lattice constant, and texture coefficient barely changed across the parameter range, but strain and dislocation density dropped to negligible levels at the highest pH and concentration. Meanwhile, field-emission scanning electron microscopy showed a dramatic morphological transition: films from acidic, dilute baths were rough and cracked, riddled with grain boundaries, while films from alkaline, concentrated baths were smooth, uniform, and compact. The culprit behind the cracking is the hydrogen evolution reaction, whose disruptive bubbles and induced internal stress scar the growing film at low pH but are largely suppressed in alkaline conditions.

The practical implications ripple outward from the plating bath. The authors point out that cracked, fine-grained films with abundant grain boundaries resist dislocation movement and are therefore harder, but the same boundaries promote corrosion, whereas the coarser, compact films grown at higher pH and concentration conduct electricity better and resist corrosion. Because nickel coatings serve industries ranging from metal decoration and electronic components to catalysis and energy storage, the ability to dial in a specific nucleation mechanism and morphology through nothing more exotic than pH, concentration, and potential offers a low-cost route to tailored coatings. The researchers acknowledge support from the Mahatma Jyotiba Phule Research and Training Institute, and their work stands as a reminder that some of the most consequential physics in manufacturing happens in the first milliseconds, when a handful of atoms decides what kind of surface the world will see.

Subject of Research: Nucleation and growth kinetics during the electrodeposition of nickel thin films on stainless steel

Article Title: Studies on nucleation and growth kinetics during electrodeposition of nickel thin films

Article References: Potdar, D., Patil, S., Kulkarni, Y., Pawar, N., Banne, S., Sadale, S., & Chikode, P. (2026). Studies on nucleation and growth kinetics during electrodeposition of nickel thin films. Discover Electrochemistry, 3(1), Article 29. https://doi.org/10.1007/s44373-026-00115-4

Image Credits: AI Generated

DOI: 10.1007/s44373-026-00115-4

Keywords: electrodeposition, nickel thin films, nucleation kinetics, Scharifker-Hills model, chronoamperometry, cyclic voltammetry, stainless steel substrate, hydrogen evolution reaction, X-ray diffraction, FESEM, bath pH, crystal growth