Facet Modulation of Interfacial Water Structure Tunes Electrocatalytic Hydrogen Reaction Kinetics
Year: 2026
Type: article
Abstract: Interfacial water structure is theoretically envisioned as the master regulator of electrocatalytic reaction kinetics, but the direct experimental validation of this role has remained a formidable challenge. Probing kinetic isotope effects (KIEs) is paramount to deciphering the elusive proton-coupled electron transfer (PCET) mechanisms in alkaline media, a long-standing enigma in electrocatalysis. Such precision, however, demands the uncompromising rigor of atomic-level-precise single-crystal electrodes and ultrapure D2O to ensure definitive results. Here, we uncover a hydrogen evolution reaction KIE that varies sharply with the surface structure: ∼6 for Pt(100), ∼1 for Pt(111), and intermediate values for Pt(110). Through a combination of nuclear-electronic orbital density functional theory (NEO-DFT) and in situ laser-induced temperature-jump (LITJ) experiments, we propose that this disparity originates from the difference between a rigid, hexagonal H-bonded network on Pt(111) and a more disordered, flexible interfacial layer on Pt(100) that would be more sensitive to isotopic substitution, as well as from differences in H/D adsorption sites, which would influence the effective proton transfer distances. Furthermore, measurements with stepped surfaces show that step density acts as a critical dial to tune these water environments. Finally, to bridge the knowledge gap between bulk single-crystals and practical nanoparticles, {100}-oriented Pt nanocubes and {111}-oriented Pt nanotetrahedrons reveal a facet-dependent KIE trend comparable to their single-crystal counterparts. These insights provide a transformative framework for the rational design of high-performance interfaces for green hydrogen production.
DOI: 10.1021/jacs.6c11313
Institutions: Cornell University, Princeton University, University of Alicante
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Funders: National Science Foundation, Ministerio de Ciencia, Innovación y Universidades, Generalitat Valenciana, Cornell Atkinson Center for Sustainability, Cornell University, Kavli Institute at Cornell, Cornell University, Energy Frontier Research Centers, National Science Foundation Graduate Research Fellowship Program
Awards: Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, CAREER: Dynamic Catalyst Evolution from Atoms to Active Nanostructures Probed by Operando Methods, G221072225, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), Cornell Center for Materials Research - MRSEC, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), G4866112958, Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), Mid-scale: Operations of the Center for High Energy X-ray Science (CHEXS), G6538397829, G7553145550, G8128299503, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI
OpenAlex ID: W7207763239