Climbing and Moving the Volcano: An Active-Site-Centric Framework for Mastering Electrocatalytic Scaling Relations

ConspectusA sustainable hydrogen economy relies on efficient electrochemical reactions including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and nucleophilic oxidation reactions (NORs). The performance of electrocatalysts, however, is fundamentally constrained by ubiquitous scaling relations between the adsorption energies of key reaction intermediates. These relations are embodied in the classic volcano curve, whose apex marks both the optimal achievable catalytic activity and an inherent theoretical ceiling for performance. Advancing the field therefore relies on two conceptually distinct strategies, the first focused on climbing the volcano through rational catalyst design to systematically approach its apex, and the second centered on shifting the volcano via multiple sites engineering that breaks the underlying scaling relations to transcend this intrinsic limit. In this Account, we summarize our group's systematic efforts in the rational design of electrocatalysts through an active-site-centric framework that enables both of these strategies. We consolidate our work into four targeted approaches for engineering active sites, each directly addressing the volcano curve's constraints. First, the most foundational approach centers on climbing the volcano via fine-tuning single metal active sites, targeting systematic ascent toward the volcano's apex. We demonstrate that precise modulation of single metal centers' local geometric and electronic structures, via support regulation or defect introduction, finely tunes intermediate adsorption energies toward the theoretical optimum. Next, our strategy shifts the volcano via dual metal synergy. To break linear scaling relations (LSRs) defining the volcano's boundaries, we engineer dual metal sites, where a second distinct metal enables adjacent atomic sites to preferentially bind different intermediates and decouple their correlated adsorption energies. Beyond the dual metal site design, an equally powerful volcano-shifting approach uses active sites that operate via metal-ligand pathways, where ligands such as O, S and oxyanions directly participate in catalysis to open nontraditional pathways. Finally, our framework's most promising strategy shifts the volcano via ligand-ligand coupling, engineering local ligand-ligand configurations to trigger direct O-O bond formation, completely bypassing the traditional adsorbate evolution mechanism (AEM). In summary, our active-site-centric framework establishes a powerful and generalizable roadmap for electrocatalyst design. By anchoring design principles to the fundamental pillars of heterogeneous catalysis, namely active site tuning, reaction pathway steering, and scaling relation manipulation, this framework enables rational and predictable catalyst engineering, allowing us to either climb the existing volcano curve for targeted optimization or shift the volcano landscape to break intrinsic performance ceilings. Importantly, this design paradigm is not restricted to water splitting electrocatalysis, and delivers universal guiding value across the full scope of the energy catalysis field.