About

Héctor D. Abruña is the Emile M. Chamot Professor at Cornell University, with a research focus on the development and characterization of new materials for fuel cells, batteries, and molecular electronics. His work employs an interdisciplinary approach, utilizing electrochemical techniques as probes of various chemical systems, complemented by x-ray based methods, differential electrochemical mass spectrometry, in-situ FT-IR, scanned probe microscopies, scanning electrochemical microscopy, and low temperature conductance and spectroscopic techniques. His current research areas include the use of ordered intermetallics such as BiPt for electrocatalytic oxidation in fuel cells, mechanistic studies using DEMS and in-situ FT-IR, development of in-situ TEM techniques for fuel cell and battery materials, as well as the synthesis and testing of organic molecules for electrical energy storage devices like batteries and supercapacitors. Additionally, he investigates molecular electronics through the synthesis of nanometric building blocks, transport measurements, and the study of graphene as an electrochemical platform. His contributions have significantly advanced understanding in electrochemical phenomena and materials for energy applications.

Research topics

• Chemistry
• Organic chemistry
• Chemical engineering
• Materials science
• Nanotechnology
• Physical chemistry
• Inorganic chemistry

Selected publications

• Rational design of high-performance low-loading oxygen reduction catalysts for alkaline fuel cells

  Nature Materials · 2026-01-02 · 5 citations

  articleSenior author
  PublisherDOI

• Unveiling the sensitivity and significance of the Ni oxidation state for alkaline hydrogen oxidation electrocatalysis

  Proceedings of the National Academy of Sciences · 2026-03-18

  articleOpen accessSenior authorCorresponding

  The development of nonprecious-metal-based hydrogen oxidation reaction (HOR) electrocatalysts remains as the bottleneck for achieving high-performance, platinum group metal-free (PGM-free) alkaline/anion exchange membrane fuel cells. Numerous efforts have been dedicated toward enhancing the HOR activity of Ni catalysts due to the lack of alternative choices. However, mechanistic insights relating to electrocatalytic activity and degradation remain a matter of debate, and proposed models tend to lack conclusive experimental evidence. Here, we studied the state of Ni catalysts using scanning transmission electron microscopy and electron energy loss spectroscopy, together with in situ high energy resolution fluorescence detected X-ray absorption spectroscopy. The results revealed that a metallic Ni surface is crucial for effectively catalyzing the HOR, and that the formation of α-Ni(OH) 2 at potentials positive of +0.3 V vs. RHE leads to deactivation of the catalyst. Further analysis with theoretical calculations revealed a strong interaction between the Ni surface and graphene, resulting in a tightly sealed carbon shell that protects the Ni surface. The analysis further indicates that HOR occurs on graphene-protected Ni@C catalysts through the transport of hydrogen and protons across the carbon shell, particularly at self-healing larger holes. Using the Ni@C catalyst, together with evidence-informed experimental protocols to avoid oxidation before, during, and after membrane electrode assembly fabrication and testing, we achieved a milestone PGM-free AEMFC peak power density performance of 1.0 W/cm 2 . This is a demonstration of a Watt-scale performance for a PGM-free AEMFC.

  PublisherDOI

• A seven-facet polyhedron captures the composition-only formation-energy landscape of inorganic solids

  ArXiv.org · 2026-01-30

  articleOpen access

  This work demonstrates that the convex hull of formation energies for solid compounds involving elements from hydrogen to uranium admits a remarkably simple description over the 92-dimensional space of chemical compositions, despite the enormous combinatorial complexity of possible atomic structures. By training an interpretable max-affine model directly on near-hull formation energies from the Materials Project density-functional theory (DFT) database, we find that the hull can be reconstructed to DFT accuracy using a polyhedron with only seven facets. These facets define seven chemically coherent materials classes, with just seven coefficients per element sufficing to capture the dominant energetic trends across composition space. Remarkably, this compact, composition-only representation generalizes far beyond bulk formation energies. Without retraining or structural input, the same model reproduces trends in DFT-calculated defect formation energies, captures experimentally observed elemental mixing correlations in high-entropy materials, and enables the construction and optimization of Pourbaix diagrams for electrochemical stability. Together, these results show that many materials properties governed by energy differences can be expressed as simple linear combinations of a small set of interpretable, element-specific parameters. The result is a bonding-geometry-free thermodynamic framework that unifies stability, defects, mixing, and electrochemistry, and enables rapid, interpretable screening across vast chemical spaces.

  PublisherOA PDF

• Catalyst-, Potential-, and pH-Dependent Product Selectivity of NO Electroreduction on Transition Metals Studied by Coupled Differential Electrochemical Mass Spectrometry and Surface-Enhanced Infrared Absorption Spectroscopy

  Journal of the American Chemical Society · 2026-05-08

  articleSenior authorCorresponding

  The electrochemical NO reduction reaction (NORR) has been exploited as an alternative method to scrub NO from industrial and residential effluents as well as a route for ammonia synthesis. However, the product selectivity and electroactivity are strongly affected by numerous factors, and the detailed mechanism remains elusive. In this work, the NORR on Pd, Ru, Ir, Au, Ag, and Cu in both alkaline and acidic media was studied with coupled differential electrochemical mass spectrometry and attenuated total reflection–surface-enhanced infrared absorption spectroscopy. The potential-dependent product formation in both alkaline and acidic media and surface-adsorbed species could be simultaneously monitored, enabling us to correlate the product selectivity with adsorbed species and to elucidate the NORR mechanism. At potentials >0.4 V, N2O was the dominant product on all studied metals, and the kinetics for N2O formation were enhanced in alkaline media when compared to acidic media. Cu was the most selective and effective catalyst for the NORR to NH3/NH2OH. NH3/NH2OH were also the predominant products on Pt, Ru, and Ir in both alkaline and acidic media and on Ag and Au in alkaline media at potentials of hydrogen evolution/adsorption. The NORR on Pd selectively generated N2 at 0.175 V in alkaline media but not in acidic media. These in situ experimental data provide new mechanistic insights into the NORR selectivity that could inform/guide the design of more effective and selective NORR catalysts and establish optimal operation conditions for the electrochemical synthesis of selected products.

  PublisherDOI

• Modular multi-interface nanocrystals for enhanced ethanol oxidation electrocatalysis

  Matter · 2026-02-20 · 2 citations

  article
  PublisherDOI

• A seven-facet polyhedron captures the composition-only formation-energy landscape of inorganic solids

  Open MIND · 2026-01-30

  preprint

  This work demonstrates that the convex hull of formation energies for solid compounds involving elements from hydrogen to uranium admits a remarkably simple description over the 92-dimensional space of chemical compositions, despite the enormous combinatorial complexity of possible atomic structures. By training an interpretable max-affine model directly on near-hull formation energies from the Materials Project density-functional theory (DFT) database, we find that the hull can be reconstructed to DFT accuracy using a polyhedron with only seven facets. These facets define seven chemically coherent materials classes, with just seven coefficients per element sufficing to capture the dominant energetic trends across composition space. Remarkably, this compact, composition-only representation generalizes far beyond bulk formation energies. Without retraining or structural input, the same model reproduces trends in DFT-calculated defect formation energies, captures experimentally observed elemental mixing correlations in high-entropy materials, and enables the construction and optimization of Pourbaix diagrams for electrochemical stability. Together, these results show that many materials properties governed by energy differences can be expressed as simple linear combinations of a small set of interpretable, element-specific parameters. The result is a bonding-geometry-free thermodynamic framework that unifies stability, defects, mixing, and electrochemistry, and enables rapid, interpretable screening across vast chemical spaces.

  DOI

• Cations Affect Water Activation on Pt(111) in Alkaline Media

  Journal of The Electrochemical Society · 2025-01-01 · 7 citations

  articleOpen access

  Water activation, oxidatively to produce surface-bound hydroxide (OH*) or reductively to form surface-bound hydrogen (H*) atoms, is ubiquitous in electrocatalysis. We report the impact of cations on the kinetics of the OH* and H* formation from water on single-crystal Pt(111) in alkaline using fast-scan-rate cyclic voltammetry. Isolating the dependence of the electro-adsorption kinetics on pH and ionic strength led to the observation that ion concentrations affected the OH* formation kinetics more strongly than pH. The H* formation exhibited similar behavior, even though the OH* formation rate was observed to be faster by >10x. We attributed the observed ion concentration effect to cations, given that switching cations (from Na + to Li + ) had a bigger impact on the H* and OH* formation rates than switching pH (effectively changing OH – to F – ). We hypothesize the cations softened and allowed the interfacial water layer to more easily reorganize. This result suggests that interfacial water disruption should benefit both H* and OH* electro-adsorption kinetics in alkaline electrolytes.

  PublisherDOI

• Effective Atom Theory: Gradient-Driven ab initio Materials Design

  ArXiv.org · 2025-09-08

  preprintOpen access

  We introduce Effective Atom Theory (EAT), a framework that transforms combinatorial materials design into a smooth, gradient-driven optimization within density functional theory (DFT). Atoms are represented as probabilistic mixtures of elements, enabling gradient-based optimizers to converge to a physically realizable material in about 50 energy evaluations -- far fewer than combinatorial optimization methods. Applied to Co-Cr-Ni-V oxides for the alkaline oxygen evolution reaction (OER), EAT leads to a final recommended composition of Co0.19Cr0.06V0.31Ni0.44O.

  PublisherOA PDFDOI

• Nitrogen Coordinated Iron on Porous Carbon–Titanium Nitride Hybrid: A Non-precious Metal Catalyst for the 4e^– ORR Pathway

  ACS Catalysis · 2025-08-02 · 9 citations

  article

  A nitrogen coordinated iron (Fe–N) on porous carbon/carbon nitride support decorated with titanium nitride nanoparticles, Fe–N–C/TiN, was prepared by a simple and scalable method and evaluated as a non-precious metal group oxygen reduction reaction (ORR) electrocatalyst for anion-exchange membrane fuel cells. The samples synthesized by a one-pot reaction followed annealing at 750 °C contain Fe–N–C sites on porous carbon/carbon nitride decorated with TiN nanoparticles and exhibit a high surface area of 620 m2 g–1. 57Fe Mössbauer spectroscopy reveals the presence of FeN4 active centers, whose formation is facilitated only by the presence of TiN nanoparticles. ORR testing shows a half-wave potential of 0.89 V with a limiting current of 5.5 mA cm–2 following the 4-electron pathway to water with only 5% HO2– formation during ORR in alkaline media, outperforming the PtC benchmark catalyst. The efficient ORR performance is attributed to the presence of FeN4 active sites and the high specific surface area of the support. Moreover, the material exhibited stable electrochemical performance during 10,000 ORR cycles. This straightforward and scalable approach offers a pathway to synthesize next-generation, high performance non-precious metal-based electrocatalysts with accessible Fe–N4 active sites for fuel cell and electrolyzer applications.

  PublisherDOI

• Regulated Li₂S Deposition through Evolution of Silver Chloride for Li–S Batteries

  ACS Nano · 2025-05-14 · 9 citations

  articleSenior authorCorresponding

  Lithium–sulfur (Li–S) batteries hold great promise as a next-generation energy storage system due to their high theoretical energy density (2600 W h kg–1), surpassing conventional lithium-ion batteries. However, their performance is often limited by the intrinsic transformation of soluble lithium polysulfides (LiPSs) into short-chain insoluble sulfur species (Li2S2/Li2S), which induces significant cell polarization, particularly under lean-electrolyte conditions. Through a galvanic replacement reaction (GRR), enabling precise tailoring of interfacial properties, AgCl-PVP nanocubes (NCs) were synthesized and utilized as sulfur host materials. These materials demonstrated effective entrapment of LiPSs, as confirmed by in situ electrochemical visualization. Furthermore, the AgCl-PVP NCs significantly reduced whole-cell polarization, particularly during the Li2S nucleation step, as validated by galvanostatic intermittent titration technique across the depth of discharge. Under lean-electrolyte conditions (5.6 μL mg–1), the AgCl-PVP NCs cathode exhibited high specific capacity (563.62 mA h g–1 at 0.2 C) with a low-capacity decay rate (1.81% per cycle). These results demonstrate the potential of GRR-engineered nanostructures as sulfur host material for enhancing the electrochemical performance and practical applicability of lean-electrolyte Li–S batteries.

  PublisherDOI

Frequent coauthors

• Francis J. DiSalvo

  Cornell University

  114 shared

• Yao Yang

  Chongqing University

  78 shared

• David A. Muller

  Cornell University

  78 shared

• F. Pariente

  Biosensores (Spain)

  67 shared

• Encarnación Lorenzo

  Universidad Autónoma de Madrid

  58 shared

• Hongsen Wang

  Cornell University

  49 shared

• Seung‐Ho Yu

  Korea University

  49 shared

• Yasuyuki Kiya

  Subaru (Japan)

  47 shared

Awards & honors

• 2025 Dreyfus Prize in the Chemical Sciences
• Enrico Fermi Award
• Global Energy Prize