Earth-Abundant Chalcogenide Catalysts Could Unlock Cheaper Green Hydrogen at High Current Densities

Green hydrogen has long been billed as a cornerstone of the global energy transition, a fuel that could decarbonize sectors where electrification struggles, from heavy industry to long-haul transport. Yet the technology that produces it by splitting water remains stubbornly expensive and inefficient. A new peer-reviewed review published in Discover Sustainability examines one of the most promising routes out of that impasse: a family of earth-abundant materials known as transition metal chalcogenides, which may allow a single catalyst to drive both halves of the water-splitting reaction. The work, led by Michael Buenly B. Owogowog of De La Salle University with colleagues from the Philippine Department of Energy and Bicol University, consolidates recent advances and argues that these materials could underpin the next generation of high current density electrolyzers.

The core problem the review tackles lies in the chemistry of water electrolysis itself. Splitting water into hydrogen and oxygen involves two half-reactions: the hydrogen evolution reaction, which produces hydrogen gas at one electrode, and the oxygen evolution reaction, which releases oxygen at the other. Of the two, oxygen evolution is by far the more sluggish. Its kinetics are slow, demanding a large extra voltage, called an overpotential, beyond the thermodynamic minimum required to split water. That wasted energy translates directly into higher electricity bills and lower overall system efficiency, and it has been a persistent bottleneck for every electrolyzer design on the market.

Compounding the problem, the catalysts that currently tame the oxygen evolution reaction are precious. Conventional proton exchange membrane electrolyzers depend on noble metal catalysts, typically iridium and platinum group materials, which are scarce, expensive, and geographically concentrated. The review also points to a second vulnerability: these systems degrade under the intermittent, fluctuating power inputs that come hand in hand with wind and solar generation. An electrolyzer that only performs well when fed perfectly steady current is a poor match for a renewable grid, so cost and durability problems reinforce one another.

Transition metal chalcogenides offer a way around both constraints. These are compounds of transition metals, such as nickel, cobalt, iron, or molybdenum, combined with chalcogen elements like sulfur, selenium, or tellurium. Because their constituent elements are abundant in the Earth’s crust, they sidestep the supply chain risks and price volatility that plague noble metal catalysts. More importantly, their electronic structure gives them genuine catalytic talent. The review emphasizes that partially filled d-orbitals in these materials enable optimized adsorption of the reaction intermediates that form and vanish in the course of both the hydrogen and oxygen evolution reactions. Getting that adsorption energy right is the central art of electrocatalysis, because intermediates that bind too weakly never react, while those that bind too strongly poison the surface. Chalcogenides hit a favorable middle ground, lowering both the kinetic and thermodynamic barriers for the two half-reactions.

The most consequential property highlighted in the review is bifunctionality. Most electrolyzers to date have required different catalysts at the anode and the cathode, each optimized for its own half-reaction. A bifunctional transition metal chalcogenide can catalyze both the hydrogen evolution reaction and the oxygen evolution reaction within a single material system. That simplifies electrolyzer design considerably, reduces the number of distinct materials that must be synthesized, tested, and manufactured at scale, and opens the door to symmetric or reversible cell architectures in which the same electrode can switch roles. For a technology trying to drive down capital costs, collapsing two catalyst systems into one is a meaningful engineering advantage.

Conductivity is the third pillar of the case. Many abundant catalyst candidates fail not because they lack catalytic activity but because they are poor conductors, so electrons cannot reach the active sites efficiently. The review notes that transition metal chalcogenides possess metallic or semi-metallic conductivity, which improves charge transfer kinetics at the electrode surface. Faster charge transfer means less resistive loss inside the cell, which matters enormously when the goal is operation at high current density, the regime commercial electrolyzers must reach to produce hydrogen at scale. The materials also show enhanced resistance to corrosion, a critical trait in the harsh oxidative environment of the oxygen evolution electrode, where many otherwise promising compounds dissolve or crumble within hours.

Structurally, the review frames these advantages as arising from tunable electronic structures. Because the metal and chalcogen identities, stoichiometry, and crystal phase can all be varied, researchers have a broad design space in which to optimize adsorption energies and electronic properties. This tunability is what separates chalcogenides from a simple substitution story: rather than merely replacing iridium with something cheaper, designers can engineer the catalyst’s electronic landscape to suit specific operating conditions, electrolyzer configurations, and current density targets. The review consolidates synthesis strategies reported in recent literature and evaluates how the resulting catalysts perform across various electrolyzer configurations, providing a map of which approaches have delivered the strongest results so far.

The authors are candid that the field is not yet ready for prime time. Three challenges dominate their assessment: catalyst stability, scalability, and integration into commercial systems. Stability remains the hardest test, since laboratory measurements are often taken over hours while commercial electrolyzers must run for tens of thousands of hours under fluctuating load. Scalability raises the question of whether synthesis routes that work on milligram quantities in a beaker can be translated to the square meters of electrode area a commercial stack requires, without losing the nanostructured features that give the catalysts their activity. Integration, meanwhile, encompasses everything from electrode fabrication and membrane compatibility to how bifunctional catalysts behave in full devices rather than half-cell tests.

The significance of the review lies in its attempt to bridge these knowledge gaps and channel them into rational design principles. By systematically connecting synthesis strategies, electronic structure, and measured performance, it aims to give researchers a framework for designing cost-effective, high-performance bifunctional electrocatalysts rather than discovering them by trial and error. The timing is pointed. As nations commit to net-zero emission targets, demand for low-carbon hydrogen is projected to grow sharply, and the economics of production will determine whether that demand is met with genuinely green hydrogen or with fossil-derived alternatives. Catalyst cost is one of the levers that most directly shapes those economics.

The work also carries a regional dimension. The research team, based at De La Salle University in Manila and supported by a grant from the Philippine Department of Science and Technology through its Council for Industry, Energy, and Emerging Technology Research and Development, reflects growing scientific engagement with the hydrogen economy in Southeast Asia, a region whose island geography and renewable potential make energy storage and clean fuels particularly salient. If bifunctional transition metal chalcogenides can clear the stability and scalability hurdles the review identifies, the payoff would be electrolyzers that run at high current density, tolerate the stop-and-go rhythm of renewable power, and cost a fraction of today’s noble metal systems. That combination, the authors argue, is what it will take to move green hydrogen from a promising cornerstone to a load-bearing one.

Subject of Research: Bifunctional transition metal chalcogenide electrocatalysts for high current density water electrolysis and green hydrogen production

Article Title: Harnessing bifunctional transition metal chalcogenides for high current density sustainable electrolyzer technologies

Article References: Owogowog, M. B. B., Flaviano, A. L., Morente, P. R. O., & Ortenero, J. R. (2026). Harnessing bifunctional transition metal chalcogenides for high current density sustainable electrolyzer technologies. Discover Sustainability. https://doi.org/10.1007/s43621-026-04758-6

Image Credits: AI Generated

DOI: 10.1007/s43621-026-04758-6

Keywords: green hydrogen, water electrolysis, electrocatalysis, transition metal chalcogenides, oxygen evolution reaction, hydrogen evolution reaction, bifunctional catalysts, proton exchange membrane, overpotential, catalyst stability, renewable energy, electrolyzer technology