How NiFoam-Supported NiMo Catalysts Are Changing the Game
In the quest for sustainable energy solutions, green hydrogen has emerged as a beacon of hope—a clean, energy-dense fuel that could potentially replace fossil fuels and help decarbonize our economy. Unlike conventional hydrogen production methods that rely on fossil fuels, green hydrogen is produced through electrochemical water splitting—using renewable electricity to split water molecules into hydrogen and oxygen without carbon emissions. However, this process requires highly efficient catalysts to make it economically viable. Enter Ni foam-supported NiMo catalysts: an innovative, cost-effective solution that is pushing the boundaries of what's possible in hydrogen production technology 3 .
Coupling water electrolysis with renewable energy sources such as wind and solar mitigates their intermittency, reduces carbon emissions, and enhances energy efficiency and sustainability 2 .
The hydrogen evolution reaction (HER) is the key half-reaction in water electrolysis that produces hydrogen gas. At its core, HER involves the reduction of protons or water molecules to form hydrogen gas, but this process faces significant kinetic barriers that slow down the reaction. Without catalysts, the reaction would require impractically high voltages to proceed at meaningful rates, making the process energetically and economically inefficient 2 .
In alkaline media, the HER mechanism proceeds through two primary steps:
The rate-determining step often involves the dissociation of water molecules, which is significantly slower in alkaline environments than the reduction of protons in acidic media 4 .
Slower reaction kinetics but less corrosive than acidic environments
Reduces energy barriers and increases reaction rates
When combined, nickel and molybdenum create a synergistic effect that surpasses the capabilities of either metal alone. The ranking of HER activity of Ni-based binary alloys places Ni–Mo at the top, followed by Ni–Zn > Ni–Co > Ni–W > Ni–Fe > Ni–Cr 6 . The Ni-Mo catalyst shows potent resistance to corrosion, superior electrical conductivity, and excellent catalytic activity 6 .
Ni-Mo > Ni-Zn > Ni-Co > Ni-W > Ni-Fe > Ni-Cr in HER activity of Ni-based binary alloys 6 .
Involves hydrothermal in situ growth of NiMoO₄ nanorod arrays on nickel foam followed by gas-phase reduction at high temperatures (typically 600°C) 2 .
Uses an electrochemical cell with nickel foam as the cathode immersed in a solution containing nickel and molybdenum salts 4 6 .
Constructs a self-supported electrocatalyst by anchoring a blade-shaped catalytic layer (Ni/MoO₂) onto a dense interlayer of MoO₂ nanoparticles 8 .
| Material/Reagent | Function in Catalyst Synthesis | Significance |
|---|---|---|
| Nickel Foam (NF) | 3D porous substrate for catalyst support | Provides high surface area, excellent conductivity, and mechanical stability |
| Nickel Salts (NiCl₂, NiSO₄) | Source of nickel ions for catalyst formation | Reduced to metallic Ni or alloyed with Mo in the final catalyst |
| Ammonium Molybdate | Source of molybdenum ions | Forms Mo-based compounds and alloys with nickel |
| Sodium Borohydride | Reducing agent | Reduces metal ions to their metallic form during synthesis |
| Ammonium Chloride (NH₄Cl) | Supporting electrolyte in electrodeposition | Critical for successful deposition in specific methods |
In a compelling 2025 study published in Molecules, researchers developed a sophisticated approach to creating highly efficient NiMo catalysts on nickel foam 2 . The process began with the hydrothermal in situ growth of NiMoO₄ nanorod arrays directly onto nickel foam substrates. This step was crucial for establishing a strong connection between the active material and the conductive support.
| Temperature (°C) | Overpotential @100 mA cm⁻² (mV) | Tafel Slope (mV dec⁻¹) |
|---|---|---|
| 400 | No complete reduction | - |
| 600 | 127 | 124 |
| 800 | 158 | 141 |
| 950 | 192 | 157 |
overpotential @100 mA cm⁻²
With exceptional stability over 45 hours of continuous operation
The 600°C-treated sample developed a unique "flower-spherical" morphology composed of interconnected nanosheets, providing increased specific surface area and more catalytically active sites 2 .
| Catalyst Type | Overpotential @10 mA cm⁻² (mV) | Overpotential @100 mA cm⁻² (mV) | Tafel Slope (mV dec⁻¹) | Stability Test Results |
|---|---|---|---|---|
| NiMo Nanoflower/NF 2 | 67 | 127 | 124 | 45 h with negligible degradation |
| Ni₄Mo-MoOₓ 4 | 32 | 190 (@1 A cm⁻²) | 65 | >100 h at high current densities |
| Int-Ni/MoO₂ 8 | 46 | 73 (@1000 mA cm⁻²) | 42 | 6000 h at -1000 mA cm⁻² |
| Pt/C (Benchmark) | 0-30 | ~150 | 30-40 | Gradual degradation over time |
The performance data reveals that advanced NiMo catalysts on nickel foam are becoming increasingly competitive with traditional platinum-based catalysts, especially in terms of stability at high current densities. The record-breaking stability of the Int-Ni/MoO₂ catalyst—demonstrating 6000 hours of continuous operation at -1000 mA cm⁻²—is particularly remarkable and represents a significant milestone toward industrial application 8 .
Combines benefits of both alkaline and proton exchange membrane electrolysis for cost-effective green hydrogen production 4 .
Ability to operate efficiently in simulated alkaline seawater conditions opens possibilities for direct seawater electrolysis 5 .
Exceptional stability at current densities exceeding 1000 mA cm⁻² makes them suitable for next-generation industrial electrolyzers 8 .
The integration of high-performance NiMo catalysts into AEMWE systems has demonstrated remarkable results, with some systems achieving stable operation at current densities as high as 3 A cm⁻² 4 .
Ni foam-supported NiMo catalysts represent more than just a scientific achievement—they embody the kind of innovation necessary to accelerate the transition to a sustainable energy future. By combining abundant elements in clever nanostructures supported on three-dimensional frameworks, researchers have created catalytic systems that rival precious metal performance at a fraction of the cost.
As research continues to refine these materials and scale up production methods, we move closer to the tipping point where green hydrogen becomes not just environmentally desirable but economically compelling. The development of these advanced catalysts brings us one step closer to a world where clean energy powers our industries, transportation, and homes—a truly transformative vision for our planetary future.